This study was funded by the Zhejiang Provincial Natural Science Foundation of China (Grant No: LY17H270016), the National Natural Science Foundation of China (Grant No: 81774331, 81873049, and 81673997), and the Zhejiang Provincial Science and Technology Project of Traditional Chinese Medicine of China (Grant No: 2013ZQ007 and 2016ZZ011).

Procedures involving animal subjects have been approved by the Medical Norms and Ethics Committee of Zhejiang Chinese Medical University and are in accordance with the China legislation on the use and care of laboratory animals.
1. Intra-articular injection of mono-iodoacetate in the knee
<ol>
	<li>After one-week of acclimation, randomly and equally divide 40 male Sprague-Dawley rats weighing 180&#8722;200 g (4&#8722;5 weeks old) into four groups (n = 10 rats/group). 
	NOTE: Rats in the control group will be intra-articularly injected with 50 &#181;L of saline, while rats in the experimental groups will be treated with 0.5, 1.5 or 3 mg of MIA dissolved in 50 &#181;L of saline, respectively.</li>
	<li>On the day of injection, freshly prepare the solution of MIA in sterile saline (0.9% NaCl) at 15, 30 and 60 mg/mL concentration and 10% pentobarbital solution in sterile saline (0.9% NaCl). 
	CAUTION: MIA has an extremely destructive effect on the mucous membrane, the upper respiratory tract, the eye and the skin and other tissue. Therefore, mask and gloves are recommended when preparing a solution.</li>
	<li>Anesthetize rats by intraperitoneal injection of ketamine at 60 mg/kg and xylazine at 5 mg/kg (both prepared in&#160;saline). Gently clamp the toes of the rat with a tweezer to confirm anesthesia.</li>
	<li>Place the rat with its back facing down. Shave the knee and wipe the area surrounding the knee joint with alcohol.</li>
	<li>Keep the knee at a 90&#176; angle and reveal the white patellar tendon below the patella. Press the patellar tendon with the fingertip to find the gap beneath the patella.</li>
	<li>Choose the junction of the gap and the lateral patellar tendon as the injection site. Then, insert the 26 G needle vertically into the site about 5 mm. No resistance should be felt when the needle is in the articular space. 
	NOTE: It is important to keep the needle perpendicular to the injection site.</li>
	<li>Inject 50 &#181;L of saline or MIA solution into the joint cavity. Slowly pull out the needle and wrap a piece of gauze around the injection site to minimize reflux and leakage.&#160;After anesthesia recovery, remove the gauze.</li>
	<li>Test pain-related behavior at 1, 7, 14, 21, 28 and 35 days after injections as described in section 2.</li>
</ol>
2. Behavioral assessments
<ol>
	<li>Mechanical withdrawal threshold (MWT) 
	NOTE: The MWT was measured by the von Frey test13 and the observer was blinded to the injections that the animals had received.
	<ol>
		<li>Place a rat in an elevated plastic cage (17 cm x 11 cm x 13 cm) with a wire mesh base suspended 50 cm above a table. Ensure the testing environment is quiet and give the rat 30 min to adapt to the environment.</li>
		<li>Press the von Frey needle perpendicularly on the plantar surface of each rat&#8217;s hind paw. Increase the pressure gradually (approximately 20 g/s) and linearly until paw lifting or paw licking occurs.</li>
		<li>Use a force lower than the previous threshold to ensure that the threshold is the minimum withdrawal force. Test each rat more than three times, at least 3&#8722;5 min apart.</li>
		<li>Record the minimal force eliciting a paw withdrawal reflex. Average the data as the MWT of rats.</li>
	</ol>
	</li>
	<li>Thermal withdrawal latency (TWL) 
	NOTE: The TWL was measured using the plantar test apparatus (Table of Materials) and the observer was blinded to the injections that the animals had received.
	<ol>
		<li>Place a plexiglass box (60 cm x 20 cm x 14 cm, divided into 6 compartments) on a 3 mm thick glass plate, and put rats into the box (one in each compartment). Ensure the environment is quiet and the room temperature is constant.</li>
		<li>Give rats 30 min to adapt to the testing environment.</li>
		<li>Calibrate the thermal stimulus via the infrared radiometer. Set the desired infrared intensity at 70 units.</li>
		<li>Place the infrared emitter/detector on the container directly under the center of the paw being tested.</li>
		<li>Pressing the START button. The timer will start automatically. The controller will automatically turn off the infrared light and stop the timer altogether as soon as movement of the paw occurs.</li>
		<li>Record the reaction time when the appearance of paw withdrawal and paw licking. 
		NOTE: A positive response for the test is regarded as paw withdrawal and paw licking. If only paw withdrawal occurs, it should be regarded as a voluntary movement of the rat rather than a positive response.</li>
		<li>Repeat the test more than three times. Average the data as the TWL of rats. 
		NOTE: Each exposure of radiant heat should not exceed 20 s. Infrared stimulations on the same hind paw should be at least 3&#8722;5 min apart.</li>
	</ol>
	</li>
	<li>Gait pattern analyses 
	NOTE: The gait pattern analyses were measured using an imaging system (Table of Materials) and the observer was blinded to the injections that the animals had received.
	<ol>
		<li>Adjust the length of the walking compartment by using the knobs at both ends of the walking compartment to suitable length for rats (e.g., 61 cm).</li>
		<li>Place a rat into the walking compartment and train rats to make uninterrupted runs for at least 5 step-cycles at a speed of at 18 cm/s before the formal experiment. 
		NOTE: When a rat is first placed in the walking compartment, the speed can be set to about 20 cm/s and shut off when running around 2 s. Then set the speed to 18 cm/s. Gently tap the back of the rat with the partition, if the rat pauses or retreats during walking. Try to reduce the speed gradually from 18 cm/s to 10 cm/s. If the rat eventually fails to perform the test, it is acceptable to choose another rat for the test.</li>
		<li>Slowly increase the speed of the treadmill until it reaches the target speed (18 cm/s). Capture at least 5 s video of continuous movement of the rat with the high-speed digital video camera mounted below the transparent treadmill belt.</li>
		<li>Test each rat at least 5 min apart to obtain at least three uninterrupted runs.</li>
