这项工作得到了瑞士达沃斯 RISystem 股份公司的支持。

所有的程序都是根据国家卫生研究院关于使用实验动物的指导方针进行的, 并遵循机构指南 (Landesamt Verbraucherschutz、Zentralstelle Amtstierärztlicher Dienst、萨尔布吕肯、德国)。
1. 外科器械和植入物的制备
<ol><li>选择手术刀刀片 (大小 15), 小拭子, 细钳, 27 克针, 非可吸收5-0 缝合, 剪刀和针持有人从显微外科仪器盒。</li>
	<li>解锁髓内螺钉、导丝 (直径 0.3/0.2 毫米、10厘米长)、定心钻头 (0.5 毫米直径) 和手钻 (图 1; 请参阅材料表)。 注: 髓内螺钉 (0.5 毫米直径, 17.2 毫米长度) 是由医疗级不锈钢制成, 用于逆行植入股骨。该螺钉有一个近端螺纹 (直径0.5 毫米, 4 毫米长度) 与鼻子 (0.2 毫米直径, 0.4 毫米长度) 在尖端和远端锥形头 (0.8 毫米直径, 0.9 毫米长度), 以实现骨折压缩以及轴向和旋转稳定性。</li>
	<li>将植入物和所有手术器械暴露在消毒液中 (96% 酒精) 5 分钟或消毒 (蒸汽灭菌, 130 摄氏度, 25 分钟)。消毒或灭菌后, 将仪器放置在操作布上。将操作布直接放置在小动物操作桌旁。</li>
</ol>2. 动物、麻醉和镇痛
<ol><li>根据所讨论的研究问题, 选择小鼠的应变、年龄和性别。 注: 本研究使用 12-至14周的雄性 CD-1 小鼠。适当的体重使用髓内螺钉是在25-35 克之间。</li>
	<li>麻醉小鼠腹腔注射15毫克/千克甲苯噻嗪和75毫克/千克氯胺酮。通过脚趾夹来确认麻醉。使用眼部润滑剂, 以保护动物的眼睛在麻醉期间的干燥。麻醉后, 将鼠标置于散热器下, 保持体温恒定。在手术过程中, 动物受到反复脚趾捏的监测, 以确保适当的麻醉面。</li>
	<li>应用盐酸曲马多在饮用水 (1.0 毫克/毫升) 镇痛从1天之前的手术, 直到3天手术后。 注: 镇痛和感染预防应符合国家和机构在进行实验的相关指导方针。</li>
</ol>3. 外科手术和髓内螺钉植入术
<ol><li>手术前, 剃掉整条右后腿, 涂上脱毛膏。5分钟后, 取出奶油, 用清水清洁腿部。然后, 使用96% 酒精消毒液。Betadine 或洗必泰可以添加到酒精, 以确保完全无菌。</li>
	<li>在无菌条件下, 将鼠标放在小动物操作台上的仰卧位上。弯曲右膝, 允许前路髁膝。使用手术刀刀片在右膝上执行5毫米内侧 parapatellar 切口。</li>
	<li>用手术刀刀片和拭子仔细地调动髌骨韧带。然后, 用细钳将髌骨侧面移位, 以暴露股骨髁间凹槽。</li>
	<li>在两个髁之间, 在股骨中部完全打开髁间凹槽。请确保钻孔的深度不要超过1.0 毫米。<ol>
<li>使用 0.5 mm 定心钻头和手钻 (图 1C和D,图 2), 以慢速和45°偏移腹部到股骨轴进行手动钻孔。在钻探过程中, 持续减少角度到0°偏移 (平行与骨轴的股骨)。当达到1.0 毫米深度时, 停止钻孔。</li>
	</ol>
</li>
	<li>在髁间凹槽处打开骨后, 将27克针插入髓内腔, 使其在股骨的全长。通过27克针的旋转运动, 手动将股骨髓内腔固定。向前推针, 以穿孔的皮质骨在大转子下部。</li>
	<li>取出27克针, 并将导丝通过股骨远端。<ol>
<li>用手术刀刀片 (尺寸 15) 在导丝上进行皮肤切口, 并将导丝向前推, 直到导丝两端都在外面。请务必把导丝放到位。</li>
	</ol>
</li>
	<li>使用断头台创建定义闭合的断裂。<ol>
<li>将鼠标放在断头台下的右腿位置。确保股骨的骨干部分放在断头台的中间。</li>
		<li>将重量 (200 克) 从所定义的25.5 厘米的距离中除去。</li>
	</ol>
</li>
	<li>使用 x 射线设备控制断开的配置和断开位置以及导丝 (图 3) 的位置 (请参阅材料表)。</li>
	<li>将髓内螺钉与远端的鼻部连接至0.2 毫米导丝, 并在连续压力下将其插入股骨, 并顺时针旋转。<ol>
<li>当达到足够扭矩时, 驱动轴的剪切。</li>
		<li>卸下导丝下部。</li>
	</ol>
</li>
	<li>用5-0 合成、单丝、美容整形聚丙烯缝合术, 将髌骨重新定位, 用一条缝合固定髌骨肌腱。使用相同的材料和大小的单一缝合闭合伤口。使用 x 射线设备控制碎片和螺钉位置放射学上的减少 (请参阅材料表)。</li>
	<li>把动物放在散热器下, 直到他们从麻醉中恢复。不要离开动物无人看管, 直到他们恢复足够的意识, 以保持腹卧床。把动物送到动物设施的单人笼子里。在头24小时内, 不要将动物送回其他动物的公司, 即使他们已经完全从麻醉中恢复过来。</li>
	<li>每天仔细监视动物。在头三天内用1.0 毫克/毫升的饮用水维持术后镇痛。继续镇痛如果, 在手术后的4天, 动物仍然显示疼痛的证据, 如发声, 躁动, 缺乏机动性, 没有新郎, 异常的姿势, 和缺乏正常的环境兴趣。当动物无痛时, 终止镇痛。</li>
	<li>实验结束时, 弄死的巴比妥过量。</li>
</ol>

