有氧运动训练后大鼠横纹肌线粒体DNA含量观察

有氧运动训练能使肌肉组织产生适应性变化.从而提高运动耐力.本研究通过不同运动训练方案(无负重游泳3天.60分/天;7天,60分/天;12天,60分/天)、训练及注射钙鳌合剂(EGTA)、氧化剂(GSSG),观察大鼠骨骼肌、心肌线粒体DNA含量的变化规律.结果发现,运动训练3天后,骨骼肌线粒体DNA即表现为增加(57%),7天后降为42%.12天后即不再增加,而此时注射GSSG的训练大鼠线粒体DNA仍增加了26%;心肌线粒体DNA只有在训练12天并注射了GSSG才表现为增加(30%),说明改变细胞内的氧化应激的平衡(有氧运动训练及注射GSSC)可以影响线粒体DNA的生物合成.注射EGTA并训练的大鼠,骨骼肌线粒体则表现为没有显著变化,而在心肌线粒体7天和12天后出现了DNA合成的抑制(-30%,-32%),说明细胞内外的钙平衡也会影响线粒体DNA的生物合成.

An Investigation on the DNA Content of Striated Muscle Mitochondria after Aerobic Exercise Training in Rat

Flow cytometry analysis of propidium iodide (PI)and fluo-3-AM staining were used. The different exercise load of rats (no load swimming 3 days,60 min/day; 7days,60min/days;12days,60min/day.Swimming exogenous GSSG. Swimming exogenous EGTA)showed the different changes of the mitochondria DNA content of skeletal muscle. The results indicated that DNA content in skeletal muscle mitochondria were increased (57%)after 3 days training,there were increased 42% after 7 days training;no changes after 12 days training, but there were still an increase in rat with injection of GSSG after 12 days training (26%). The DNA content of myocardial mitochondria only increased after 12 days training injection of GSSG (30%)and decrease occurred after injecting EGTA 7 days and 12 days training(-30%-32%).These results showed that the redox state (aerobic training and exogenous GSSG)and calcium homeostasis in cell may influence the DNA biosynthesis in striated muscle mitochondria of rat.The results suggested that the redox state in striated muscle mitochondria may be associated with mitochondrial biosynthesis. The increase of the exercise-induced endogenous reactive oxygen species in working muscle mitochondria may lead to the increase of mitochondrial biogenesis during endurance training. The mitochondria in skeletal muscle and myocardium occurred different adaptive changes at the same experimental model.