		<li>Draw a &#8220;bounding box&#8221; to define the boundary of animal walking image in the imaging software and enter the run speed for each video. Select videos as a group and process videos automatically by the software. After processing videos, the software will output several spreadsheets to report gait indices, including stance, swing, braking, propulsion, cadence, step sequence, etc.</li>
		<li>Calculate total paw area (cm2), average stride length (cm), and unite stride length. 
		NOTE: Total paw area is the mean of the total area of four paws of each group of rats and paw area is defined as the maximal paw area in contact with the treadmill during the stance phase of the step cycle. Stride length is the distance between initial contacts of the same paw in one complete stride. Unit stride length = average stride length (cm)/body length (cm).&#160;</li>
	</ol>
	</li>
</ol>
3. Histopathological and immunohistochemical analyses
<ol>
	<li>Euthanize rats by intraperitoneal injection of pentobarbital sodium at 150 mg/kg (prepared in saline). Resect the&#160;knee joints immediately for the histologic analyses.</li>
	<li>Fix the joints in 10% formalin for 24 h, decalcify with 10% EDTA in phosphate buffered saline (PBS) for 8 weeks, and then embed joints in paraffin. 
	CAUTION: Formalin can cause eye, skin, and respiratory tract irritation. It should be handled in a hood.</li>
	<li>Section the paraffin embedded joints at 3 mm thickness with a microtome and float in a 40 &#176;C water bath containing distilled water.</li>
	<li>Transfer sections onto glass slides. Dry slides overnight and store slides at room temperature (RT) to continue the following staining.</li>
	<li>Place slides in a 60 &#176;C oven for 4 h to deparaffinize.</li>
	<li>Immerse the slides successively in xylene, xylene, 100% ethanol, 100% ethanol, 95% ethanol, 80% ethanol and 75% ethanol for 5 min, respectively, at RT.</li>
	<li>Stain sections with hematoxylin and eosin (H&#38;E), safranin-O (SO) and Alcian blue hematoxylin (ABH) as well as antibodies against rat type II collagen (Col2), type X collagen (Col10) and matrix metalloproteinase 13 (MMP13), as described in steps 3.8&#8722;3.12.</li>
	<li>H&#38;E staining
	<ol>
		<li>Rinse slides with deionized H2O for 3 min. Stain slides with hematoxylin for 3&#8722;5 min.</li>
		<li>Rinse slides with deionized H2O 3x, 1 min each, until no hematoxylin remains on the surface.</li>
		<li>Stain slides with eosin for 30 s. Then, rinse slides with deionized H2O 3x, 1 min each, until no eosin remains on the surface.</li>
		<li>Immerse slides in 0.1% ammonia for 10&#8722;20 s. Then, rinse slides with deionized H2O 3x, 1 min each.</li>
		<li>Immerse slides successively in 95% ethanol, 100% ethanol, xylene, xylene and xylene for 1 min, respectively.</li>
		<li>Coverslip the slides by neutral resin.</li>
	</ol>
	</li>
	<li>SO staining
	<ol>
		<li>Rinse slides with deionized H2O for 3 min. Stain slides with hematoxylin for 3&#8722;5 min.</li>
		<li>Differentiate quickly in 1% acid alcohol (about 3 s). Then, rinse slides with deionized H2O 3x, 1 min each, until no hematoxylin remains on the surface.</li>
		<li>Stain slides with Fast Green (FCF) solution for 5 min. Then, rinse slides with deionized H2O 3x, 1 min each.</li>
		<li>Stain slides with SO for 1&#8722;2 min. Then, rinse slides with deionized H2O 3x, 1 min each.</li>
		<li>Rinse slides with 1% acetic acid for 1&#8722;2 min to remove the residual FCF. Rinse slides with deionized H2O for 1 min.</li>
		<li>Immerse slides successively in 95% ethanol, 100% ethanol, xylene, xylene and xylene for 1 min, respectively.</li>
		<li>Coverslip the slides by neutral resin.</li>
	</ol>
	</li>
	<li>ABH staining
	<ol>
		<li>Rinse slides with deionized H2O for 3 min. Immerse slides in 1% acid alcohol for 30 s and drain briefly on a paper towel (do not rinse).</li>
		<li>Immerse slides in ABH for 1 h. Then, rinse slides with deionized H2O 3x, 1 min each, until no ABH remains on the surface.</li>
		<li>Differentiate quickly in 1% acid alcohol (about 3 s). Rinse slides with deionized H2O 3x, 1 min each.</li>
		<li>Immerse slides in 0.5% ammonium water for 15 s. Then, rinse slides with deionized H2O 3x, 1 min each.</li>
		<li>Immerse slides in 95% ethanol for 1 min. Immerse slides in eosin/orange G solution for 1.5 min.</li>
		<li>Immerse slides successively in 95% ethanol, 100% ethanol, xylene, xylene and xylene for 1 min, respectively.</li>
		<li>Coverslip the slides by neutral resin.</li>
	</ol>
	</li>
	<li>Examine all slides under a microscope and statistically grade on a scale of 0&#8722;13 by double-blind observation, according to Mankin&#8217;s scoring system14.</li>
	<li>Immunohistochemistry
	<ol>
		<li>Rinse slides with deionized H2O for 3 min.</li>
		<li>Immerse slides in 0.1 M sodium citrate and place slides in a 60 &#176;C oven for 4 h to retrieve the antigen.</li>
		<li>Immerse slides in 0.3% Triton X-100 in PBS for 10 min. Then, rinse slides with PBS 2x, 3 min each.</li>
		<li>Incubate sections in 3% H2O2 solution in methanol at RT for 10 min to block endogenous peroxidase activity. Rinse slides with PBS 2x, 3 min each.</li>
		<li>Incubate sections with 5% goat serum in PBS for 30 min at RT to block any non-specific binding. Rinse slides with PBS 2x, 3 min each.</li>
		<li>Incubate sections overnight at 4 &#176;C with 100 &#181;L of PBS-diluted (1:1,000) primary antibodies against rat type II collagen (Col2), type X collagen (Col10) and matrix metalloproteinase 13 (MMP13). Rinse slides with PBS 2x, 3 min each.</li>
		<li>Incubate sections with 100 &#181;L of PBS-diluted (1:1,000) secondary antibody (goat anti-mouse secondary or goat anti-mouse secondary) for 20 min at RT. Rinse slides with PBS 2x, 3 min each.</li>
		<li>Incubate sections with 100 &#181;L of 3,3&#8242;-diaminobenzidine (DAB) working solution. Monitor the reaction as the chromogenic reaction turns the epitope sites brown. 
		CAUTION: DAB is a carcinogen. Always wear gloves and work in a hood when working with DAB. 
		NOTE: The time of color development may vary from a few seconds to 10 min.</li>
		<li>As soon as a brown color develops on the sections, rinse slides with deionized H2O 2x, 3 min each.</li>
		<li>Immerse slides in hematoxylin for 1&#8722;2 min to counterstain slides. Then, rinse slides with deionized H2O 3x, 1 min each.</li>
		<li>Immerse slides successively in 95% ethanol, 100% ethanol, xylene, xylene and xylene for 1 min, respectively.</li>
		<li>Coverslip the slides by neutral resin.</li>
		<li>Observe the color of the antibody staining in the sections under a microscope.</li>
	</ol>
	</li>
</ol>