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作者声明他们没有竞争的财政利益。

手术步骤的关键步骤是找到正确的入口点的螺钉植入在股骨中部髁在髁间凹槽, 以及最佳方向平行的针骨轴为扩孔髓内腔。为了避免输入位置不正确, 外科医生应该准备好切口, 直到达到最佳的视野。为了控制扩孔过程中的定位, 应将小鼠的股骨固定在手指的稳定位置。另一个关键步骤是将螺钉插入到股骨上方的导丝上, 因为导丝可以从近端骨碎片中滑出, 导致骨折脱位。在这种情况下, 外科医生可?...

由于广泛的抗体和基因改良的动物, 小鼠的骨愈合研究是非常需要的。这些事实允许研究骨骼愈合的分子机制1。在过去的几年中, 不同的骨骼愈合模型的小鼠已经开发了2。这些模型可以分为开放模型, 其中骨骼是 osteotomized 使用开放的外侧手术方法和封闭模型, 其中骨是骨折的基础上, 由 Bonnares 和埃霍恩介绍的断裂模型3。使用这种技术, 一个标准化的横向骨折可以由一个3点弯曲装置和髓内植入物可以插入通过一个小的内侧 parapatellar 切口的微创技术, 以避免重大软组织创伤。
髓内螺钉可用于小鼠闭合性骨折的稳定。螺杆提供旋转和轴向稳定性。这是通过断开压缩通过近端线程和远端头4实现的。螺钉的进一步优点是手术技术简单, invasivity 低, 种植体重量低, 最显著的是, 与其他髓内固定相比, 提供标准化和可控制的生物力学条件的稳定性更高。植入5。事实上, 在最闭合的断裂模型中, 碎片只通过简单的针脚稳定, 这与完全缺乏旋转和轴向稳定性以及高的针脚风险和断裂脱位有关。这会明显影响愈合过程, 这可能导致延迟愈合或非联合形成。
众所周知, 骨折固定的稳定性对愈合过程有巨大影响6,7。高刚性固定的结果膜内愈合, 而不刚性固定, 这可能允许 micromovements 在骨折间隙, 导致软骨愈合。骨折与髓内螺钉的稳定主要表现为软骨愈合与大量的愈伤组织, 特别是经过2周的骨折愈合。收获大量愈伤组织的可能性可以通过不同的技术分析多种参数。
本文报道了小鼠髓内螺钉的设计和应用, 以及在正常软骨骨愈合实验研究中的优缺点。

