游泳训练后大鼠骨骼肌细胞自由基代谢、线粒体膜电位变化与细胞凋亡的关系

目的 :研究游泳训练前后大鼠骨骼肌自由基代谢、线粒体膜电位变化与细胞凋亡的关系 ,寻找评定运动性疲劳与恢复的可行性指标。方法 :5 0只雄性SD大鼠 (10 0± 5 )g ,随机分为对照组 (G1)、训练 1天组 (G2 )、训练 6天组 (G3 )、训练 12天组 (G4 )、训练 18天组 (G5)。用流式细胞仪检测肌细胞线粒体膜电位、DNA倍体分析 ,MDA测定采用硫代巴比妥酸比色法 ,SOD测定使用放免法 ,JEM - 12 0 0EX电镜及脱氧核糖核苷酸末端转移酶介导的缺口末端标记技术 (TUNEL)检测细胞凋亡。结果 :游泳训练后各组骨骼肌细胞线粒体膜电位均发生改变 ,G3 组最低。运动后G3 、G5组的DNA出现凋亡峰。TUNEL染色显示 ,游泳训练后大鼠骨骼肌呈棕黄色的凋亡细胞明显增加 ,G3组比例最高。各训练组之间SOD活性变化差异显著 ,G3 、G4 组MDA数量显著升高。电镜观察G3组肌细胞溶酶体增多 ,部分线粒体嵴消失 ,但膜完整 ,形似空泡 ,枯否细胞活跃。G5组肌细胞的超微结构似G3 组 ,细胞完整。结论 :游泳训练可诱发细胞凋亡 ,不同运动负荷对线粒体膜电位、MDA、SOD的影响各异 ,运动引起线粒体膜电位下降的同时可导致细胞凋亡。线粒体膜电位、SOD/MDA比值变化可能是诱导细胞凋亡的关键因素之一

The Relation of the Change in Free Radical Metabolism and Mitochondrial Membrane Potential to Apoptosis of Skeletal Muscular Cell in Rats after Swim Exercise

Objective In this paper,we investigated a possible marker for evaluating the exercise-induced fatigue and its recovery, thus the relation of the changes in free radical metabolism, mitochondrial membrane potential in skeletal muscular cell to the apoptosis after swim exercise was investigated. Methods Fifty male SD rats were randomly divided into five groups: G 1 control group, group G 2 to G 5, swimming training for 1, 6, 12 and 18 days, respectively.Mitochondrial membrane potential in the skeletal muscular cell and DNA double analysis was determined by the technique of flow cytometry. MDA,SOD was determined by sulfobarbituric acid colorimetric analysis and radioimmunity, respectively. Apoptosis was observed with JEM-1200EX electric microscope and terminal deoxynucleotidyl transferase mediated d-UTP nick end labeling (TUNEL). Results The mitochondrial membrane potential changed in all groups and the value in G 3 was the lowest. The DNA in G 3 and G 5 appeared the peak of apoptosis after exercise. TUNEL showed that the apoptosis percentage in orange muscle increased significantly, and the apoptosis percentage in G 3 was the highest. The changes in SOD activity were different among groups.The quantity of MDA in G 3 and G 4 increased significantly. The results of electric microscoply showed that the muscular cell lysosme increased and some mitochondrial crest disappeared, while the muscular cell membrane remained integrited and vacuolated. The Kupffer was active. The ultrastructure of skeletal muscular cell in G 5 was familiar with that in G 3. Conclusion Swimming could induce apoptosis. Different exercise load had different influence on mitochondrual membrane potential, MDA and SOD. Exercise could cause the change in mitochondrial membrane potential, which in turn induced muscular apoptosis. The mitochondral membrane potential and the ratio of SOD/MDA was probably the main factor for inducing apoptosis, and can be used for evaluating the exercise-induced fatigue.