Effect of Eccentric Contraction on Satellite Cell Activation in Human Vastus Lateralis Muscle

我们研究了阶梯运动后股外侧肌（VL）SC激活的时间过程。11名未经训练的年轻人参加了一个30分钟的阶梯式上/下运动方案，主要涉及右腿的同心收缩和左腿的离心收缩。分别于运动前、运动后第2天和第5天取双侧VL肌活检。通过免疫荧光染色确定每种纤维类型的SC数量。采用实时荧光定量RT-PCR技术检测细胞中几种mRNA的表达。运动后两侧VL肌中各类型肌纤维的SC数量无明显变化。运动后2- 5d，左VL肌HGF mRNA表达显著增加，5d后，左VL肌Myostatin mRNA表达也显著增加，而右VL肌无明显变化。IL-6、MyoD和IGF-I mRNA的表达在运动后左侧VL略有增加，但在右侧VL肌肉中没有增加。

We investigated the time-course of SC activation in vastus lateralis (VL) muscle after step exercise. Eleven non-trained young adults participated in a 30-minute step up/down exercise protocol involving mainly concentric contractions with right leg and mainly eccentric contractions with left leg. Biopsy samples were taken from the both side of VL muscles before exercise, and 2 and 5 days after exercise. The numbers of SCs for each fiber type were determined by using immunofluorescence staining. The expressions of several mRNA were analyzed using real-time RT-PCR system. The numbers of SCs in both side VL muscles did not changed in all fiber types after exercise. The expressions of HGF mRNA increased significantly at 2-5 days and the expression of myostatin mRNA also increased at 5 days after exercise in left VL, but not in right VL muscles. The expressions of IL-6, MyoD, and IGF-I mRNA slightly increased in left VL, but not in right VL muscles after exercise.