Name: a mouse model of fatigue induced by peripheral irradiation
Uploaded: 2017-03-17T14:00:00.000+00:00
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Description: Watch this Scientific Journal Video about A Mouse Model of Fatigue Induced by Peripheral Irradiation at JoVE.com

The authors would like to thank Michele Allen of the National Heart, Lung, and Blood Institute (NHLBI) of the National Institutes of Health (NIH) for generously sharing her expertise in murine phenotyping methods and for her ongoing technical assistance, as well as for Timothy Hunt of NHLBI for helping us develop the shielding device. This study is supported by the Division of Intramural Research of the National Institute of Nursing Research of the NIH, and part of the validation trial is supported by a grant from the Oncology Nursing Society Foundation.

Ethics Statement: This study was approved by the National Institutes of Health (NIH) Animal Care and Use Committee. All investigators taking part in animal handling and measurement of study outcomes were properly trained by the NIH Office of Animal Care and Use and the National Heart, Lung, and Blood Institute Murine Phenotyping Core. All aspects of animal testing, housing, and environmental conditions used in this study were in compliance with The Guide for the Care and Use of Laboratory Animals11.
1. Housing and Experimental Animals
NOTE: House male C57BL/6 mice (roughly five weeks old upon arrival) individually throughout the experiment and provide ad libitum access to food and water. All cages are kept on a 12:12 h light-dark cycle with the light phase beginning at 6 am and dark phase at 6 pm.
<ol>
	<li>Identify the mice and assign them to individual standard ventilated mouse cages. Allow 24 h after the identification procedure for recovery. 
	NOTE: Tail tattoo is recommended as a means of identification to eliminate the possibility that an ear tag could get caught in a running wheel. Tattoo a number on the tail of each mouse, with the number on the tail matching the number written on the mouse&#39;s cage.</li>
	<li>Allow mice to acclimate to their cages for at least three more days, handling each mouse gently for a period of three minutes per day.</li>
</ol>
2. Running Wheel Acclimation and Baseline
<ol>
	<li>Introduce the mice to individual VWRA cages, each equipped with a running wheel connected to an electronic counter for continuous recording. 
	NOTE: All wheel counters connect to a computer through a single USB interface (see Materials List). The computer software calculates the number of wheel rotations, distance traveled, and average speed across each designated time interval of the specified total duration. Once the recording stops, the data are automatically saved both as text and as spreadsheets.</li>
	<li>Initiate recording of VWRA through the computer software interface. Set recording intervals to one hour and the duration to at least five days. Continue recording VWRA for at least five days. 
	NOTE: At the end of step 2.2, all mice should achieve a relatively consistent amount of daily wheel running activity. If not, then identify and exclude any outliers.</li>
	<li>Stop VWRA recording through the software interface, and return the mice to their standard cages described in step 1.1 (cages without running wheels).</li>
	<li>Randomize mice into either sham-irradiated control or irradiated groups.</li>
</ol>
3. Irradiation
Note: Perform the following steps for all mice in both groups, once per day for three sequential days. Treat mice in the same order each day.
<ol>
	<li>Anesthetize each mouse by intraperitoneal injection of a ketamine (100 mg/kg) and xylazine (10 mg/kg) mixture.</li>
	<li>Confirm anesthesia with a toe pinch and use ointment on the eyes to prevent dryness while under anesthesia.</li>
	<li>Transfer the anesthetized mouse into a lead shielding device. Arrange the mouse in the shielding so that only the lower abdominal/pelvic region is exposed. 
	NOTE: The shielding is composed of two lead &#34;boxes,&#34; with a narrow open space in between that allows radiation exposure to a small, targeted region of the mouse (see Figure 1).</li>
	<li>Use medical tape to secure the base of the mouse&#39;s tail in position within the shielding. 
	NOTE: Step 3.4 is optional, but doing so can help ensure that the position of the mouse does not change during the following step.</li>
	<li>Transport the shielding device into the irradiator, ensuring that the animal position within the shielding is maintained.</li>
	<li>If the mouse is in the irradiation group, deliver 800 cGy at a dose rate of about 110 cGy/min. If the mouse is in the sham-irradiation control group, leave the mouse in the inactive irradiator for the equivalent time. 
	NOTE: Optimal irradiator settings will depend on the particular device. The dose rate of 110 cGy/min delivered from a 137Cesium source is the central dose rate of the irradiator used here. The exposure time was adjusted to reach the desired total dose of 800 cGy.</li>
	<li>Remove the mouse from the irradiator and shielding, and then return it to its original, standard cage mentioned in step 1.1.</li>
	<li>Continuously monitor the mouse until it has regained sufficient consciousness to maintain sternal recumbency.</li>
</ol>
4. Radiation-induced Fatigue Measurement
<ol>
	<li>On the day after completion of three successive days of irradiation, transfer the mice to their individual VWRA cages described in step 2.1.</li>
	<li>Record VWRA, as described in step 2.2, except here setting the recording duration to more than 15 days. At the end of the 15 days, manually stop VWRA recording through the software interface. 
	NOTE: The data from each recording period are automatically saved as spreadsheets, each of which includes the rotation, distance, and speed measurements for all animals (columns) and at all intervals (rows) throughout the duration of recording. At the end of the experiment, there are two spreadsheets generated by the recording software: one for the pre-irradiation VWRA, and one for the post-irradiation VWRA.</li>
</ol>

