Zhou Chen-Xu, Wang Feng, Zhou Yun, Fang Qiao-Zhou, Zhang Quan-Bing
Department of Rehabilitation Medicine, The Second Affiliated Hospital of Anhui Medical University, Hefei 230601, Anhui Province, China.
The Second Clinical Medicine College, Anhui Medical University, Hefei 230000, Anhui Province, China.
World J Orthop. 2023 Sep 18;14(9):669-681. doi: 10.5312/wjo.v14.i9.669.
Current research lacks a model of knee extension contracture in rats.
To elucidate the formation process of knee extension contracture.
We developed a rat model using an aluminum external fixator. Sixty male Sprague-Dawley rats with mature bones were divided into the control group ( = 6) and groups that had the left knee immobilized with an aluminum external fixator for 1, 2, and 3 d, and 1, 2, 3, 4, 6, and 8 wk ( = 6 in each group). The passive extension range of motion, histology, and expression of fibrosis-related proteins were compared between the control group and the immobilization groups.
Myogenic contracture progressed very quickly during the initial 2 wk of immobilization. After 2 wk, the contracture gradually changed from myogenic to arthrogenic. The arthrogenic contracture progressed slowly during the 1 week, rapidly progressed until the 3 week, and then showed a steady progression until the 4 week. Histological analyses confirmed that the anterior joint capsule of the extended fixed knee became increasingly thicker over time. Correspondingly, the level of transforming growth factor beta 1 (TGF-β1) and phosphorylated mothers against decapentaplegic homolog 2 (p-Smad2) in the anterior joint capsule also increased with the immobilization time. Over time, the cross-sectional area of muscle fibers gradually decreased, while the amount of intermuscular collagen and TGF-β1, p-Smad2, and p-Smad3 was increased. Unexpectedly, the amount of intermuscular collagen and TGF-β1, p-Smad2, and p-Smad3 was decreased during the late stage of immobilization (6-8 wk). The myogenic contracture was stabilized after 2 wk of immobilization, whereas the arthrogenic contracture was stabilized after 3 wk of immobilization and completely stable in 4 wk.
This rat model may be a useful tool to study the etiology of joint contracture and establish therapeutic approaches.
目前的研究缺乏大鼠膝关节伸直挛缩模型。
阐明膝关节伸直挛缩的形成过程。
我们使用铝制外固定器建立了大鼠模型。将60只骨骼成熟的雄性Sprague-Dawley大鼠分为对照组（n = 6）以及左膝关节用铝制外固定器固定1、2和3天，以及1、2、3、4、6和8周的组（每组n = 6）。比较对照组和固定组之间的被动伸展活动范围、组织学以及纤维化相关蛋白的表达。
在固定的最初2周内，肌源性挛缩进展非常迅速。2周后，挛缩逐渐从肌源性转变为关节源性。关节源性挛缩在第1周进展缓慢，直到第3周迅速进展，然后在第4周之前呈稳定进展。组织学分析证实，伸直固定膝关节的前关节囊随着时间的推移变得越来越厚。相应地，前关节囊中转化生长因子β1（TGF-β1）和磷酸化的抗五肢瘫同源物2（p-Smad2）水平也随着固定时间增加。随着时间的推移，肌纤维横截面积逐渐减小，而肌间胶原蛋白以及TGF-β1、p-Smad2和p-Smad3的量增加。出乎意料的是，在固定后期（6 - 8周），肌间胶原蛋白以及TGF-β1、p-Smad2和p-Smad3的量减少。固定2周后肌源性挛缩稳定，而关节源性挛缩在固定3周后稳定，并在4周时完全稳定。
该大鼠模型可能是研究关节挛缩病因和建立治疗方法的有用工具。
