自噬在不同强度运动影响关节软骨细胞功能中的作用

摘要

目的：探讨自噬在不同运动强度影响关节软骨细胞功能中的作用。方法：将 SD 大鼠随机分为4组：高强度运动组、中等强度运动组、低强度运动组和对照组，其中的三个运动组大鼠均进行每天1 h 持续8 w 的跑台运动，运动速度分别为35 m ／min、25 m ／min、15 m ／min，对照组不进行运动干预。分组干预结束后处死大鼠，取左后肢膝关节软骨组织提取总 RNA和蛋白，利用 qRT －PCR 法检测蛋白多糖和 II 型胶原纤维 mRNA 水平，利用 Western blot 法测定自噬相关标志蛋白 Beclin －1和微管相关蛋白1轻链3（microtubule －associated protein 1light chain 3，LC3）的蛋白水平。结果：与对照组相比，低强度和中等强度运动组大鼠膝关节软骨外观无明显差异，蛋白多糖和 II 型胶原纤维 mRNA 水平以及 Beclin －1和 LC3－II ／I 蛋白水平明显升高；而高强度运动组大鼠膝关节中出现少量积液，滑膜肿胀，关节软骨表面出现散在微小裂痕和纤维化表现，蛋白多糖和 II 型胶原纤维 mRNA 水平以及 Beclin －1和 LC3－II ／I 蛋白水平显著降低。结论：低强度和中等强度运动可以通过促进自噬维持软骨细胞分泌功能，而高强度运动则会诱发自噬缺陷并造成软骨组织破坏。%Objective:To determine the role of autophagy in the regulation of articular chondrocyte function with exercises of different intensity.Methods:The rats were randomly divided into 4 groups:high,moderate,low intensity exercise groups and the control group.The rats of exercise groups were trained in the form of treadmill running,1 h /d for 8 weeks,with 35 m /min,25 m /min,and 15 m /min respectively.And the rats of the control group were not trained at all.Finally,the knee articular cartilage of the left hind limb was harvested to determine the mRNA level of proteoglycan and type II collagen,and the protein level of Beclin -1 and microtubule -associated protein 1 light chain 3 (LC3).Results:Compared with the control group,the gross appearance of the cartilage did not differ in the rats of moderate and low intensity exercise groups.And the mRNA levels of proteo-glycan and type II collagen and the protein level of Beclin -1 and LC3 -II /I were all significantly upregulated.As a contrast,the mRNA and protein levels of those proteins were all significantly de-creased,accomplished with arthroedema and cartilage destruction.Conclusion:The secretory function of the chondrocyte may be improved by low to moderate intensity exercise via an autophagy -de-pendent manner;however,autophagy defect may be induced by high intensity exercise to mediate cartilage destruction.