有氧运动对衰老大鼠骨骼肌线粒体能量代谢的影响

目的：探讨有氧运动对衰老大鼠骨骼肌线粒体能量代谢的影响。方法：将20只12月龄的雌性Wistar大鼠随机分为老年安静组（AC，n=10）及老年运动组（AE，n=10），另取10只2月龄的雌性Wistar大鼠为青年安静组（YC，n=10）；安静组大鼠进行正常饲养，运动组大鼠进行坡度为5°，速度为15.2 m/min，第1天运动15 min、第2天运动30 min、从第3天开始每天运动45 min，每周6 d，共12周。12周后所有大鼠断头处死，取腓肠肌样本，差速离心法提取线粒体，测定SOD和GSH-Px活性、MDA含量、三羧酸循环限速酶（CS、ICD和α-KGDHC）活性及呼吸链酶复合体（RCCⅠ~Ⅳ）活性。结果：①与YC组相比，AC组骨骼肌线粒体SOD活性和MDA含量显著增加（P<0.05），CS和α-KGDHC活性均显著降低（P<0.05），RCCⅠ、RCCⅡ和RCCⅣ活性均显著下降（P<0.05），RCCⅢ活性显著升高（P<0.05）；AE组骨骼肌线粒体SOD、GSH-Px活性和MDA含量均显著增加（P<0.01），CS、ICD和α-KGDHC活性均显著升高（P<0.01），RCCⅠ~Ⅳ活性均显著升高（P<0.01）。②与AC组相比，AE组骨骼肌线粒体SOD、GSH-Px活性均显著升高（P<0.05），MDA含量显著下降（P<0.05），CS、ICD、α-KGDHC和RCCⅠ~Ⅳ活性均显著升高（P<0.01）。结论：有氧运动可以提高老年大鼠骨骼肌线粒体抗氧化能力，降低脂质过氧化水平，提高三羧酸循环及呼吸链功能，促进线粒体能量代谢，延缓衰老过程中线粒体的退行性变化。

Effect of aerobic exercise on energy metabolism of skeletal muscle mitochondria in aging rats

Objective: To investigate the effect of aerobic exercise on energy metabolism of skeletal muscle mitochondria in aging rats.Methods: Twenty female Wistar rats aging to 12-month old were randomly divided into two groups:aged control group (AC,n=10)and aged exercise group (AE,n=10), and another 10 female Wistar rats aging to 2-month old were set as the young control group(YC,n=10). The rats in YC and AC groups were reared normally, the rats in AE group were given treadmill exercise 6 days a week for 12 weeks (slope 5°, speed 15.2 m/min, 15 min on the 1st day, 30 min on the 2nd day, 45 min on the 3th day and beyond). After 12 weeks, all the rats were decapitated, the gastrocnemius samples were taken, the mitochondria were extracted by differential centrifugation and used for measuring the activities of superoxide dismutase(SOD), glutathione peroxidase(GSH-Px), tricarboxylic acid cycling rate-limiting enzymes citrate synthase(CS), isocitrate dehydrogenase(ICD) and α-ketoglutarate dehydrogenase(α-KGDHC), respiratory chain complexs(RCC)Ⅰ~Ⅳ and the content of malondialdehyde(MDA).Results: ①Compared with YC group, the SOD activity and the MDA content were significantly increased (P<0.05),the activities of CS and α-KGDHC were significantly decreased (P<0.05),the activities of RCCⅠ, RCCⅡ and RCC Ⅳ were significantly decreased (P<0.05), and the activity of RCCⅢ was significantly increased (P<0.05) in skeletal muscle mitochondria of AC group; the activities of SOD and GSH-Px and the MDA content were significantly increased (P<0.01), the activities of CS, ICD and α-KGDHC were significantly increased (P<0.01), the activities of RCCⅠ~Ⅳ were significantly increased (P<0.01) in skeletal muscle mitochondria of AE group.②Compared with AC group, the activities of SOD and GSH-Px were significantly increased (P<0.05), MDA content was significantly decreased (P<0.05), the activities of CS, ICD, α-KGDHC and RCCⅠ~Ⅳwere significantly increased (P<0.01) in AE group.Conclusion: Aerobic exercise can improve the antioxidant capacity of skeletal muscle mitochondria in aging rats, decrease the level of lipid peroxidation, improve the function of tricarboxylic acid cycle and respiratory chain, promote mitochondrial energy metabolism, and slow down the degenerative changes in mitochondria during aging.