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This research was supported by the Division of Intramural Research, National Institute of Nursing Research, National Institutes of Health.

We have described a protocol using targeted peripheral irradiation to induce a reduction of VWRA in mice without confounding morbidity or mortality. Importantly, a simple shielding device allows irradiation in this protocol to target a desired region consistently, mimicking the radiation treatments received by patients with pelvic cancer. In contrast to existing CRF models involving brain or total body irradiation8,9, this model explores how a peripherally-target...

Cancer-related fatigue (CRF) is a distressing and costly condition that often affects patients receiving cancer treatments1. The fatigue is neither proportional to recent activity nor alleviated by rest, and it is associated with a wide variety of disturbances related to mood, motivation, attention, and cognition2. The biological causes of CRF are unknown, though it has been shown in many cases to correlate with inflammation and cytokine levels, also in some cases with hemoglobin levels and the function of various hormone systems (see Saligan et al.3 for a review of biological studies of CRF).
Controlled studies using animal models are necessary to understand the behavior and biology associated with this complex condition. While tumor-related4 or chemotherapy-related5,6 fatigue has been studied in rodent models, the etiology of CRF may be treatment-specific. To investigate CRF related to radiation therapy, our group has recently developed a mouse model of irradiation-induced fatigue7. In contrast to existing CRF models involving brain or total body irradiation8,9, this model explores how a change in centrally-driven behavior, like fatigue, can be triggered by a peripherally-targeted irradiation procedure.
The procedure described here is designed to model radiation therapy administered to patients with pelvic cancer, using lead shielding to target the lower abdominal/pelvic region with irradiation. However, by modifying the lead shielding or its placement relative to experimental animals, this procedure could be adapted to model irradiation of other parts of the body. Voluntary wheel-running activity (VWRA) is used to measure fatigue-like behavior; because it&#39;s a voluntary and normal behavior10, it should allow the concurrent use of other behavioral and biological tests. We have found that peripheral irradiation is sufficient to reduce VWRA in mice without causing overt morbidity7. Future experiments with this model may help reveal effects of peripheral irradiation on immune and other biological signaling, as well as the downstream changes in the central nervous system that can produce deficits associated with CRF.

