过度运动对大鼠膝关节损伤的机理探究

A study on mechanism of excessive exercise-induced knee joint injuries in rats

[目的]探讨过度运动致膝关节滑膜和软骨损伤的形态改变及其损伤机理。[方法]将25只健康成年Wistar雄性大鼠随机分为正常对照组(对照组)与过度运动训练(跑步)组(训练组),分别于1、2、3、6周时处死大鼠,取全膝关节,4%PFA(多聚甲醛)液固定、CT扫描、石蜡包埋、切片、染色;通过肉眼观察、CT成像、Masson三色胶原、Safranin-O、ED1、α-SMA等(免疫)染色观察滑膜、软骨形态学变化;并用病理图像、半定量法、Mankin's评分等进行测定并分析其组织病理学改变。[结果]训练组膝关节软骨表面破坏严重,软骨下骨骨密度明显增高。Mankin's评分对照组(0.43±0.3)分,训练组(5.9±2.1)分(15 km),(7.9±2.7)分(30km);滑膜纤维性病变,对照组Collgen fibers阳性胶原纤维(9.7±2.3)%,训练组(34.5±3.7)%(15 km),(67.5±4.2)%(30 km);对照组ED1阳性细胞半定量(4.8±1.7)分,训练组为(17.3±3.5)个/mm2(10 km),(13.46±2.7)个/mm2(30 km);对照组α-SMA阳性细胞半定量(92.3±13.6)分,训练组为(287.2±21.3)个/mm2(5 km),(441.4±100.4)个/mm2(30 km);对照组与训练组软骨及滑膜的病理改变差异具有统计学意义(*P<0.05;**P<0.01)。[结论]反复过度运动能导致膝关节滑膜炎、滑膜纤维化以及进行性关节软骨破坏等病理改变,并最终发展为骨关节炎。

[ Objective] To investigate the morphological changes and mechanism of knee joint synovial and cartilage injuries induced by excessive exercise. [ Method] Twentyfive healthy male adult Wistar rats were randomly divided into control group and excessive exercise （running） group. Rats were sacrificed at 1,2, 3, or 6 weeks. The whole knee joint was collected and fixed in 4% paraformaldehyde （PFA）, followed by computed tomography （CT） scanning, paraffin embedding, section, and staining. The morphological changes in synovial membrane and cartilage were observed with the naked eye, CT scanning, Masson trichrome staining, safranin O staining, ED1 staining, and a- smooth muscle actin （a- SMA） immunostaining. The histopathological changes were evaluated and analyzed using pathological imaging, semi - quantitative method, and Mankin＇s grading system. [ Result] In the exercise group, the surface of knee joint cartilage was seriously damaged and the density of subchondral bone was substantially increased compared with the control group. Mankin＇s grade was significantly higher in the exercise group than in the control group （ 15 km ： 5.9± 2.1 vs 0. 43 ±0. 3,P 〈 0. 05 ; 30 km ： 7.9 ± 2.7 vs 0. 43 ± 0. 3, P 〈 0.01 ）. The exercise group had extensive synovial fibrosis and the percent area covered by positive collagen fibers was significantly larger in the exercise group than in the control group （15 km： 34.5 ±3.7% vs 9.7±2.3% ,P 〈0.05; 30 kin： 67.5 ±4.2% vs9.7±2.3%,P〈0.01）. According to the semi - quantitative analysis, the number of ED1 - positive cells per ram2 was significantly larger in the exercise group than in the control group （ 10 km ： 17.3 ±3.5 vs 4.8 ±1.7, P 〈0.05; 30 kin： 13.46 ±2.7 vs4.8 ± 1.7,P 〈0.05） ; the number of a - SMA - positive cells per mm2 was also signifi-cantly larger in the exercise group than in the control group （5 km：287.2±21.3 vs 92.3 ± 13.6 ,P 〈0.05 ; 30 km：441.4 ＋100.4 vs 92.3 ± 13.6, P 〈0. 01 ）. [ Conclusion ] Excessive exercise can cause pathological changes in the knee joint, including synovitis, synovial fibrosis, and progressive destruction of articular cartilage, which finally result in osteoarthritis.