不同负荷长期跑台运动对大鼠腓肠肌calpains和calpastatin mRNA及活性表达的影响

Effect of Different Load of Treadmill Running on mRNA and Activity Expression of Calpains and Calpastatin in Gastrocnemius Muscle of Rats

目的:研究不同负荷长期跑台运动对大鼠腓肠肌中calpains及calpastatin表达的影响。方法:将大鼠随机分为对照组(不运动)和运动组,运动组又分为大负荷和小负荷组,这两组均进行3周、5周、7周和9周的不同负荷长期跑台运动。取大鼠右后肢腓肠肌,测定calpains及calpastatin mRNA和蛋白表达。结果:两种负荷运动后肌纤维均出现损伤和炎症反应,损伤程度两种负荷组类似,大负荷组炎症反应稍轻。m-calpain活性在大负荷和小负荷运动3周和5周后比对照组显著升高;-μcalpain活性在小负荷运动3周、5周和大负荷运动3周、5周和7周后比对照组显著下降。n-calpain活性运动后呈下降趋势,但与对照组相比,无显著性差异。μ-calpain和m-calpain的mRNA表达水平与对照组相比均无明显改变,n-calpain mRNA表达在小负荷运动3周和大负荷运动5后比对照组下降。结论:m-calpain与-μcalpain、n-calpain在运动后呈现不同的变化趋势,调节机制不尽相同,升高的m-calpain活性在运动性肌肉损伤过程中可能起到重要作用,长时间重复性运动可使m-calpain对运动产生适应。-μcalpain在长期跑台运动后并未表现出明显差异,n-calpain活性的下降及calpastatin活性的升高可能与肌肉损伤有关。

Objective To investigate the effect of treadmill running on mRNA and activity expression of calpains and calpastatin expression in gastrocnemius muscle of rats. Methods Rats were assigned to control and exercise groups. Rats in exercise groups undertook treadmill running in different loads for 3, 5, 7, 9 weeks. Calpains system （μ-calpain, m-calpain, n-ealpain and calpastatin） were measured in all groups. Results Rats in exercise groups showed muscle fiber damage and inflammation reaction, m-ealpain activity increased after 3 and 5 weeks treadmill running and μ-calpain activity decreased after 3, 5 weeks low volume exercise and 3, 5, and 7 weeks high volume exercise compared with the control. Compared with controls, n-calpain activity showed no statistical changes after exercise and n-calpain mRNA was down-regulated after 3 weeks mild and 5 weeks high load exercise. Conclusions The increased activity of m-calpain might associate with early exercise-induced skeletal muscle damage. Treadmill running stimulated the adaptations of m-calpain in muscles. The decrease of n-calpain activity and the increase of calpastatin might relate to muscle injury.