<ol><li>Hunter, D. J., Schofield, D., Callander, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((The+individual+and+socioeconomic+impact+of+osteoarthritis%5BTitle%5D)+AND+%22Nature+Reviews+Rheumatology%22%5BJournal%5D)">The individual and socioeconomic impact of osteoarthritis.</a> Nature Reviews Rheumatology. 10 (7), 437-441 (2014).</li>
<li>Neogi, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((The+epidemiology+and+impact+of+pain+in+osteoarthritis%5BTitle%5D)+AND+%22Osteoarthritis+and+Cartilage%22%5BJournal%5D)">The epidemiology and impact of pain in osteoarthritis.</a> Osteoarthritis and Cartilage. 21 (9), 1145-1153 (2013).</li>
<li>Teeple, E., Jay, G. D., Elsaid, K. A., Fleming, B. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Animal+models+of+osteoarthritis%3A+challenges+of+model+selection+and+analysis%5BTitle%5D)+AND+%22AAPS+Journal%22%5BJournal%5D)">Animal models of osteoarthritis: challenges of model selection and analysis.</a> AAPS Journal. 15 (2), 438-446 (2013).</li>
<li>Woolf, A. D., Pfleger, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Burden+of+major+musculoskeletal+conditions%5BTitle%5D)+AND+%22Bulletin+of+the+World+Health+Organization%22%5BJournal%5D)">Burden of major musculoskeletal conditions.</a> Bulletin of the World Health Organization. 81 (9), 646-656 (2003).</li>
<li>Bijlsma, J. W., Berenbaum, F., Lafeber, F. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Osteoarthritis%3A+an+update+with+relevance+for+clinical+practice%5BTitle%5D)+AND+%22Lancet%22%5BJournal%5D)">Osteoarthritis: an update with relevance for clinical practice.</a> Lancet. 377 (9783), 2115-2126 (2011).</li>
<li>McCoy, A. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Animal+Models+of+Osteoarthritis%3A+Comparisons+and+Key+Considerations%5BTitle%5D)+AND+%22Veterinary+Pathology%22%5BJournal%5D)">Animal Models of Osteoarthritis: Comparisons and Key Considerations.</a> Veterinary Pathology. 52 (5), 803-818 (2015).</li>
<li>O'Neill, T. W., Felson, D. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Mechanisms+of+Osteoarthritis+%28OA%29+Pain%5BTitle%5D)+AND+%22Current+Osteoporosis+Reports%22%5BJournal%5D)">Mechanisms of Osteoarthritis (OA) Pain.</a> Current Osteoporosis Reports. 16 (5), 611-616 (2018).</li>
<li>Kuyinu, E. L., Narayanan, G., Nair, L. S., Laurencin, C. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Animal+models+of+osteoarthritis%3A+classification%2C+update%2C+and+measurement+of+outcomes%5BTitle%5D)+AND+%22Journal+of+Orthopaedic+Surgery+and+Research%22%5BJournal%5D)">Animal models of osteoarthritis: classification, update, and measurement of outcomes.</a> Journal of Orthopaedic Surgery and Research. 11, 19(2016).</li>
<li>Takahashi, I., Matsuzaki, T., Hoso, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Long-term+histopathological+developments+in+knee-joint+components+in+a+rat+model+of+osteoarthritis+induced+by+monosodium+iodoacetate%5BTitle%5D)+AND+%22Journal+of+Physical+Therapy+Science%22%5BJournal%5D)">Long-term histopathological developments in knee-joint components in a rat model of osteoarthritis induced by monosodium iodoacetate.</a> Journal of Physical Therapy Science. 29 (4), 590-597 (2017).</li>
<li>Liu, P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Ongoing+pain+in+the+MIA+model+of+osteoarthritis%5BTitle%5D)+AND+%22Neuroscience+Letters%22%5BJournal%5D)">Ongoing pain in the MIA model of osteoarthritis.</a> Neuroscience Letters. 493 (3), 72-75 (2011).</li>
<li>Combe, R., Bramwell, S., Field, M. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((The+monosodium+iodoacetate+model+of+osteoarthritis%3A+a+model+of+chronic+nociceptive+pain+in+rats%5BTitle%5D)+AND+%22Neuroscience+Letters%22%5BJournal%5D)">The monosodium iodoacetate model of osteoarthritis: a model of chronic nociceptive pain in rats.</a> Neuroscience Letters. 370 (2-3), 236-240 (2004).</li>
<li>Pomonis, J. D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Development+and+pharmacological+characterization+of+a+rat+model+of+osteoarthritis+pain%5BTitle%5D)+AND+%22Pain%22%5BJournal%5D)">Development and pharmacological characterization of a rat model of osteoarthritis pain.</a> Pain. 114 (3), 339-346 (2005).</li>
<li>Chaplan, S. R., Bach, F. W., Pogrel, J. W., Chung, J. M., Yaksh, T. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Quantitative+assessment+of+tactile+allodynia+in+the+rat+paw%5BTitle%5D)+AND+%22Journal+of+Neuroscience+Methods%22%5BJournal%5D)">Quantitative assessment of tactile allodynia in the rat paw.</a> Journal of Neuroscience Methods. 53 (1), 55-63 (1994).</li>
<li>Mankin, H. J., Dorfman, H., Lippiello, L., Zarins, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Biochemical+and+metabolic+abnormalities+in+articular+cartilage+from+osteo-arthritic+human+hips.+II.+Correlation+of+morphology+with+biochemical+and+metabolic+data%5BTitle%5D)+AND+%22Journal+of+Bone+and+Joint+Surgery%22%5BJournal%5D)">Biochemical and metabolic abnormalities in articular cartilage from osteo-arthritic human hips. II. Correlation of morphology with biochemical and metabolic data.</a> Journal of Bone and Joint Surgery. 53 (3), 523-537 (1971).</li>
