李方晖+肖琳+覃飞+刘承宜

摘要：观察8周中等强度低负荷量训练对老龄雌性大鼠腓肠肌Bax和Bcl-2蛋白水平及去乙酰化酶1(SIRT1)/去乙酰化酶3(SIRT3)轴基因信使核糖核酸(mRNA)表达的影响。16只18月龄雌性SD大鼠随机分为对照组和运动组(各8只)。运动组在跑台上以15 km/h(60%~75%VO2max)进行有氧运动，15 min/d，5 d/周，持续运动8周；对照组自由生活。第8周末运动后24 h宰杀并测定腓肠肌指数、蛋白免疫印迹法测定腓肠肌Bax和Bcl-2蛋白水平；逆转录聚合酶链式反应(RT-PCR)测定SIRT3、SIRT1、锰超氧化物歧化酶(MnSOD)、半胱氨酸蛋白酶-3(Caspase-3)、过氧化物酶体增殖活化受体γ辅助活化因子-1α(PGC-1α)、线粒体转录因子A(TFAM)和核呼吸因子1(NRF1) mRNA水平。结果显示，运动组腓肠肌质量(P<0.05)和腓肠肌指数均显著增加(P<0.01)、Bax蛋白水平显著降低(P<0.05)，Bcl-2蛋白水平和Bcl-2/Bax值显著增加(P<0.05)；运动组SIRT3、SIRT1、PGC-1α、NRF1、TFAM、MnSOD mRNA水平显著增加(P<0.05)，Caspase-3 mRNA水平显著降低(P<0.05)。结果表明：中等强度低负荷训练可延缓老龄雌性大鼠肌细胞凋亡信号的改变；SIRT1/SIRT3轴介导的内稳态机制在中等强度低负荷训练提升老龄大鼠骨骼肌线粒体更新速率及抗氧化酶水平起重要作用。

关键词：运动生物化学；运动训练；骨骼肌；第三类去乙酰化酶；内稳态；老龄大鼠

中图分类号：G804.7文献标志码：A文章编号：1006-7116(2014)04-0140-05

Effects of 8-week medium intensity low load training on proteins Bax and Bcl-2 and the gene expression of signal axis SIRT1/SIRT3 of skeletal muscle of

aged female rats

LI Fang-hui1，XIAO Lin1，QING Fei2，LIU Cheng-yi2

（1.School of Physical Education and Health，Zhaoqing University，Zhaoqing 526061，China；

2.Laboratory of Laser Sports Medicine，South China Normal University，Guangzhou 510006，China)

Abstract: In order to observe the effects of 8-week medium intensity low load training on the levels of proteins Bax and Bcl-2 and the gene messenger RNA (mRNA) expression of axis sirtuin 1 (SIRT1)/sirtuin 3 (SIRT3) of gastrocnemius of aged rats, the authors divided 16 18-month old female SD rats randomly into a control group and an exercise group, each of which contained 8 rats, let the rats in the exercise group do an aerobic exercise on a treadmill for consecutive 8 weeks, at a speed of 15 km/h (with 60%~75%VO2max), 15 minutes a day, 5 days a week, let the rats in the control group live freely, in 24 hours after rat exercising at the end of week 8, killed the rats, measured gastrocnemius index, measured the levels of proteins Bax and Bcl-2 of gastrocnemius by means of Western blot analysis, measured the mRNA levels of SIRT3, SIRT1, manganese superoxide dismutase (MnSOD), Caspase 3, peroxisome proliferator-activated receptor-γ coactivator-1 (PGC-1α), mitochondrial transcription factor A (TFAM) and nuclear respiratory factor 1 (NRF1) by means of RT-PCR, and revealed the following findings: as for the rats in the exercise group, their gastrocnemius mass and gastrocnemius index increased significantly (P<0.05 and P<0.01 respectively), their protein Bax level decreased significantly (P<0.05), their protein Bcl-2 level and Bcl-2/Bax ratio increased significantly (P<0.05); their mRNA levels of SIRT3, SIRT1, PGC-1α, NRF1, TFAM and MnSOD increased significantly (P<0.05), their mRNA level of Caspase-3 decreased significantly (P<0.05). The said findings indicated the followings: medium intensity low load training could delay the changing of muscle cell apoptosis signal of aged rats; the homeostatic mechanism mediated by axis SIRT1/SIRT3 played an important role in medium intensity low load training increasing the mitochondria refreshing rate and antioxidase level of skeletal muscle of aged rats.

endprint

Key words: sports biochemistry；sports training；skeletal muscle；type 3 sirtuins；homeostasis；aged rat

肌肉衰减综合症(Sarcopenia)作为一种以骨骼肌质量和肌力衰减为主要特征的增龄性机能退化征，长期以来为人们所忽视[1]。Sarcopenia引发的骨质减少、运动平衡能力下降将增加肢体残疾、心血管病变、心理疾病等发生几率[2]。流行病学调查显示，近13%的60岁以上的老年人受Sarcopenia困扰，该比例在80岁以上老人高达50%[3]。肌细胞凋亡被认为在Sarcopenia发展进程中起关键作用[1，4]。弱化肌细胞凋亡信号、阻止肌细胞大范围地进入凋亡程序是延缓Sarcopenia发生重要机制[4]。文献报道，体力活动不足是Sarcopenia诱因之一，而运动能延缓骨骼肌衰老[5]，这与体育活动能抑制衰老骨骼肌凋亡有关[6]。Song等[6]研究发现，中等强度大负荷量运动后老龄大鼠腓肠肌凋亡显著减少。……