<table><tbody><tr><td>C57BL/6 Mice</td><td>Charles River</td><td></td><td>Strain code 027 (http://www.criver.com/products-services/basic-research/find-a-model/c57bl-6n-mouse)</td></tr><tr><td>Ketamine HCl</td><td>Putney</td><td></td><td>100 mg/mL stock solution</td></tr><tr><td>Xylazine HCl</td><td>Lloyd Laboratories</td><td></td><td>100 mg/mL stock solution</td></tr><tr><td>Rodent Tattoo System</td><td>AIMS</td><td>ATS-3</td><td>http://animalid.com/lab-animal-identification-systems/ats-3-general-rodent-tattoo-system</td></tr><tr><td>Lead Shielding Apparatus</td><td>(custom made)</td><td></td><td>One-inch thick lead shielding arranged as two boxes with a one-inch thick gap between them for targeted irradiation</td></tr><tr><td>Plexiglass shielding container</td><td>(custom made)</td><td></td><td>Plexiglass container filled with styrofoam. Styrofoam cutouts hold the lead shielding in place.</td></tr><tr><td>GammaCell 40 Exactor</td><td>Best Theratronics</td><td></td><td>http://www.theratronics.ca/product_gamma40.html</td></tr><tr><td>RAD Disk Ultra</td><td>Best Theratronics</td><td></td><td>http://www.theratronics.ca/product_rad.html</td></tr><tr><td>Mouse Single Activity Wheel Chamber</td><td>Lafayette Instrument Company</td><td>#80820</td><td>http://www.lafayetteneuroscience.com/product_detail.asp?itemid=980</td></tr><tr><td>Activity Wheel Counter for Computer Monitoring</td><td>Lafayette Instrument Company</td><td>#86061</td><td>http://www.lafayetteneuroscience.com/product_detail.asp?itemid=1052</td></tr><tr><td>Modular Cable for Wheel Counters</td><td>Lafayette Instrument Company</td><td>#86051-7</td><td>http://www.lafayetteneuroscience.com/product_detail.asp?itemid=1046</td></tr><tr><td>USB Computer Interface for Activity Wheel Counters</td><td>Lafayette Instrument Company</td><td>#86056A</td><td>http://www.lafayetteneuroscience.com/product_detail.asp?itemid=1047</td></tr><tr><td>Activity Wheel Monitor Software</td><td>Lafayette Instrument Company</td><td>#86065</td><td>http://www.lafayetteneuroscience.com/product_detail.asp?itemid=1053</td></tr></tbody></table>

a mouse model of fatigue induced by peripheral irradiation

Cancer-related fatigue (CRF) is a distressing and costly condition that often affects patients receiving cancer treatments, including radiation therapy. Here we describe a method using targeted peripheral irradiation to induce fatigue-like behavior in mice. With appropriate shielding, the irradiation targets the lower abdominal/pelvic region of the mouse, sparing the brain, in an effort to model radiation treatment received by individuals with pelvic cancers. We deliver an irradiation dose that is sufficient to induce fatigue-like behavior in mice, measured by voluntary wheel-running activity (VWRA), without causing obvious morbidity. Since wheel running is a normal, voluntary behavior in mice, its use should have little confounding effect on other behavioral tests or biological measures. Hence, wheel running can be used as a feasible outcome measure in understanding the behavioral and biological correlates of fatigue. CRF is a complex condition with frequent comorbidities, and likely has causes related both to cancer and its various treatments. The methods described in this paper are useful for investigating radiation-induced changes that contribute to the development of CRF and, more generally, to explore the biological networks that can explain the development and persistence of a peripherally-triggered but centrally-driven behavior like fatigue.

Three batches of mice were run through the protocol described above. There were a total of 16 sham and 20 irradiated (2,400 cGy, 3 x 800 cGy/day) mice. After three consecutive days of irradiation, the irradiated group showed significantly reduced VWRA compared to sham (mixed repeated measures ANOVA: main effect of irradiation treatment, F1,13 = 19.233, p &#60; 0.001). The effect was significant for the first seven days after irradiation (simple main effects, p &#60; 0.05 with B...

Watch this Scientific Journal Video about A Mouse Model of Fatigue Induced by Peripheral Irradiation at JoVE.com

A Mouse Model of Fatigue Induced by Peripheral Irradiation

We describe a method using targeted peripheral irradiation to induce fatigue-like behavior in mice. The selected non-lethal irradiation dose leads to a week-long reduction in voluntary wheel-running activity.