<li>Yan, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Chondroprotective+effects+of+platelet+lysate+towards+monoiodoacetate-induced+arthritis+by+suppression+of+TNF-%CE%B1-induced+activation+of+NF-%C4%B8B+pathway+in+chondrocytes%5BTitle%5D)+AND+%22Aging%22%5BJournal%5D)">Chondroprotective effects of platelet lysate towards monoiodoacetate-induced arthritis by suppression of TNF-α-induced activation of NF-ĸB pathway in chondrocytes.</a> Aging. 11 (9), 2797-2811 (2019).</li>
<li>Yan, B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Intra-Articular+Injection+of+Extract+Attenuates+Pain+Behavior+and+Cartilage+Degeneration+in+Mono-Iodoacetate+Induced+Osteoarthritic+Rats%5BTitle%5D)+AND+%22Frontiers+in+Pharmacology%22%5BJournal%5D)">Intra-Articular Injection of Extract Attenuates Pain Behavior and Cartilage Degeneration in Mono-Iodoacetate Induced Osteoarthritic Rats.</a> Frontiers in Pharmacology. 9, 1360(2018).</li>
<li>Wang, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Agkistrodon+ameliorates+pain+response+and+prevents+cartilage+degradation+in+monosodium+iodoacetate-induced+osteoarthritic+rats+by+inhibiting+chondrocyte+hypertrophy+and+apoptosis%5BTitle%5D)+AND+%22Journal+of+Ethnopharmacology%22%5BJournal%5D)">Agkistrodon ameliorates pain response and prevents cartilage degradation in monosodium iodoacetate-induced osteoarthritic rats by inhibiting chondrocyte hypertrophy and apoptosis.</a> Journal of Ethnopharmacology. 231, 545-554 (2019).</li>
<li>Yamada, E. F., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Evaluation+of+monosodium+iodoacetate+dosage+to+induce+knee+osteoarthritis%3A+Relation+with+oxidative+stress+and+pain%5BTitle%5D)+AND+%22International+Journal+of+Rheumatic+Diseases%22%5BJournal%5D)">Evaluation of monosodium iodoacetate dosage to induce knee osteoarthritis: Relation with oxidative stress and pain.</a> International Journal of Rheumatic Diseases. 22 (3), 399-410 (2019).</li>
<li>Schuelert, N., McDougall, J. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Electrophysiological+evidence+that+the+vasoactive+intestinal+peptide+receptor+antagonist+VIP6-28+reduces+nociception+in+an+animal+model+of+osteoarthritis%5BTitle%5D)+AND+%22Osteoarthritis+and+Cartilage%22%5BJournal%5D)">Electrophysiological evidence that the vasoactive intestinal peptide receptor antagonist VIP6-28 reduces nociception in an animal model of osteoarthritis.</a> Osteoarthritis and Cartilage. 14 (11), 1155-1162 (2006).</li>
<li>Lee, S. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Choline%2C+an+alpha7+nicotinic+acetylcholine+receptor+agonist%2C+alleviates+hyperalgesia+in+a+rat+osteoarthritis+model%5BTitle%5D)+AND+%22Neuroscience+Letters%22%5BJournal%5D)">Choline, an alpha7 nicotinic acetylcholine receptor agonist, alleviates hyperalgesia in a rat osteoarthritis model.</a> Neuroscience Letters. 548, 291-295 (2013).</li>
<li>Piesla, M. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Abnormal+gait%2C+due+to+inflammation+but+not+nerve+injury%2C+reflects+enhanced+nociception+in+preclinical+pain+models%5BTitle%5D)+AND+%22Brain+Research%22%5BJournal%5D)">Abnormal gait, due to inflammation but not nerve injury, reflects enhanced nociception in preclinical pain models.</a> Brain Research. 1295, 89-98 (2009).</li>
<li>Udo, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Monoiodoacetic+acid+induces+arthritis+and+synovitis+in+rats+in+a+dose-+and+time-dependent+manner%3A+proposed+model-specific+scoring+systems%5BTitle%5D)+AND+%22Osteoarthritis+and+Cartilage%22%5BJournal%5D)">Monoiodoacetic acid induces arthritis and synovitis in rats in a dose- and time-dependent manner: proposed model-specific scoring systems.</a> Osteoarthritis and Cartilage. 24 (7), 1284-1291 (2016).</li>
<li>Guingamp, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Mono-iodoacetate-induced+experimental+osteoarthritis%3A+a+dose-response+study+of+loss+of+mobility%2C+morphology%2C+and+biochemistry%5BTitle%5D)+AND+%22Arthritis+%26+Rheumatism%22%5BJournal%5D)">Mono-iodoacetate-induced experimental osteoarthritis: a dose-response study of loss of mobility, morphology, and biochemistry.</a> Arthritis & Rheumatism. 40 (9), 1670-1679 (1997).</li>
<li>Jeong, J. H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Eupatilin+Exerts+Antinociceptive+and+Chondroprotective+Properties+in+a+Rat+Model+of+Osteoarthritis+by+Downregulating+Oxidative+Damage+and+Catabolic+Activity+in+Chondrocytes%5BTitle%5D)+AND+%22PLoS+ONE%22%5BJournal%5D)">Eupatilin Exerts Antinociceptive and Chondroprotective Properties in a Rat Model of Osteoarthritis by Downregulating Oxidative Damage and Catabolic Activity in Chondrocytes.</a> PLoS ONE. 10 (6), 0130882(2015).</li>
<li>Cook, J. L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Animal+models+of+cartilage+repair%5BTitle%5D)+AND+%22Bone+%26+Joint+Research%22%5BJournal%5D)">Animal models of cartilage repair.</a> Bone & Joint Research. 3 (4), 89-94 (2014).</li>
<li>Little, C. B., Zaki, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((What+constitutes+an+%22animal+model+of+osteoarthritis%22--the+need+for+consensus%5BTitle%5D)+AND+%22Osteoarthritis+and+Cartilage%22%5BJournal%5D)">What constitutes an "animal model of osteoarthritis"--the need for consensus.</a> Osteoarthritis and Cartilage. 20 (4), 261-267 (2012).</li>
</ol>