<table><tbody><tr><td>Mouse Screw</td><td>RISystem AG</td><td>221,100</td><td></td></tr><tr><td>Guide wire</td><td>RISystem AG</td><td>521,100</td><td></td></tr><tr><td>Centering bit</td><td>RISystem AG</td><td>590,205</td><td></td></tr><tr><td>Hand drill</td><td>RISystem AG</td><td>390,130</td><td></td></tr><tr><td>Cotton-Swab (150 mm, small head)</td><td>Fink Walter GmbH</td><td>8822428</td><td></td></tr><tr><td>Suture (5-0 Prolene)</td><td>Ethicon</td><td>8614H</td><td></td></tr><tr><td>Forceps</td><td>Braun Aesculap AG &amp;amp;CoKG</td><td>BD520R</td><td></td></tr><tr><td>Scissors</td><td>Braun Aesculap AG &amp;amp;CoKG</td><td>BC100R</td><td></td></tr><tr><td>Needle holder</td><td>Braun Aesculap AG &amp;amp;CoKG</td><td>BM024R</td><td></td></tr><tr><td>27 G needle</td><td>Braun Melsungen AG</td><td>9186182</td><td></td></tr><tr><td>Scalpel blade size 15</td><td>Braun Aesculap AG &amp;amp;CoKG</td><td>16600525</td><td></td></tr><tr><td>Heat radiator</td><td>Sanitas</td><td>605.25</td><td></td></tr><tr><td>Depilatory cream</td><td>Asid bonz GmbH</td><td>NDXZ10</td><td></td></tr><tr><td>Eye lubricant</td><td>Bayer Vital GmbH</td><td>2182442</td><td></td></tr><tr><td>Xylazine</td><td>Bayer Vital GmbH</td><td>1320422</td><td></td></tr><tr><td>Ketamine</td><td>Serumwerke Bernburg</td><td>7005294</td><td></td></tr><tr><td>Tramadol</td><td>Gr&amp;uuml;nenthal GmbH</td><td>2256241</td><td></td></tr><tr><td>Disinfection solution (SoftaseptN)</td><td>Braun Melsungen AG</td><td>8505018</td><td></td></tr><tr><td>CD-1 mice</td><td>Charles River</td><td>22</td><td></td></tr><tr><td>X-ray Device</td><td>Faxitron MX-20, Faxitron X-ray Corporation</td><td>2321A0988</td><td></td></tr><tr><td>Fracture device small</td><td>RISystem AG</td><td>891,100</td><td></td></tr></tbody></table>

a minimally invasive model to analyze endochondral fracture healing in mice under standardized biomechanical conditions

骨愈合模型是必要的分析骨折愈合的复杂机制, 以改善临床骨折治疗。在过去的十年中, 在骨科研究中增加了老鼠模型的使用, 这很可能是因为老鼠模型提供了大量的基因改良菌株和特殊的抗体来分析骨折愈合的分子机制。为了控制生物力学条件, 具有良好特征的内固定技术是强制性的, 也在小鼠。在这里, 我们报告的设计和使用闭合骨愈合模型, 以稳定股骨骨折的小鼠。采用医用不锈钢制成的髓内螺钉, 通过与主要使用的简单髓内针相比, 可提供轴向和旋转稳定性, 这表明完全缺乏轴向和旋转稳定性。用髓内螺钉实现的稳定性可以分析软骨愈合。大量的愈伤组织, 在与螺钉稳定后接受, 提供了理想的条件, 以收获组织的生物化学和分子分析。螺钉使用的另一个好处是, 螺钉可以用微创技术插入股骨, 而不会引起软组织损伤。总之, 螺钉是一种独特的植入物, 最好能用于闭合性骨折愈合模型, 提供标准化的生物力学条件。

