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高频电刺激小鼠坐骨神经促进骨骼肌自噬

杨映娟, Jeffrey E. Pessin, 王兰

山西大学生命科学学院，太原 030006；爱因斯坦医学院医学与分子药理学系，纽约 10461，美国

摘要

本研究旨在探讨运动对骨骼肌自噬的调控作用。以小鼠为研究对象，通过高频(100 Hz)电刺激单侧坐骨神经的方法使同侧骨骼肌收缩，以对侧肌肉作为未刺激对照组。分别收集电刺激完成后0、30和60 min的腓肠肌肌肉组织，迅速投入液氮冷冻备用。采用实时荧光定量PCR和Western blot检测自噬相关基因mRNA与蛋白的表达水平。研究结果显示，在电刺激完成后0 min，相比对侧未刺激骨骼肌，电刺激一侧的骨骼肌腺苷酸活化蛋白激酶(AMP-activated protein kinase, AMPK)活性升高，自噬标志蛋白LC3-II/I比率显著升高，蛋白酶体泛素连接酶基因(atrogin-1和MuRF-1)和自噬相关基因(CathepsinL、Bnip3和Bnip3l) mRNA表达均显著上调，自噬相关蛋白ULK1活性升高。上述结果提示，电刺激引起的骨骼肌收缩可促进骨骼肌自噬水平升高，该过程可能通过AMPK/ULK1介导的信号途径调控。

关键词： 电刺激; 骨骼肌 ; 衰老 ; 自噬 ; LC3

分类号：R329

High frequency electrical stimulation of sciatic nerve enhances skeletal muscle autophagy in mice

YANG Ying-Juan, Jeffrey E. Pessin, WANG Lan

School of Life Sciences, Shanxi University, Taiyuan 030006, China； Department of Medicine and Molecular Pharmacology, Albert Einstein College of Medicine, NY 10461, USA

Abstract

The aim of the present study was to investigate the effects of exercise on skeletal muscle autophagy. Trains of high-frequency electrical stimulation (pulses frequency: 100 Hz) were used to stimulate sciatic nerve and consequently induce muscle contraction of the left hindlimb. The unstimulated right hindlimb muscles were taken as control. The mice were sacrificed immediately (0), 30 or 60 min after the electrical stimulation by cervical dislocation, and gastrocnemius muscles were rapidly dissected and freeze-clamped in liquid nitrogen. AMP-activated protein kinase (AMPK) and the autophagy marker protein LC3 were detected by Western blotting, and muscle atrophy related genes including atrogin-1, MuRF-1, Bnip3, Bnip3l and CathepsinL were detected by using real-time qPCR. The results showed that, at 0 min after the electrical stimulation, the activity of AMPK and LC3-II/I ratio were significantly increased in left gastrocnemius muscles, compared with those of the muscles in the right hindlimb. The levels of atrogin-1, MuRF-1, Bnip3, Bnip3l and CathepsinL mRNA expressions were up-regulated by electrical stimulation. Meanwhile, the activity of autophagy related protein, ULK1 was significantly enhanced by electrical stimulation. These results suggest that electrical stimulation of sciatic nerve may induce the skeletal muscle autophagy, and this may be regulated through AMPK/ULK1-mediated signaling pathway.

Key words: Electrical stimulation; skeletal muscle ; aging ; autophagy ; LC3

收稿日期：2016-12-29　　录用日期：2017-03-14

通讯作者：王兰　　E-mail: lanwang@sxu.edu.cn

引用本文：

杨映娟, Jeffrey E. Pessin, 王兰. 高频电刺激小鼠坐骨神经促进骨骼肌自噬[J]. 生理学报 2017; 69 (4): 422-428.

YANG Ying-Juan, Jeffrey E. Pessin, WANG Lan. High frequency electrical stimulation of sciatic nerve enhances skeletal muscle autophagy in mice. Acta Physiol Sin 2017; 69 (4): 422-428 (in Chinese with English abstract).