The authors have nothing to disclose.

The rat model of OA induced by MIA is a well-established, widely used model. Intra-articular injection of MIA initially causes severe and acute inflammation, which gives rise to the longer and degenerative phase of OA17,18. In this research, we measured nociceptive sensitivity by MWT and TWL, and assessed gait alterations with an imaging system. Previous reports found that the injection of MIA could raise the sensitivity of afferent knee joint fibers leading to n...

Osteoarthritis (OA) is the most common joint disease in the world, affecting an estimated 10-12% populations in adults1. The most generally involved joint is the knee, and OA has a higher incidence in older adults, especially women2. As a chronic disease, OA develops progressively over decades into joint failure with symptoms such as cartilage loss, synovial inflammation, osteophytosis, decreased function, and chronic pain3. According to the World Health Organization (WHO), OA is the fourth most prevalent disease in females and the eighth most prevalent disease in males. By 2020, OA may become the fourth most disabling disease in humans4. However, currently available therapies of OA address only symptoms and extend the time until joint replacement surgery5.
The spontaneous OA in human patients often takes a long time to produce clinical symptoms such as joint related pain6. In the early stages of OA, pain is usually intermittent and becomes more frequent and severe as the disease progresses, making it the predominant complaint of patients7. Therefore, extensive animal models for OA pain have been developed over the past half century to promote pain relief therapy. OA models have classically been divided into spontaneous and induced models. Spontaneous models include naturally occurring models and genetically modified models, which can more closely simulate the course of primary OA in humans8. Induced models can generally be divided into two categories: 1) post-traumatic OA induced by surgery or other trauma; or 2) intra-articular injection of chondrotoxic or pro-inflammatory substances3. These models lay a foundation for the pathophysiological study of OA and contribute greatly to the development of drugs to reduce pain and increase function.
Recently, the most widely used inducer for OA modeling is mono-iodoacetate (MIA). MIA, an inhibitor of glyceraldehyde-3-phosphate dehydrogenase, can cause changes in cartilage matrix, degradation, loss of cartilage, synovitis and other changes, which are similar to the pathological changes of human osteoarthritis9. It has been noted that intra-articular injection of MIA induced ongoing pain at 28 days after MIA administration, indicating that the MIA model may be useful for investigating chronic nociceptive pain10,11,12. In this study, male Sprague-Dawley rats received intra-articular injections with 0.5, 1.5, or 3 mg of MIA in the knee joints. The severity of MIA-induced joint pain was measured by assessment of mechanical and thermal sensitivity at 1, 7, 14, 21, 28 and 35 days after injections. On this basis, 1.5 mg of MIA was selected as the final concentration to evaluate gait patterns and histological changes at 28 days after injections.

<table><tbody><tr><td>Anti-Collagen II antibody</td><td>Abcam(UK)</td><td>34712</td><td>Primary antibody for immunohistochemistry (IHC)</td></tr><tr><td>Anti-Collagen X (Col10) antibody</td><td>Abcam(UK)</td><td>49945</td><td>Primary antibody for IHC</td></tr><tr><td>DigiGait Imaging System</td><td>Mouse Specifics (Boston, MA, USA)</td><td></td><td>Equipment for gait patterns analyses</td></tr><tr><td>Eosin</td><td>Sigma-Aldrich</td><td>861006</td><td>The dye for HE staining</td></tr><tr><td>Fast Green FCF</td><td>Sigma-Aldrich</td><td>F7252</td><td>The dye for SO staining</td></tr><tr><td>Goat anti-mouse antibody</td><td>ZSGQ-BIO (Beijing, China)</td><td>PV-9002</td><td>Secondary antibody for IHC</td></tr><tr><td>Goat anti-rabbit antibody</td><td>ZSGQ-BIO (Beijing, China)</td><td>PV-9001</td><td>Secondary antibody for IHC</td></tr><tr><td>Hematoxylin</td><td>Sigma-Aldrich</td><td>H3163</td><td>The dye for HE staining</td></tr><tr><td>MIA</td><td>Sigma-Aldrich</td><td>I4386-10G</td><td>powder</td></tr><tr><td>MMP13</td><td>Cell Signaling Technology, Inc. (Danvers, MA, USA)</td><td>69926</td><td>Primary antibody for IHC</td></tr><tr><td>Modular tissue embedding center</td><td>Thermo Fisher Scientific (USA)</td><td>EC 350</td><td>Produce paraffin blocks.</td></tr><tr><td>Plantar Test apparatus</td><td>UgoBasile (Italy)</td><td>37370</td><td>Equipment for TWL assay</td></tr><tr><td>PrimeScript RT reagent Kit (Perfect Real Time)</td><td>TaKaRa Biotechnology Co. Ltd. (Dalian, China)</td><td>RR037A</td><td>Extracte total RNA from cultured cells</td></tr><tr><td>Rotary and Sliding Microtomes</td><td>Thermo Fisher Scientific (USA)</td><td>HM325</td><td>Precise paraffin sections.</td></tr><tr><td>Safranin-O</td><td>Sigma-Aldrich</td><td>S2255</td><td>The dye for SO staining</td></tr><tr><td>Tissue-Tek VIP 5 Jr</td><td>Sakura (Japan)</td><td></td><td>Vacuum Infiltration Processor</td></tr></tbody></table>

osteoarthritis pain model induced by intra-articular injection of mono-iodoacetate in rats

The current animal models of osteoarthritis (OA) can be divided into spontaneous models and induced models, both of which aim to simulate the pathophysiological changes of human OA. However, as the main symptom in the late stage of OA, pain affects the patients&#39; daily life, and there are not many available models. The mono-iodoacetate (MIA)-induced model is the most widely used OA pain model, mainly used in rodents. MIA is an inhibitor of glyceraldehyde-3-phosphate dehydrogenase, which causes chondrocyte death, cartilage degeneration, osteophyte, and measurable changes in animal behavior. Besides, expression changes of matrix metalloproteinase (MMP) and pro-inflammatory cytokines (IL1 &#946; and TNF &#945;) can be detected in the MIA-induced model. Those changes are consistent with OA pathophysiological conditions in humans, indicating that MIA can induce a measurable and successful OA pain model. This study aims to describe the methodology of intra-articular injection of MIA in rats and discuss the resulting pain-related behaviors and histopathological changes.