从皮肤切口到伤口闭合的手术时间为20分钟。手术可以在没有立体显微镜的情况下进行。术后每天对动物进行监测。术后镇痛在2天后终止, 因为没有动物在这个时间段后显示疼痛的证据。在手术后2天内, 动物也显示正常的负重。在整个观察期内未观察到伤口感染。
2周后的放射性分析表明, 愈伤组织的形成, 弥合骨折间隙 (<strong ...

Watch this Scientific Journal Video about A Minimally Invasive Model to Analyze Endochondral Fracture Healing in Mice Under Standardized Biomechanical Conditions at JoVE.com

A Minimally Invasive Model to Analyze Endochondral Fracture Healing in Mice Under Standardized Biomechanical Conditions

本协议描述了一种微创内固定技术, 采用髓内螺钉规范化稳定股骨骨折, 可用于分析软骨骨愈合的小鼠。

标准化生物力学条件下小鼠软骨骨折愈合的微创模型分析

Bone healing models are necessary to analyze the complex mechanisms of fracture healing to improve clinical fracture treatment. During the last decade, an ...

a-minimally-invasive-model-to-analyze-endochondral-fracture-healing

Universidad de Cartagena UDEC

Research

JoVE Journal

Medicine

8.2K 次观看.  Saarland University. 本协议描述了一种微创内固定技术, 采用髓内螺钉规范化稳定股骨骨折, 可用于分析软骨骨愈合的小鼠。

视频: A Minimally Invasive Model to Analyze Endochondral Fracture Healing in Mice Under Standardized Biomechanical Conditions

A Simple Critical-sized Femoral Defect Model in Mice

While bone has a remarkable capacity for regeneration, serious bone trauma often results in damage that does not properly heal. In fact, one tenth of all limb bone fractures fail to heal completely due to the extent of the trauma, disease, or age of the patient. Our ability to improve bone regenerative strategies is critically dependent on the ability to mimic serious bone trauma in test animals, but the generation and stabilization of large bone lesions is technically challenging. In most cases, serious long bone trauma is mimicked experimentally by establishing a defect that will not naturally heal. This is achieved by complete removal of a bone segment that is larger than 1.5 times the diameter of the bone cross-section. The bone is then stabilized with a metal implant to maintain proper orientation of the fracture edges and allow for mobility. 
Due to their small size and the fragility of their long bones, establishment of such lesions in mice are beyond the capabilities of most research groups. As such, long bone defect models are confined to rats and larger animals. Nevertheless, mice afford significant research advantages in that they can be genetically modified and bred as immune-compromised strains that do not reject human cells and tissue.
Herein, we demonstrate a technique that facilitates the generation of a segmental defect in mouse femora using standard laboratory and veterinary equipment. With practice, fabrication of the fixation device and surgical implantation is feasible for the majority of trained veterinarians and animal research personnel. Using example data, we also provide methodologies for the quantitative analysis of bone healing for the model.

Animal models are frequently employed to mimic serious bone injury in biomedical research. Due to their small size, establishment of stabilized bone lesions in mice are beyond the capabilities of most research groups. Herein, we describe a simple method for establishing and analyzing experimental femoral defects in mice.

一个简单的临界尺寸股骨缺损模型小鼠

While bone has a remarkable capacity for regeneration, serious bone trauma often results in damage that does not properly heal. In fact, one tenth of all ...