Cancer-related fatigue (CRF) is a distressing and costly condition that often affects patients receiving cancer treatments, including radiation therapy. ...

a-mouse-model-of-fatigue-induced-by-peripheral-irradiation

Universidad de Cartagena UDEC

Research

JoVE Journal

Cancer Research

7.8K Views.  National Institutes of Health. We describe a method using targeted peripheral irradiation to induce fatigue-like behavior in mice. The selected non-lethal irradiation dose leads to a week-long reduction in voluntary wheel-running activity.

Video: A Mouse Model of Fatigue Induced by Peripheral Irradiation

Fluorescent Orthotopic Mouse Model of Pancreatic Cancer

Pancreatic cancer remains one of the cancers for which survival has not improved substantially in the last few decades. Only 7% of diagnosed patients will survive longer than five years. In order to understand and mimic the microenvironment of pancreatic tumors, we utilized a murine orthotopic model of pancreatic cancer that allows non-invasive imaging of tumor progression in real time. Pancreatic cancer cells expressing green fluorescent protein (PANC-1 GFP) were suspended in basement membrane matrix, high concentration, (e.g., Matrigel HC) with serum-free media and then injected into the tail of the pancreas via laparotomy. The cell suspension in the high concentration basement membrane matrix becomes a gel-like substance once it reaches room temperature; therefore, it gels when it comes in contact with the pancreas, creating a seal at the injection site and preventing any cell leakage. Tumor growth and metastasis to other organs are monitored in live animals by using fluorescence. It is critical to use the appropriate filters for excitation and emission of GFP. The steps for the orthotopic implantation are detailed in this article so researchers can easily replicate the procedure in nude mice. The main steps of this protocol are preparation of the cell suspension, surgical implantation, and whole body fluorescent in vivo imaging. This orthotopic model is designed to investigate the efficacy of novel therapeutics on primary and metastatic tumors.

A procedure to implant green fluorescent protein-expressing pancreatic cancer cells (PANC-1 GFP) orthotopically into the pancreas of Balb-c Ola Hsd-Fox1nu mice to assess tumor progression and metastasis is presented here.

Pancreatic cancer remains one of the cancers for which survival has not improved substantially in the last few decades. Only 7% of diagnosed patients will ...

Evaluating the Role of Mitochondrial Function in Cancer-related Fatigue

Fatigue is a common and debilitating condition that affects most cancer patients. To date, fatigue remains poorly characterized with no diagnostic test to objectively measure the severity of this condition. Here we describe an optimized method for assessing mitochondrial function of PBMCs collected from fatigued cancer patients. Using a compact extracellular flux system and sequential injection of respiratory inhibitors, we examined PBMC mitochondrial functional status by measuring basal mitochondrial respiration, spare respiratory capacity, and energy phenotype, which describes the preferred energy pathway to respond to stress. Fresh PBMCs are readily available in the clinical setting using standard phlebotomy. The entire assay described in this protocol can be completed in less than 4 hours without the involvement of complex biochemical techniques. Additionally, we describe a normalization method that is necessary for obtaining reproducible data. The simple procedure and normalization methods presented allow for repeated sample collection from the same patient and generation of reproducible data that can be compared between time points to evaluate potential treatment effects.

Our goal was to develop a practical protocol to evaluate mitochondrial dysfunction associated with fatigue in cancer patients. This innovative protocol is optimized for clinical use involving only standard phlebotomy and basic laboratory procedures.

Fatigue is a common and debilitating condition that affects most cancer patients. To date, fatigue remains poorly characterized with no diagnostic test to ...

The Treadmill Fatigue Test: A Simple, High-throughput Assay of Fatigue-like Behavior for the Mouse

Fatigue is a prominent symptom in many diseases and disorders and reduces quality of life for many people. The lack of clear pathogenesis and failure of current interventions to adequately treat fatigue in all patients leaves a need for new treatment options. Despite the therapeutic need and importance of preclinical research in helping identify promising novel treatments, few preclinical assays of fatigue are available. Moreover, the most common preclinical assay used to assess fatigue-like behavior, voluntary wheel running, is not suitable for use with some strains of mice, may not be sensitive to drugs that reduce fatigue, and has relatively low throughput. The current protocol describes a novel, non-voluntary preclinical assay of fatigue-like behavior, the treadmill fatigue test, and provides evidence of its efficacy in detecting fatigue-like behavior in mice treated with a chemotherapy drug known to cause fatigue in humans and fatigue-like behavior in animals. This assay may be a beneficial alternative to wheel running, as fatigue-like behavior and potential interventions can be assessed in a greater number of mice over a shorter time frame, thus permitting faster discovery of new therapeutic options.