With this methodology, we established an OA pain model in the rat and detected the resulting changes. MWT and TWL reflected mechanical allodynia and thermal hyperalgesia, respectively. As shown in Figure 1, MIA induced mechanical allodynia and thermal hyperalgesia present in a dose-dependent manner. Remarkably, the decrease of MWT reached a peak from 21 days to 28 days, and then rebounded, suggesting that joint repair may occur at this stage, but MWT of 3 mg MIA group was still at a low leve...

Watch this Scientific Journal Video about Osteoarthritis Pain Model Induced by Intra-Articular Injection of Mono-Iodoacetate in Rats at JoVE.com

Osteoarthritis Pain Model Induced by Intra-Articular Injection of Mono-Iodoacetate in Rats

This study describes the method of intra-articular injection of mono-iodoacetate in rats and discusses the resulting pain-related behaviors and histopathological changes, which provide references for future applications.

The current animal models of osteoarthritis (OA) can be divided into spontaneous models and induced models, both of which aim to simulate the ...

osteoarthritis-pain-model-induced-intra-articular-injection-mono

Universidad de Cartagena UDEC

Research

JoVE Journal

Medicine

8.2K Views.  Zhejiang Chinese Medical University. This study describes the method of intra-articular injection of mono-iodoacetate in rats and discusses the resulting pain-related behaviors and histopathological changes, which provide references for future applications.

Video: Osteoarthritis Pain Model Induced by Intra-Articular Injection of Mono-Iodoacetate in Rats

Chronic Constriction of the Sciatic Nerve and Pain Hypersensitivity Testing in Rats

Chronic neuropathic pain, resulting from damage to the central or peripheral nervous system, is a prevalent and debilitating condition, affecting 7-18% of the population1,2. Symptoms include spontaneous (tingling, burning, electric-shock like) pain, dysaesthesia, paraesthesia, allodynia (pain resulting from normally non-painful stimuli) and hyperalgesia (an increased response to painful stimuli). The sensory symptoms are co-morbid with behavioural disabilities, such as insomnia and depression. To study chronic neuropathic pain several animal models mimicking peripheral nerve injury have been developed, one of the most widely used is Bennett and Xie's (1988) unilateral sciatic nerve chronic constriction injury (CCI)3 (Figure 1). Here we present a method for performing CCI and testing pain hypersensitivity.
CCI is performed under anaesthesia, with the sciatic nerve on one side exposed by making a skin incision, and cutting through the connective tissue between the gluteus superficialis and biceps femoris muscles. Four chromic gut ligatures are tied loosely around the sciatic nerve at 1 mm intervals, to just occlude but not arrest epineural blood flow. The wound is closed with sutures in the muscle and staples in the skin. The animal is then allowed to recover from surgery for 24 hrs before pain hypersensitivity testing begins.
For behavioural testing, rats are placed into the testing apparatus and are allowed to habituate to the testing procedure. The area tested is the mid-plantar surface of the hindpaw (Figure 2), which falls within the sciatic nerve distribution. Mechanical withdrawal threshold is assessed by mechanically stimulating both injured and uninjured hindpaws using an electronic dynamic plantar von Frey aesthesiometer or manual von Frey hairs4. The mechanical withdrawal threshold is the maximum pressure exerted (in grams) that triggers paw withdrawal. For measurement of thermal withdrawal latency, first described by Hargreaves et al (1988), the hindpaw is exposed to a beam of radiant heat through a transparent glass surface using a plantar analgesia meter5,6. The withdrawal latency to the heat stimulus is recorded as the time for paw withdrawal in both injured and uninjured hindpaws. Following CCI, mechanical withdrawal threshold, as well as thermal withdrawal latency in the injured paw are both significantly reduced, compared to baseline measurements and the uninjured paw (Figure 3). The CCI model of peripheral nerve injury combined with pain hypersensitivity testing provides a model system to investigate the effectiveness of potential therapeutic agents to modify chronic neuropathic pain. In our laboratory, we utilise CCI alongside thermal and mechanical sensitivity of the hindpaws to investigate the role of neuro-immune interactions in the pathogenesis and treatment of neuropathic pain.

Due to the simplicity of surgery and the robust behavioural outcome, chronic constriction of the sciatic nerve is one of the pre-eminent animal models of neuropathic pain. Within 24 hrs following surgery, pain hypersensitivity is established and can be quantitatively measured using a von Frey aesthesiometer (mechanical test) and plantar analgesia meter (thermal test).

Chronic neuropathic pain, resulting from damage to the central or peripheral nervous system, is a prevalent and debilitating condition, affecting 7-18% of ...

Retinal Detachment Model in Rodents by Subretinal Injection of Sodium Hyaluronate

Subretinal injection of sodium hyaluronate is a widely accepted method of inducing retinal detachment (RD). However, the height and duration of RD or the occurrence of subretinal hemorrhage can affect photoreceptor cell death in the detached retina. Hence, it is advantageous to create reproducible RDs without subretinal hemorrhage for evaluating photoreceptor cell death. We modified a previously reported method to create bullous and persistent RDs in a reproducible location with rare occurrence of subretinal hemorrhage. The critical step of this modified method is the creation of a self-sealing scleral incision, which can prevent leakage of sodium hyaluronate after injection into the subretinal space. To make the self-sealing scleral incision, a scleral tunnel is created, followed by scleral penetration into the choroid with a 30 G needle. Although choroidal hemorrhage may occur during this step, astriction with a surgical spear reduces the rate of choroidal hemorrhage. This method allows a more reproducible and reliable model of photoreceptor death in diseases that involve RD such as rhegmatogenous RD, retinopathy of prematurity, diabetic retinopathy, central serous chorioretinopathy, and age-related macular degeneration (AMD).

Creating experimental retinal detachments with a reproducible and sustained height of detachment, and without subretinal hemorrhage, is important for studying the pathophysiology of photoreceptor cell loss in retinal disease and evaluating potential therapeutic interventions. Here, we report such a method in detail.

Subretinal injection of sodium hyaluronate is a widely accepted method of inducing retinal detachment (RD). However, the height and duration of RD or the ...