科研

医学

Establishment of a Segmental Femoral Critical-size Defect Model in Mice Stabilized by Plate Osteosynthesis

The use of tissue-engineered bone constructs is an appealing strategy to overcome drawbacks of autografts for the treatment of massive bone defects. As a model organism, the mouse has already been widely used in bone-related research. Large diaphyseal bone defect models in mice, however, are sparse and often use bone fixation which fills the bone marrow cavity and does not provide optimal mechanical stability. The objectives of the current study were to develop a critical-size, segmental, femoral defect in nude mice. A 3.5-mm mid-diaphyseal femoral ostectomy (approximately 25% of the femur length) was performed using a dedicated jig, and was stabilized with an anterior located locking plate and 4 locking screws. The bone defect was subsequently either left empty or filled with a bone substitute (syngenic bone graft or coralline scaffold). Bone healing was monitored noninvasively using radiography and in vivo micro-computed-tomography and was subsequently assessed by ex vivo micro-computed-tomography and undecalcified histology after animal sacrifice, 10 weeks postoperatively. The recovery of all mice was excellent, a full-weight-bearing was observed within one day following the surgical procedure. Furthermore, stable bone fixation and consistent fixation of the implanted materials were achieved in all animals tested throughout the study. When the bone defects were left empty, non-union was consistently obtained. In contrast, when the bone defects were filled with syngenic bone grafts, bone union was always observed. When the bone defects were filled with coralline scaffolds, newly-formed bone was observed in the interface between bone resection edges and the scaffold, as well as within a short distance within the scaffold. 
The present model describes a reproducible critical-size femoral defect stabilized by plate osteosynthesis with low morbidity in mice. The new load-bearing segmental bone defect model could be useful for studying the underlying mechanisms in bone regeneration pertinent to orthopaedic applications.

Although mouse models are invaluable tools for bone tissue engineering, models of long bone defects are sparse. This need motivated development of the present protocol which uses a locking plate with four screws and a dedicated jig to perform and stabilize a reproducible, femoral, critical-size defect with low morbidity.

在小鼠节段性股临界尺寸缺陷模型的建立接骨板稳定

The use of tissue-engineered bone constructs is an appealing strategy to overcome drawbacks of autografts for the treatment of massive bone defects. As a ...

Real-time Visualization and Analysis of Chondrocyte Injury Due to Mechanical Loading in Fully Intact Murine Cartilage Explants

Homeostasis of articular cartilage depends on the viability of resident cells (chondrocytes). Unfortunately, mechanical trauma can induce widespread chondrocyte death, potentially leading to irreversible breakdown of the joint and the onset of osteoarthritis. Additionally, maintenance of chondrocyte viability is important in osteochondral graft procedures for optimal surgical outcomes. We present a method to assess the spatial extent of cell injury/death on the articular surface of intact murine synovial joints after application of controlled mechanical loads or impacts. This method can be used in comparative studies to investigate the effects of different mechanical loading regimens, different environmental conditions or genetic manipulations, as well as different stages of cartilage degeneration on short- and/or long-term vulnerability of in situ articular chondrocytes. The goal of the protocol introduced in the manuscript is to assess the spatial extent of cell injury/death on the articular surface of murine synovial joints. Importantly, this method enables testing on fully intact cartilage without compromising native boundary conditions. Moreover, it allows for real-time visualization of vitally stained articular chondrocytes and single image-based analysis of cell injury induced by application of controlled static and impact loading regimens. Our representative results demonstrate that in healthy cartilage explants, the spatial extent of cell injury depends sensitively on load magnitude and impact intensity. Our method can be easily adapted to investigate the effects of different mechanical loading regimens, different environmental conditions or different genetic manipulations on the mechanical vulnerability of in situ articular chondrocytes.

We present a method to assess the spatial extent of cell injury/death on the articular surface of intact murine joints after application of controlled mechanical loads or impacts. This method can be used to investigate how osteoarthritis, genetic factors and/or different loading regimens affect the vulnerability of in situ chondrocytes.

全完整型小鼠软骨外种机械负荷对软骨细胞损伤的实时可视化与分析

Homeostasis of articular cartilage depends on the viability of resident cells (chondrocytes). Unfortunately, mechanical trauma can induce widespread ...