Fatigue is a common, undertreated and frequently poorly-understood symptom in many diseases and disorders. New preclinical assays of fatigue may help to improve current understanding and future treatment of fatigue. To that end, the current protocol provides a novel means of measuring fatigue-like behavior in the mouse.

Fatigue is a prominent symptom in many diseases and disorders and reduces quality of life for many people. The lack of clear pathogenesis and failure of ...

Behavior

Functional Interrogation of Adult Hypothalamic Neurogenesis with Focal Radiological Inhibition

The functional characterization of adult-born neurons remains a significant challenge. Approaches to inhibit adult neurogenesis via invasive viral delivery or transgenic animals have potential confounds that make interpretation of results from these studies difficult. New radiological tools are emerging, however, that allow one to noninvasively investigate the function of select groups of adult-born neurons through accurate and precise anatomical targeting in small animals. Focal ionizing radiation inhibits the birth and differentiation of new neurons, and allows targeting of specific neural progenitor regions. In order to illuminate the potential functional role that adult hypothalamic neurogenesis plays in the regulation of physiological processes, we developed a noninvasive focal irradiation technique to selectively inhibit the birth of adult-born neurons in the hypothalamic median eminence. We describe a method for Computer tomography-guided focal irradiation (CFIR) delivery to enable precise and accurate anatomical targeting in small animals. CFIR uses three-dimensional volumetric image guidance for localization and targeting of the radiation dose, minimizes radiation exposure to nontargeted brain regions, and allows for conformal dose distribution with sharp beam boundaries. This protocol allows one to ask questions regarding the function of adult-born neurons, but also opens areas to questions in areas of radiobiology, tumor biology, and immunology. These radiological tools will facilitate the translation of discoveries at the bench to the bedside.

The function of adult-born mammalian neurons remains an active area of investigation. Ionizing radiation inhibits the birth of new neurons. Using computer tomography-guided focal irradiation (CFIR), three-dimensional anatomical targeting of specific neural progenitor populations can now be used to assess the functional role of adult neurogenesis.

The functional characterization of adult-born neurons remains a significant challenge. Approaches to inhibit adult neurogenesis via invasive viral ...

Neuroscience

Establishment of a Robust and Reproducible Model of Radiation-Induced Skin and Muscle Fibrosis

Radiation-induced skin fibrosis (RISF) can result from a plethora of scenarios including cancer therapy, accidental exposure, or acts of terrorism. Radioactive beams can penetrate through the skin and affect the structures in their path including skin, muscles, and internal organs. Skin is the first structure to get exposed to radiation and is susceptible to develop chronic fibrosis, which is challenging to treat. Currently, limited treatment options show moderate efficacy in mitigating radiation-related skin fibrosis. A key factor hindering the development of effective countermeasures is the absence of a convenient and robust model that could allow for translation of the experimental findings to humans. Here, a robust and reproducible murine hind limb skin fibrosis model has been established for prophylactic and therapeutic evaluation of possible agents for functional and molecular recovery.
The right hind limb was irradiated using a single dose of 40 (Gray) Gy to induce skin fibrosis. Subjects developed edema and dermatitis in the early stages proceeded by visible skin constriction. Irradiated limbs showed a significantly reduced limb range of motion in the following weeks. In late stages, acute side effects subsided, yet chronic fibrosis persisted. A gait index was performed as an additional functional assay, which demonstrated the development of functional impairment. These non-invasive methods demonstrated reliable measurements for tracing fibrosis progression, which is supported by histological analyses. The radiation dose, application, and post-irradiation analyses employed in this model offer a vigorous and reproducible method for studying radiation-induced skin fibrosis and testing the efficacy of therapeutical agents.

