耐力运动8周对大鼠骨骼肌收缩功能和线粒体生物合成的影响及机制

摘要

Aim This study was aimed to explore the influence and mechanism of the long-term exercise on skeletal muscle contraction and mitochondrial biosyn-thesis in different muscle fibers.Methods Soleus (SOL)and extensor digitorum longus (EDL)were i-solated from SD male rats with platform running train-ing for eight weeks.The changes of contractility under different electrical stimulation were observed, mito-chondrial biosynthesis,including ATP content,mito-chondrial DNA,the gene expression of PGC-1αand NRF were also detected.Results Long-term endur-ance exercise can improve twitch tension and titanic tension of SOL and EDL ,but only enhanced the fa-tigue resistance in SOL.ATP contents were significant-ly increased in the two types of muscles,but mtDNA content,PGC-1αexpression and NRF translation were only obviously enhanced in SOL,in accompanied with an increase in p-AMPK/AMPK protein ratio.Conclu-sion Long-term endurance exercise increased skeletal muscle contractility and improved the anti-fatigue abili-ty in SOL,which may be associated with increase in mitochondrial biosynthesis via activated AMPK-PGC-1αaxis.%目的：探讨8周耐力运动对不同类型骨骼肌收缩功能及线粒体能量代谢能力的影响及其机制。方法分离经8周平台跑步训练的♂ SD大鼠的比目鱼肌和趾长伸肌，观测给予不同方式电刺激后两种类型骨骼肌收缩能力和抗疲劳能力的变化以及ATP含量和线粒体生物合成相关指标的改变。结果耐力运动8周可一定程度提高比目鱼肌和趾长伸肌在单次电刺激和强直电刺激下的收缩力，明显改善比目鱼肌的抗疲劳能力。ATP含量在两类肌肉中均明显升高，但只有比目鱼肌线粒体 DNA、PGC-1α、NRF 基因的转录及PGC-1α蛋白明显上调，并伴随p-AMPK／AMPK蛋白比值明显增加。结论耐力运动8周改善骨骼肌的收缩能力，但仅增加富含氧化型肌纤维的比目鱼肌的抗疲劳能力，这可能与耐力运动激活氧化型肌纤维的AMPK，上调PGC-1α转录和表达，增加线粒体生物合成有关。