生物工程

An Intramedullary Locking Nail for Standardized Fixation of Femur Osteotomies to Analyze Normal and Defective Bone Healing in Mice

Bone healing models are essential to the development of new therapeutic strategies for clinical fracture treatment. Furthermore, mouse models are becoming more commonly used in trauma research. They offer a large number of mutant strains and antibodies for the analysis of the molecular mechanisms behind the highly differentiated process of bone healing. To control the biomechanical environment, standardized and well-characterized osteosynthesis techniques are mandatory in mice. Here, we report on the design and use of an intramedullary nail to stabilize open femur osteotomies in mice. The nail, made of medical-grade stainless steel, provides high axial and rotational stiffness. The implant further allows the creation of defined, constant osteotomy gap sizes from 0.00 mm to 2.00 mm. Intramedullary locking nail stabilization of femur osteotomies with gap sizes of 0.00 mm and 0.25 mm result in adequate bone healing through endochondral and intramembranous ossification. Stabilization of femur osteotomies with a gap size of 2.00 mm results in atrophic non-union. Thus, the intramedullary locking nail can be used in healing and non-healing models. A further advantage of the use of the nail compared to other open bone healing models is the possibility to adequately fix bone substitutes and scaffolds in order to study the process of osseous integration. A disadvantage of the use of the intramedullary nail is the more invasive surgical procedure, inherent to all open procedures compared to closed models. A further disadvantage may be the induction of some damage to the intramedullary cavity, inherent to all intramedullary stabilization techniques compared to extramedullary stabilization procedures.

This protocol describes an osteosynthesis technique using an intramedullary locking nail for standardized fixation of femur osteotomies, which can be used to analyze normal and defective bone healing in mice.

髓内锁钉股骨截骨标准化固定用于分析正常和有缺陷的骨愈合小鼠

Bone healing models are essential to the development of new therapeutic strategies for clinical fracture treatment. Furthermore, mouse models are becoming ...

In Vivo Evaluation of Fracture Callus Development During Bone Healing in Mice Using an MRI-compatible Osteosynthesis Device for the Mouse Femur

Endochondral fracture healing is a complex process involving the development of fibrous, cartilaginous, and osseous tissue in the fracture callus. The amount of the different tissues in the callus provides important information on the fracture healing progress. Available in vivo techniques to longitudinally monitor the callus tissue development in preclinical fracture-healing studies using small animals include digital radiography and &#181;CT imaging. However, both techniques are only able to distinguish between mineralized and non-mineralized tissue. Consequently, it is impossible to discriminate cartilage from fibrous tissue. In contrast, magnetic resonance imaging (MRI) visualizes anatomical structures based on their water content and might therefore be able to noninvasively identify soft tissue and cartilage in the fracture callus. Here, we report the use of an MRI-compatible external fixator for the mouse femur to allow MRI scans during bone regeneration in mice. The experiments demonstrated that the fixator and a custom-made mounting device allow repetitive MRI scans, thus enabling longitudinal analysis of fracture-callus tissue development.

In Vivo Evaluation of Fracture Callus Development During Bone Healing in Mice Using an MRI-compatible Osteosynthesis Device for the Mouse Femur

The evaluation of tissue development in the fracture callus during endochondral bone healing is essential to monitor the healing process. Here, we report the use of a magnetic resonance imaging (MRI)-compatible external fixator for the mouse femur to allow MRI scans during bone regeneration in mice.

在体内MRI 对小鼠股骨骨愈合过程中骨折愈伤组织发育的评价

Endochondral fracture healing is a complex process involving the development of fibrous, cartilaginous, and osseous tissue in the fracture callus. The ...