Here we present a protocol to induce radiation-induced skin fibrosis in the hind limb of mice and perform post-irradiation measurements of chronic impairment via limb excursion and gait index analyses to evaluate the functional outcome. The model elucidates radiation-related skin fibrosis mechanisms and is useful in subclinical therapeutic studies.

Radiation-induced skin fibrosis (RISF) can result from a plethora of scenarios including cancer therapy, accidental exposure, or acts of terrorism. ...

Diffuse Optical Spectroscopy for the Quantitative Assessment of Acute Ionizing Radiation Induced Skin Toxicity Using a Mouse Model

Acute skin toxicities from ionizing radiation (IR) are a common side effect from therapeutic courses of external beam radiation therapy (RT) and negatively impact patient quality of life and long term survival. Advances in the understanding of the biological pathways associated with normal tissue toxicities have allowed for the development of interventional drugs, however, current response studies are limited by a lack of quantitative metrics for assessing the severity of skin reactions. Here we present a diffuse optical spectroscopic (DOS) approach that provides quantitative optical biomarkers of skin response to radiation. We describe the instrumentation design of the DOS system as well as the inversion algorithm for extracting the optical parameters. Finally, to demonstrate clinical utility, we present representative data from a pre-clinical mouse model of radiation induced erythema and compare the results with a commonly employed visual scoring. The described DOS method offers an objective, high through-put evaluation of skin toxicity via functional response that is translatable to the clinical setting.

We present a diffuse optical spectroscopic (DOS) approach that provides quantitative optical biomarkers of skin response to radiation. We describe DOS instrumentation design, optical parameters extraction algorithms and the animal handling procedures required to yield representative data from a pre-clinical mouse model of radiation induced erythema.

Acute skin toxicities from ionizing radiation (IR) are a common side effect from therapeutic courses of external beam radiation therapy (RT) and ...

Medicine

A Rat Model of Central Fatigue Using a Modified Multiple Platform Method

In this article, we introduced a rat model of central fatigue using the modified multiple platform method (MMPM). The Multiple Platform box was designed as a water tank with narrow platforms on the bottom. The model rats were put into the tank and stood on the platforms for 14 h (18:00 - 8:00) per day for a consecutive 21 days, with a blank control group set for contrast. At the end of modeling, rats in the model group showed an obvious fatigued appearance. To assess the model, we performed several behavioral tests, including the open field test (OFT), the elevated plus maze (EPM) test, and the exhaustive swimming (ES) test. The results showed that anxiety, spatial cognition impairment, poor muscle performance, and declined voluntary activity presented in model rats confirm the diagnosis of&#160;central fatigue. Changes of the central neurotransmitters also verified the result. In conclusion, the model successfully simulated central fatigue, and future study with the model may help reveal the pathological mechanism of the disease.

Here, we present a protocol to introduce a rat model of central fatigue using the modified multiple platform method (MMPM).

In this article, we introduced a rat model of central fatigue using the modified multiple platform method (MMPM). The Multiple Platform box was designed ...

A Preclinical Model of Exertional Heat Stroke in Mice

Heat stroke is the most severe manifestation of heat-related illnesses. Classic heat stroke (CHS), also known as passive heat stroke, occurs at rest, whereas exertional heat stroke (EHS) occurs during physical activity. EHS differs from CHS in etiology, clinical presentation, and sequelae of multi-organ dysfunction. Until recently, only models of CHS have been well established. This protocol aims to provide guidelines for a refined preclinical mouse model of EHS that is free from major limiting factors such as the use of anesthesia, restraint, rectal probes, or electric shock. Male and female C57Bl/6 mice, instrumented with core temperature (Tc) telemetric probes were utilized in this model. For familiarization with the running mode, mice undergo 3 weeks of training using both voluntary and forced running wheels. Thereafter, mice run on a forced wheel inside a climatic chamber set at 37.5 &#176;C and 40%-50% relative humidity (RH) until displaying symptom limitation (e.g., loss of consciousness) at Tc of 42.1-42.5 &#176;C, although suitable results can be obtained at chamber temperatures between 34.5-39.5 &#176;C and humidity between 30%-90%. Depending on the desired severity, mice are removed from the chamber immediately for recovery in ambient temperature or remain in the heated chamber for a longer duration, inducing a more severe exposure and a higher incidence of mortality. Results are compared with sham-matched exercise controls (EXC) and/or na&#239;ve controls (NC). The model mirrors many of the pathophysiological outcomes observed in human EHS, including loss of consciousness, severe hyperthermia, multi-organ damage as well as inflammatory cytokine release, and acute phase responses of the immune system. This model is ideal for hypothesis-driven research to test preventative and therapeutic strategies that may delay the onset of EHS or reduce the multi-organ damage that characterizes this manifestation.

