急性递增负荷运动对骨骼肌自噬系统相关基因表达的影响

Effect of Acute Incremental Load Exercise on Autophagy-related Genes Expression in Skeletal Muscle

目的：通过建立急性递增负荷运动的时相性模型,检测骨骼肌细胞自噬启动阶段关键基因Bec-lin1、膜螯合关键基因Atg9、自噬泡延伸阶段关键基因Atg7和微管相关蛋白1轻链3（LC-3）表达的动态变化,探讨自噬发生不同阶段的关键基因在运动中的适应性情况.方法：40只健康雄性ICR小鼠,7～8周龄,体重19～21g,随机分为安静组（Con）、急性递增负荷运动45min（E45）、90min（E90）、120min（E120）和150min（E150）组,各组均8只.小鼠进行适应性跑台运动,坡度0°,速度0.8km/h,持续时间5min,共训练3天.正式运动遵循以下程序：第1级负荷：1km/h,15min;第2级负荷：1.2km/h,15min;第3级负荷：1.4～1.5km/h,各组分别运动到相应时间点.安静组于安静状态、运动组于运动中相应时间点即刻断颈椎处死,迅速取出完整的下肢腓肠肌.实时荧光定量PCR（Real-time PCR）检测骨骼肌Beclin1、Atg9、Atg7、LC-3基因表达水平.结果：（1）骨骼肌Beclin1 mRNA表达在递增负荷运动开始即急剧上升,在45min达到峰值,随后又呈现持续下降态势.（2）骨骼肌Atg9、Atg7 mRNA表达在递增负荷运动开始即稳步上升,在90min达到峰值,并维持一段时间,随后又呈现稳步下降态势.（3）骨骼肌LC-3 mRNA表达与安静组相比以及各组间相比均未见显著性差异.结论：自噬对递增负荷运动具有较好的应答能力,但这并不总是持续不变的,随着运动时间的延长,其应答能力逐渐降低,表现出一种良好的应激-适应的反应机制.

This paper aimed to set up different phase models of acute incremental load exercise, and investigated the continuous changes of Beclinl, Atg9, Atg7 and LC-3 mRNA transcription in skeletal muscle with quantitative real--time PCR. The purpose was to know whether or not they could adapt to the incremental load exercise. 40 male ICR mice（7-8 weeks old, weight 19-21g） were randomly divided into control group （Con）, acute incremental load exercise for 45min group （E45）, 90min group （E90）, 120min group （El20） and 150min group （E150）, with 8 mice in each group. Three days adaptive treadmill training was finished before formal treadmill exercise （0% grade, 0. 8km/h, 5min）. Quantitative real-time PCR was used to detect the skeletal muscle Beclinl, Atg9, Atg7 as well as LC-- 3 mRNA gene expressions in each group. It was seen that the skeletal muscle Beclinl mRNA gene expression began to rise in the early stage of acute incremental load exercise and increased significantly at 45 min, and then it began to drop quickly. The skeletal muscle Atg9 and Atg7 mRNA gene expressions began to rise in the early stage of acute in- cremental load exercise and increased significantly at 90 min, after maintaining which for a few minutes, they began to drop quickly. The skeletal muscle LC-3 mRNA gene expression did not change significantly compared with the control group during the different stage of acute incremental load exercise. It could be concluded that autophagy might respond much to the incremental load exercise. However, its response ability gradually decreased with the extension of exercise, showing a mechanism of ＂stress-adaptation＂.