A Mouse Model of Orthopedic Surgery to Study Postoperative Cognitive Dysfunction and Tissue Regeneration

Surgery is commonly used to improve and maintain quality of life. Unfortunately, in vulnerable patients such as the elderly, complications may occur and significantly diminish the outcome. Indeed, after routine orthopedic surgery to repair a fracture, as many as 50% of elderly patients suffer from neurologic complications like delirium. Also, the capacity to heal and regenerate tissue after surgery decreases with age, and can impact the quality of fracture repair and even osseous integration of implants. Thus, a better understanding of mechanisms that drive these age-dependent changes could provide strategic targets to minimize risk for such complications and optimize outcomes. Here, we introduce a clinically relevant mouse model of tibial fracture. The postoperative changes in these mice mimic some of the cognitive impairments commonly observed after routine orthopedic surgery in humans. Briefly, an incision is performed in the right hind limb under strictly aseptic conditions. Muscles are disassociated, and a 0.38-mm stainless steel pin is inserted into the upper crest of the tibia, inside the intramedullary canal. Osteotomy is then performed, and the wound is stapled. We have used this model to investigate the effects of surgical trauma on postoperative neuroinflammation and behavioral changes. By applying this fracture model in combination with parabiosis, a surgical model in which 2 mice are anastomosed, we have studied cells and secreted factors that systemically rejuvenate organ function and tissue regeneration after injury. By following our step-by-step protocol, these models can be reproduced with high fidelity, and can be adapted to interrogate many biologic pathways that are altered by surgical trauma.

This protocol describes a mouse model of orthopedic surgery that has been used to study mechanisms of postoperative neuroinflammation and behavioral changes, and when combined with parabiosis, to study tissue regeneration during aging.

骨科手术的小鼠模型研究术后认知功能障碍与组织再生

Surgery is commonly used to improve and maintain quality of life. Unfortunately, in vulnerable patients such as the elderly, complications may occur and ...

The Generation of Closed Femoral Fractures in Mice: A Model to Study Bone Healing

Bone fractures impose a tremendous socio-economic burden on patients, in addition to significantly affecting their quality of life. Therapeutic strategies that promote efficient bone healing are non-existent and in high demand. Effective and reproducible animal models of fractures healing are needed to understand the complex biological processes associated with bone regeneration. Many animal models of fracture healing have been generated over the years; however, murine fracture models have recently emerged as powerful tools to study bone healing. A variety of open and closed models have been developed, but the closed femoral fracture model stands out as a simple method for generating rapid and reproducible results in a physiologically relevant manner. The goal of this surgical protocol is to generate unilateral closed femoral fractures in mice and facilitate a post-fracture stabilization of the femur by inserting an intramedullary steel rod. Although devices such as a nail or a screw offer greater axial and rotational stability, the use of an intramedullary rod provides a sufficient stabilization for consistent healing outcomes without producing new defects in the bone tissue or damaging nearby soft tissue. Radiographic imaging is used to monitor the progression of callus formation, bony union, and subsequent remodeling of the bony callus. Bone healing outcomes are typically associated with the strength of the healed bone and measured with torsional testing. Still, understanding the early cellular and molecular events associated with fracture repair is critical in the study of bone tissue regeneration. The closed femoral fracture model in mice with intramedullary fixation serves as an attractive platform to study bone fracture healing and evaluate therapeutic strategies to accelerate healing.

The murine closed femoral fracture model is a powerful platform to study fracture healing and novel therapeutic strategies to accelerate bone regeneration. The goal of this surgical protocol is to generate unilateral closed femoral fractures in mice using an intramedullary steel rod to stabilize the femur.

小鼠闭合性股骨骨折的形成: 骨愈合模型的研究

Bone fractures impose a tremendous socio-economic burden on patients, in addition to significantly affecting their quality of life. Therapeutic strategies ...

Transverse Fracture of the Mouse Femur with Stabilizing Pin

Fracture repair is an essential function of the skeleton that cannot be reliably modeled in vitro. A mouse injury model is an efficient approach to test whether a gene, gene product or drug influences bone repair because murine bones recapitulate the stages observed during human fracture healing. When a mouse or human breaks a bone, an inflammatory response is initiated, and the periosteum, a stem cell niche surrounding the bone itself, is activated and expands. Cells residing in the periosteum then differentiate to form a vascularized soft callus. The transition from the soft callus to a hard callus occurs as the recruited skeletal progenitor cells differentiate into mineralizing cells, and the bridging of the fractured ends results in the bone union. The mineralized callus then undergoes remodeling to restore the original shape and structure of the healed bone. Fracture healing has been studied in mice using various injury models. Still, the best way to recapitulate this entire biological process is to break through the cross-section of a long bone that encompasses both cortices. This protocol describes how a stabilized, transverse femur fracture can be safely performed to assess healing in adult mice. A surgical protocol including detailed harvesting and imaging techniques to characterize the different stages of fracture healing is also provided.