The protocol describes the development of a standardized, repeatable, preclinical model of exertional heat stroke (EHS) in mice free from adverse external stimuli such as electric shock. The model provides a platform for mechanistic, preventative, and therapeutic studies.

Heat stroke is the most severe manifestation of heat-related illnesses. Classic heat stroke (CHS), also known as passive heat stroke, occurs at rest, ...

Shocktube Method to Model Highly Repetitive Low-Level Blast in Mice

Modeling Highly Repetitive Low-level Blast Exposure in Mice

Exposure to explosive blasts is a significant risk factor for brain trauma among exposed persons. Although the effects of large blasts on the brain are well understood, the effects of smaller blasts such as those that occur during military training are less understood. This small, low-level blast exposure also varies highly according to military occupation and training tempo, with some units experiencing few exposures over the course of several years whereas others experience hundreds within a few weeks. Animal models are an important tool in identifying both the injury mechanisms and long-term clinical health risks following low-level blast exposure. Models capable of recapitulating this wide range of exposures are necessary to inform acute and chronic injury outcomes across these disparate risk profiles.
Although outcomes following a few low-level blast exposures are easily modeled for mechanistic study, chronic exposures that occur over a career may be better modeled by blast injury paradigms with repeated exposures that occur frequently over weeks and months. Shown here are methods for modeling highly repetitive low-level blast exposure in mice. The procedures are based on established and widely used pneumatic shocktube models of open-field blast exposure that can be scaled to adjust the overpressure parameters and the number or interval of the exposures. These methods can then be used to either enable mechanistic investigations or recapitulate the routine blast exposures of clinical groups under study.

Author Spotlight: Deciphering the Long-Term Effects of Low-Level Blast Exposures in Mice

Presented here are methods for producing repeated low-intensity blast exposures using mice.

Exposure to explosive blasts is a significant risk factor for brain trauma among exposed persons. Although the effects of large blasts on the brain are ...

Assessing the Impact of Anti-Fatigue Decoction on Rat Central Fatigue

The Effect of Anti-Fatigue Decoction on the Behaviors and Serological Indicators in a Central Fatigue Rat Model

This study aimed to assess the effects of Anti-fatigue Decoction (AFD) against central fatigue by observing the behaviors and serological indicators of rats modeled by the modified multiple platform method (MMPM) after drug intervention. Grip strength measurements were used to evaluate the muscle strength of rats. The open field test was utilized to assess anxiety-like behavior, while the Morris water maze test was conducted to evaluate the memory function of the rats. Following the behavioral assessments, rat serum samples were collected to measure the concentrations of corticosterone (CORT) and lactic acid (LAC). The concentration of LAC was determined using the colorimetric method, while the concentration of CORT was measured using the enzyme-linked immunosorbent assay (ELISA) method. Compared to the blank control group, following MMPM modeling, rats exhibited significant reductions in grip strength and impaired ability to memory. The serum analysis revealed increased levels of LAC and CORT in the model group rats. AFD can noticeably reverse these adverse changes to a certain extent. These findings highlight the positive effects of AFD and coenzymeQ10 on physical and cognitive abilities and alterations in serum biomarker levels of central fatigue rats.

Here, we introduce a protocol to assess the effects of anti-fatigue decoction (AFD) on central fatigue in rats modeled by the modified multiple platform method (MMPM) by monitoring both their behavioral responses and serological markers.

This study aimed to assess the effects of Anti-fatigue Decoction (AFD) against central fatigue by observing the behaviors and serological indicators of ...