Experimental Glaucoma Induced by Ocular Injection of Magnetic Microspheres

Progress in understanding the pathophysiology, and providing novel treatments for glaucoma is dependent on good animal models of the disease. We present here a protocol for elevating intraocular pressure (IOP) in the rat, by injecting magnetic microspheres into the anterior chamber of the eye. The use of magnetic particles allows the user to manipulate the beads into the iridocorneal angle, thus providing a very effective blockade of fluid outflow from the trabecular meshwork. This leads to long-lasting IOP rises, and eventually neuronal death in the ganglion cell layer (GCL) as well as optic nerve pathology, as seen in patients with the disease. This method is simple to perform, as it does not require machinery, specialist surgical skills, or many hours of practice to perfect. Furthermore, the pressure elevations are very robust, and reinjection of the magnetic microspheres is not usually required unlike in some other models using plastic beads. Additionally, we believe this method is suitable for adaptation for the mouse eye.

We present a method for inducing elevated intraocular pressure (IOP), by injecting magnetic microspheres into the rat eye, to model glaucoma. This leads to strong pressure rises, and extensive neuronal death. This protocol is easy to perform, does not require repeat injections, and produces stable long-lasting IOP rises.

Progress in understanding the pathophysiology, and providing novel treatments for glaucoma is dependent on good animal models of the disease. We present ...

Inflammatory TMJ Pain Mouse Model: Bite Force and Von Frey Filament Assessments

Temporomandibular Joint Pain Measurement by Bite Force and Von Frey Filament Assays in Mice

Temporomandibular joint (TMJ) pain and osteoarthritis (OA) are common and debilitating disorders that impair patients' quality of life. The mechanisms driving diseases-related pain are poorly understood, and current treatments fail to provide effective and long-term therapeutic effects. Additionally, pain assessment in research, particularly orofacial pain, poses several challenges that complicate studies in both clinical and basic science settings. Therefore, we have established an inflammatory TMJ pain mouse model via intra-articular injection of CFA (Complete Freund's Adjuvant) and evaluated pain behaviors by bite force measurement and the von Frey filament test. Mice with CFA injection exhibited orofacial pain behaviors compared to PBS injection, including reduced bite force and head withdrawal threshold in the von Frey filament test. These methods are relatively easy to execute to have reproducible results and can be potentially extended to pain studies for other disease models related to TMJ disorders. Together, bite force, and the von Frey filament tests are reliable in measuring orofacial pain, as demonstrated in CFA injection-induced painful TMJOA mouse models.

This protocol describes how measuring bite force and head withdrawal threshold can capture pain behavior in Complete Freund's Adjuvant (CFA)-induced inflammatory temporomandibular joint (TMJ) pain.

Temporomandibular joint (TMJ) pain and osteoarthritis (OA) are common and debilitating disorders that impair patients' quality of life. The mechanisms ...

Behavior

The Monoiodoacetate Model of Osteoarthritis Pain in the Mouse

A major symptom of patients with osteoarthritis (OA) is pain that&#160;is triggered by peripheral as well as central changes within the pain pathways. The current treatments for OA pain such as NSAIDS or opiates are neither sufficiently effective nor devoid of detrimental side effects. Animal models of OA are being developed to improve our understanding of OA-related pain mechanisms and define novel pharmacological targets for therapy. Currently available models of OA in rodents include surgical and chemical interventions into one knee joint. The monoiodoacetate (MIA) model has become a standard for modelling joint disruption in OA in both rats and mice. The model, which is easier to perform in the rat, involves injection of MIA into a knee joint that induces rapid pain-like responses in the ipsilateral limb, the level of which can be controlled by injection of different doses. Intra-articular injection of MIA disrupts chondrocyte glycolysis by inhibiting glyceraldehyde-3-phosphatase dehydrogenase and results in chondrocyte death, neovascularization, subchondral bone necrosis and collapse, as well as inflammation. The morphological changes of the articular cartilage and bone disruption are reflective of some aspects of patient pathology. Along with joint damage, MIA injection induces referred mechanical sensitivity in the ipsilateral hind paw and weight bearing deficits that are measurable and quantifiable. These behavioral changes resemble some of the symptoms reported by the patient population, thereby validating the MIA injection in the knee as a useful and relevant pre-clinical model of OA pain.
The aim of this article is to describe the methodology of intra-articular injections of MIA and the behavioral recordings of the associated development of hypersensitivity with a mind to highlight the necessary steps to give consistent and reliable recordings.

Osteoarthritis (OA), or degenerative joint disease, is a debilitating condition associated with pain that remains only partially controlled by available analgesics. Animal models are being developed to improve our understanding of OA-related pain mechanisms. Here we describe the methodology for the monoiodoacetate model of OA pain in the mouse.

A major symptom of patients with osteoarthritis (OA) is pain that&#160;is triggered by peripheral as well as central changes within the pain pathways. The ...

A Model of Glaucoma Induced by Circumlimbal Suture in Rats and Mice

The circumlimbal suture is a technique for inducing experimental glaucoma in rodents by chronically elevating intraocular pressure (IOP), a well-known risk factor for glaucoma. This protocol demonstrates a step-by-step guide on this technique in Long Evans rats and C57BL/6 mice. Under general anesthesia, a "purse-string" suture is applied on the conjunctiva, around the equator and behind the limbus of the eye. The fellow eye serves as an untreated control. Over the duration of our study, which was a period of 8 weeks for rats and 12 weeks for mice, IOP remained elevated, as measured regularly by rebound tonometry in conscious animals without topical anesthesia. In both species, the sutured eyes showed electroretinogram features consistent with preferential inner retinal dysfunction. Optical coherence tomography showed selective thinning of the retinal nerve fiber layer. Histology of the rat retina in cross-section found reduced cell density in the ganglion cell layer, but no change in other cellular layers. Staining of flat-mounted mouse retinae with a ganglion cell specific marker (RBPMS) confirmed ganglion cell loss. The circumlimbal suture is a simple, minimally invasive and cost-effective way to induce ocular hypertension that leads to ganglion cell injury in both rats and mice.

Chronic ocular hypertension is induced by applying a circumlimbal suture in rats and mice, leading to functional and structural deterioration of the retinal ganglion cells consistent with glaucoma.

The circumlimbal suture is a technique for inducing experimental glaucoma in rodents by chronically elevating intraocular pressure (IOP), a well-known ...