This protocol describes a method to perform fractures on adult mice and monitor the healing process.

带稳定针的小鼠股骨横断

Fracture repair is an essential function of the skeleton that cannot be reliably modeled in vitro. A mouse injury model is an efficient approach to test ...

生物学

Establishing a Diaphyseal Femur Fracture Model in Mice

Bones have a significant regenerative capacity. However, fracture healing is a complex process, and depending on the severity of the lesions and the age and overall health status of the patient, failures can occur, leading to delayed union or nonunion. Due to the increasing number of fractures resulting from high-energy trauma and aging, the development of innovative therapeutic strategies to improve bone repair based on the combination of skeletal/mesenchymal stem/stromal cells and biomimetic biomaterials is urgently needed. To this end, the use of reliable animal models is fundamental to better understanding the key cellular and molecular mechanisms that determine the healing outcomes. Of all the models, the mouse is the preferred research model because it offers a wide variety of transgenic strains and reagents for experimental analysis. However, the establishment of fractures in mice may be technically challenging due to their small size. Therefore, this article aims to demonstrate the procedures for the surgical establishment of a diaphyseal femur fracture in mice, which is stabilized with an intramedullary wire and resembles the most common bone repair process, through cartilaginous callus formation.

This protocol describes a surgical procedure for the establishment of a diaphyseal fracture in the femur of mice, which is stabilized with an intramedullary wire, for fracture healing studies.

建立小鼠骨干股骨骨折模型

Bones have a significant regenerative capacity. However, fracture healing is a complex process, and depending on the severity of the lesions and the age ...

<meta charset="utf8"></head><body>小鼠骨修复的标准化下颌骨骨折方案

Less-Invasive Technique for Non-stabilized Mandibular Fracture in Mouse Models

Non-stabilized fractures can be made at mandibular sites in mice, thus making it possible to analyze bone repair using an endochondral ossification mode. To most accurately reflect this process in vivo, it is necessary to have a standardized protocol to avoid excessive bone loss and soft tissue damage, particularly at the mandibular site, an anatomical site characterized by minimal access. To our knowledge, we describe for the first time a less-invasive protocol of non-stabilized mandibular fracture in mice. Adult mice are anesthetized with isoflurane and receive a preoperative dose of buprenorphine by subcutaneous injection. A submandibular approach is performed, with a skin incision made along the inferior border of the mandible. The masseter muscle is elevated in a subperiosteal plane along the mandibular ramus with a periosteal elevator. A vertical and complete fracture of the ramus is performed from the basilar border to the coronoid notch (between condylar and coronoid processes), using a piezoelectric bone surgery device under saline serum irrigation at the basilar edge and scissors to complete the fracture of the mandibular ramus. The skin approach is closed by silk sutures. This detailed procedure for non-stabilized mandibular fractures offers an efficient procedure allowing minimal bone loss and soft tissue damage. This technique ensures successful and consistent results to accurately reflect the process of endochondral bone repair in mouse models.

<meta charset="utf8"></head><body>小鼠模型中非稳定下颌骨骨折的微创技术

This protocol presents a comprehensive and efficient method for analyzing mandibular bone repair. We describe a reproducible technique for non-stabilized mandibular fracture in a mouse model, allowing analysis of the process of endochondral bone repair with minimal tissue damage and bone loss.

小鼠模型中非稳定下颌骨骨折的微创技术

Non-stabilized fractures can be made at mandibular sites in mice, thus making it possible to analyze bone repair using an endochondral ossification mode. ...