Department of Physiotherapy, Federal University of São Carlos, São Carlos, São Paulo, Brazil.
Connect Tissue Res. 2012;53(1):39-47. doi: 10.3109/03008207.2011.610476. Epub 2011 Sep 20.
The aim of study was to evaluate the progression of the ankle articular cartilage alterations after a post-immobilization muscle stretching. Twenty-nine Wistar rats were separated into five groups: C--control, S--stretched, SR--stretch recovery, IS--immobilized and stretched, and ISR--immobilized stretched recovery. The immobilization was maintained for 4 weeks and the left ankle was then stretched manually through a full dorsal flexion for 10 times for 60 s with a 30 s interval between each 60 s period, 7 days/week for 3 weeks. The recovery period was of 7 weeks. At the end of the experiment, the left ankles were removed, processed in paraffin, and stained in hematoxylin-eosin and safranin O. Two blinded observers evaluated the articular cartilage using the Mankin grading system (cellularity, chondrocyte cloning, and proteoglycan content) through light microscopy, and performed the morphometry (cellularity, total thickness, non-calcified thickness, and calcified thickness measures). Both the Mankin grading system and the morphometric analysis showed that the ISR group presented the most increased cellularity among the groups. The IS and SR groups showed the highest proteoglycan loss, and the ISR group showed the same content of proteoglycan observed in the C group. No significant differences were found in the chondrocyte cloning, the total cartilage thickness, the non-calcified cartilage thickness, and the calcified cartilage thickness among the groups. The results suggest that the cartilage can recover the proteoglycan loss caused by immobilization and stretching, probably because of the increased chondrocyte density. Therefore, the ankle articular cartilage responded as to repair the metabolic deficits.
研究目的在于评估踝关节软骨在固定后肌肉拉伸后的变化进展。29 只 Wistar 大鼠被分为五组：C-对照组、S-拉伸组、SR-拉伸恢复组、IS-固定和拉伸组以及 ISR-固定和拉伸恢复组。固定持续 4 周，然后通过手动将左踝关节完全背屈 10 次，每次 60 秒，间隔 30 秒，每周 7 天，持续 3 周。恢复期为 7 周。实验结束时，取出左踝关节，用石蜡包埋，用苏木精-伊红和番红 O 染色。两名盲法观察者使用 Mankin 分级系统（细胞数量、软骨细胞克隆和蛋白聚糖含量）通过光镜评估关节软骨，并进行形态计量学（细胞数量、总厚度、非钙化厚度和钙化厚度测量）。Mankin 分级系统和形态计量分析均显示，ISR 组的细胞数量增加最多。IS 和 SR 组的蛋白聚糖丢失最多，而 ISR 组的蛋白聚糖含量与 C 组相同。各组间软骨细胞克隆、总软骨厚度、非钙化软骨厚度和钙化软骨厚度均无显著差异。结果表明，软骨可以恢复因固定和拉伸而导致的蛋白聚糖丢失，这可能是由于软骨细胞密度增加所致。因此，踝关节软骨对代谢缺陷做出了修复反应。