Spontaneous and Evoked Measures of Pain in Murine Models of Monoarticular Knee Pain

Pain is the main cause of disability from arthritis. There is currently an unmet need for adequate treatments for arthritis pain. Pre-clinical models are necessary and useful for studying the mechanisms of pain and for evaluating efficacy of arthritis therapies. Measuring pain in animal models of arthritis is challenging. We have developed methods for measuring evoked and spontaneous pain in three models of murine arthritis. We quantitate the evoked pain responses of mice subjected to firm palpation of a painful knee. We also evaluate spontaneous pain by the proportion of weight and the amount of time placed on each of their 4 limbs after induction of arthritis pain in one knee. Joint pain in these mouse models produces a significant increase in evoked pain responses and an alteration in weight bearing. Since mice are quadrupeds, they offload the painful limb to the contralateral limb, to the forelimbs, or some combination. These methods are simple, require minimal equipment, and are reproducible and sensitive for detecting pain. They are useful for studying both disease-modifying arthritis treatments and analgesics in mice.

We have developed an evoked measure of arthritis pain and coupled it with a standardized method for measuring spontaneous pain in different murine models of chemically induced arthritis. These measures are sensitive and reproducible for different types of joint pain.

Pain is the main cause of disability from arthritis. There is currently an unmet need for adequate treatments for arthritis pain. Pre-clinical models are ...

The Lower Body Positive Pressure Treadmill for Knee Osteoarthritis Rehabilitation

Here, based on a clinician&rsquo;s point-of-view, we propose a two-model lower body positive pressure (LBPP) protocol (walking and squatting models) in addition to a clinical, functional assessment methodology, including details for further encouragement of the development of non-drug surgical intervention strategies in knee osteoarthritis patients. However, we only present the effect of LBPP training in improvement of pain and knee function in one patient through three-dimensional gait analysis. The exact, long-term effects of this approach should be explored in future studies.

Here, based on a clinician&#8217;s point-of-view, we propose a two-model lower body positive pressure (LBPP) protocol (walking and squatting models) in addition to a clinical, functional assessment methodology, including details for further encouragement of the development of non-drug surgical intervention strategies in knee osteoarthritis patients. However, we only present the effect of LBPP training in improvement of pain and knee function in one patient through three-dimensional gait analysis. The exact, long-term effects of this approach should be explored in future studies.

Here, based on a clinician&rsquo;s point-of-view, we propose a two-model lower body positive pressure (LBPP) protocol (walking and squatting models) in ...

Establishment of the KOA Model in Rabbits Using the Modified Videman Method

Application of Acupotomy in a Knee Osteoarthritis Model in Rabbit

Knee osteoarthritis (KOA) is one of the most frequently encountered diseases in the orthopedic department, which seriously reduces the quality of life of people with KOA. Among several pathogenic factors, the biomechanical imbalance of the knee joint is one of the main causes of KOA. Acupotomology believes that restoring the mechanical balance of the knee joint is the key to treating KOA. Clinical studies have shown that acupotomy can effectively reduce pain and improve knee mobility by reducing adhesion, contracture of soft tissues, and stress concentration points in muscles and tendons around the knee joint. 
In this protocol, we used the modified Videman method to establish a KOA model by immobilizing the left hindlimb in a straight position. We have outlined the method of operation and the precautions related to acupotomy in detail and evaluated the efficacy of acupotomy in conjunction with the theory of "Modulating Muscles and Tendons to Treat Bone Disorders" through the detection of the mechanical properties of quadriceps femoris and tendon, as well as cartilage mechanics and morphology. The results show that acupotomy has a protective effect on cartilage by adjusting the mechanical properties of the soft tissues around the knee joint, improving the cartilage stress environment, and delaying cartilage degeneration.

Author Spotlight: Investigating the Mechanism of Action of Acupotomy in Treating Knee Osteoarthritis

In this protocol, a knee osteoarthritis model was prepared using the modified Videman method, and the operation procedures and precautions of acupotomy are detailed. The effectiveness of acupotomy has been demonstrated by testing the mechanical properties of quadriceps femoris and tendon and the mechanical and morphological properties of cartilage.

Knee osteoarthritis (KOA) is one of the most frequently encountered diseases in the orthopedic department, which seriously reduces the quality of life of ...

Therapeutic Potential of Tuina Massage for Knee Osteoarthritis

Tuina Intervention in Sodium Monoiodoacetate Injection-Induced Rat Model of Knee Osteoarthritis

Knee osteoarthritis (KOA), a common degenerative joint disorder, is characterized by chronic pain and disability, which can progress to irreparable structural damage of the joint. Investigations into the link between articular cartilage, muscles, synovium, and other tissues surrounding the knee joint in KOA are of great importance. Currently, managing KOA includes lifestyle modifications, exercise, medication, and surgical interventions; however, the elucidation of the intricate mechanisms underlying KOA-related pain is still lacking. Consequently, KOA pain remains a key clinical challenge and a therapeutic priority. Tuina has been found to have a regulatory effect on the motor, immune, and endocrine systems, prompting the exploration of whether Tuina could alleviate KOA symptoms, caused by the upregulation of inflammatory factors, and further, if the inflammatory factors in skeletal muscle can augment the progression of KOA.
We randomized 32 male Sprague Dawley (SD) rats (180-220 g) into four groups of eight animals each: antiPD-L1+Tuina (group A), model (group B), Tuina (group C), and sham surgery (group D). For groups A, B, and C, we injected 25 &#181;L of sodium monoiodoacetate (MIA) solution (4 mg MIA diluted in 25 &#181;L of sterile saline solution) into the right knee joint cavity, and for group D, the same amount of sterile physiological saline was injected. All the groups were evaluated using the least to most stressful tests (paw mechanical withdrawal threshold, paw withdrawal thermal latency, swelling of the right knee joint, Lequesne MG score, skin temperature) before injection and 2, 9, and 16 days after injection.

Author Spotlight: Treating Knee Osteoarthritis with Tuina - A New Perspective 

This protocol describes the methods of Tuina intervention in sodium monoiodoacetate injection-induced rat model of knee osteoarthritis (KOA), which provides a reference for the application of Tuina in KOA animal models. This protocol also studies the effective mechanism of Tuina for KOA, and the results will help promote its application.

Knee osteoarthritis (KOA), a common degenerative joint disorder, is characterized by chronic pain and disability, which can progress to irreparable ...