自主运动对高脂饮食诱导的肥胖小鼠膝骨关节炎软骨形态学的影响

Effect of voluntary exercise on cartilage morphology of knee osteoarthritis in obese mice induced by high-fat diet

目的研究高脂饮食诱导的骨性关节炎发生过程中骨关节软骨病变以及自主运动对骨性关节炎软骨的影响机制,探讨自主运动对膝骨关节炎软骨的保护作用,为临床治疗膝骨关节炎提供有效的实验证据。方法将28只C57BL/6J小鼠随机分为正常饮食组(C-Sed组,n=6)、正常饮食加运动组(C-Ex组,n=6)、高脂饮食组(HF-Sed组,n=8)及高脂饮食加运动组(HF-Ex组,n=8)。C-Sed组和C-Ex组喂养基础饲料(13.5%Kcal),HF-Sed组和HF-Ex组喂养高脂饲料(60%Kcal)。喂养8周后,C-Ex组和HF-Ex组小鼠采用自主转轮运动进行干预,记录运动数据,运动3周后行颈椎脱臼处死;C-Sed组和HF-Sed组小鼠不进行运动干预,继续喂养不同膳食4周后行颈椎脱臼处死,取膝关节软骨组织进行固定、脱钙,制成4μm厚石蜡切片,并进行HE及甲苯胺蓝染色,测量各组小鼠软骨层厚度,探究自主转轮运动对肥胖小鼠膝骨关节炎软骨形态学的影响。结果喂养12周结束后,与C-Sed组小鼠相比,HF-Sed组小鼠体重明显增加,高脂饮食成功诱导了高脂饮食组小鼠发生肥胖,且经HE及甲苯胺蓝染色后,可观察到与C-Sed组小鼠相比,HF-Sed组小鼠软骨表面粗糙、部分缺损,软骨层厚度降低(P<0.001);而HF-Ex组较HF-Sed组小鼠关节软骨表面光滑,软骨层厚度增加,Mankin评分分值降低。结论3周自主转轮运动可增加高脂组小鼠软骨层厚度,降低Mankin评分分值,延缓骨关节炎软骨退变,起到保护关节软骨的作用。

Objective To examine the effect of voluntary wheel-running exercise on cartilage morphology of knee osteoarthritis (KOA) in obese mice induced by high-fat diet, to explore the protective role of 3 weeks voluntary wheel-running exercise on KOA, and to provide effective experimental evidence for the clinical treatment of knee osteoarthritis. Methods C57BL/6 J mice were randomly assigned to the control diet (C-Sed) group, control diet exercise (C-Ex) group, high-fat diet (HF-Sed) group and high-fat diet exercise (HF-Ex) group. The control diet groups were fed a control diet (13.5% kcal from fat), and the high-fat diet groups were fed a high-fat diet (60% kcal from fat). After feeding 8 weeks of different diets, the exercise groups were started running. The exercise lasted for three weeks, and then the mice were sacrificed by cervical dislocation. The C-Sed and HF-Sed groups did not receive exercise intervention;they received feeding for four weeks then sacrificed. In order to examine the effect of voluntary wheel-running exercise on cartilage morphology of KOA, the joint of knee were harvested and fixed, decalcified and embedded in paraffin, and four-micrometer-thick sections were stained with both HE and toluidine blue. Results After twelve weeks of feeding of different diets, the body mass of the high-fat diet group mice increased significantly, which demonstrates that high-fat diet could successfully induce obesity in mice. From the result of HE and toluidine blue stain, in comparison to the C-Sed group, the surface of the knee articular cartilage in the HF-Sed group was rough and has partial defect, and the thickness of articular cartilage has a significant decrease ( P <0.001);contrary to the HF-Sed group, the surface of the knee articular cartilage in HF-Ex group was smooth, with significant increase in cartilage thickness and lower Mankin score. Conclusion Three weeks voluntary wheel-running exercise can increase cartilage thickness, decrease the Mankin score and delay the degeneration of knee cartilage in obese mice. To conclude, the short-term wheel-running exercise protects against obesity-induced KOA.