Objective: To investigate the repair effect and JNK/NF-κB,SOX9 mechanisms of vibration exercise with different frequencies on articular cartilage in rats with early knee osteoarthritis. Methods: Forty-eight adult male SD rats were randomly divided into six groups(n=8):model control group(MC),high frequency vibration group 1 (GP1,60 Hz),high frequency vibration 2 group (GP2,40 Hz),medium frequency vibration group (ZP,20 Hz),minor frequency group(DP,10 Hz)and normal control group(NC). Except for NC group,the rats in each group were made into early knee osteoarthritis model after six weeks of knee joint cavity injection of papain solution and 2% mixture l-cysteine on the 1st,4 th and 7th day. Each exercise group was subjected vibration to 40 minutes a day with amplitude of 2～5 mm and 5 days a week. Four weeks later, the articular cartilage of the lateral femoral condyle of the both back leg knee joints were detected by HE staining,serine O staining and Mankin scores for morphological observation. The expression levels of JNK,NF-κB p65 and Sox9 mRNA in articular cartilage of the medial femoral condyle were detected by RT-qPCR,and the protein expressions of JNK,NF-κB p65 and Sox9 were detected by Western blot. Results: Compared with the NC group,the Mankin score in other groups was significantly higher (P＜0.01). Compared with the MC group,the Mankin score of each vibration group was significantly lower(P＜0.05),the mRNA and protein expressions of JNK and NF-κB p65 in each vibration training group were significantly lower (P＜0.01),the expressions of Sox9 mRNA and protein in vibration training group were increased significantly (P＜0.01). Compared with the higher frequency group,the Mankin score,the mRNA and protein expressions of JNK and NF-κB p65 of lower frequency group were significantly lower (P＜0.05 or P＜0.01). But the expressions of Sox9 mRNA and protein were significantly higher (P＜ 0.05 or P＜0.01). Conclusion: Vibration exercise of different frequencies may present varying degrees of cartilage repair impact in rats with early knee osteoarthritis,and the cartilage repair by low-frequency vibration training is better than that by high-frequency vibration. This can be one of the mechanisms on controlling collagen synthesis by down-regulating JNK/NF-κB expression and increasing SOX9 activity of OA articular cartilage.
目的:探讨不同频率的振动训练对大鼠早期膝骨关节炎关节软骨的修复作用及其JNK/NF-κB、SOX9的机制。方法:成年雄性SD大鼠48只,随机分为6组(n=8):模型对照组(MC组),高频振动1组(GP1组,频率60 Hz),高频振动2组(GP2组,频率40 Hz)、中频振动组(ZP组,频率20 Hz)和低频振动组(DP组,频率10 Hz),正常对照组(NC组)。除正常组外,各组大鼠经第1、4、7日双后腿膝关节腔注射2%木瓜蛋白酶溶液和L-半胱氨酸混合液6周后建立早期膝骨关节炎模型后,对振动组大鼠双膝进行4周,每天 40 min,振幅2~5 mm,每周振动5 d的训练。4周后,检测双膝关节股骨外侧髁关节软骨HE染色、番红O染色和Mankin评分形态学观察,股骨内侧髁关节软骨RT-qPCR检测JNK、NF-κB p65、SOX9 mRNA,Western blot 检测JNK、NF-κB p65、SOX9蛋白表达。结果:与NC比较,其余各组Mankin评分均显著增高(P＜0.01),与MC相比,各振动组Mankin评分均显著降低(P＜0.05),其JNK、NF-κB p65mRNA和蛋白质表达显著降低(P＜0.01),SOX9mRNA和蛋白质表达显著升高(P＜0.01);与高频组相比,低频组的Mankin评分,JNK、NF-κB p65mRNA和蛋白质表达均显著降低(P＜0.05,P＜0.01),而SOX9mRNA和蛋白质表达则显著升高(P＜0.05,P＜0.01)。结论:不同频率的振动训练对早期膝骨关节炎关节软骨可表现出不同程度的修复效应,低频振动训练软骨修复优于高频振动。可能通过下调关节软骨JNK/NF-κB表达,提高SOX9活性来调控胶原合成。.
Keywords: c-Jun N-termianl kinase; knee osteoarthritis; nuclear factor kappa B; rats; sex determining region Y-box 9; vibration exercise.