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不同运动方式对衰老大鼠神经肌肉接头和骨骼肌相关蛋白代谢的影响

苏艳红^1,*, 程翌², 李婷婷¹, 张熠晨¹, 杜泽宇³, 陈娟¹, 王福清¹, 刘忠浩⁴, 龚文翰⁵

¹辽宁师范大学体育学院，大连 116029；²齐鲁医药学院，淄博 25530；³辽宁师范大学生命科学学院，大连 116029；⁴大连市大连湾中学，大连 116033；⁵闽南理工学院体育学院，泉州 362799

摘要

本研究通过对衰老大鼠进行运动训练，探究不同运动方式对神经肌肉接头(neuromuscular junction, NMJ)和骨骼肌相关蛋白代谢的影响及机制。从38只3月龄SPF级Sprague-Dawley (SD)雄性大鼠中随机选出10只作为青年对照组(Y组)，其余养至21月龄后随机分为老年对照组(O组、8只)、耐力运动组(EN组、10只)、抗阻运动组(R组、10只)。经过相对应的8周训练后，取大鼠腓肠肌，用免疫荧光染色法检测S100B在施旺细胞上的表达水平。用Western blot检测凝集蛋白(Agrin)、低密度脂蛋白受体相关蛋白4 (low-density lipoprotein receptor-related protein 4, Lrp4)、肌肉特异性激酶(muscle-specific kinase protein, MuSK)、酪氨酸激酶下游分子7 (downstream of tyrosine kinase 7, Dok7)与磷酸化蛋白激酶B (phosphorylated protein kinase B, p-Akt)、磷酸化哺乳动物雷帕霉素靶蛋白(phosphorylated mammalian target of rapamycin, p-mTOR)、磷酸化叉头转录因子1 (phosphorylated forkhead box O1, p-FoxO1)蛋白表达水平。结果显示，耐力和抗阻运动均提高衰老大鼠腓肠肌湿重比。R组S100B蛋白表达显著高于O组和EN组；与Y组比较，O组大鼠腓肠肌NMJ功能相关蛋白Agrin、Lrp4、MuSK、Dok7蛋白表达水平显著下调；衰老大鼠经过抗阻运动后，腓肠肌Agrin、Lrp4、MuSK、Dok7蛋白表达水平均显著上调，而衰老大鼠经耐力运动后仅Agrin蛋白表达水平显著上调，而Lrp4、MuSK、Dok7蛋白表达未得到改善。在骨骼肌相关蛋白代谢相关通路中，与Y组比较，O组大鼠腓肠肌p-Akt、p-mTOR蛋白表达水平下调，p-FoxO1蛋白表达水平上升；抗阻和耐力运动可逆转衰老大鼠p-mTOR和p-FoxO1蛋白表达的变化。以上结果表明，两种运动方式均可改善衰老大鼠NMJ功能，并增加骨骼肌蛋白质合成，降低骨骼肌蛋白质分解代谢，且抗阻运动效果更加显著。

关键词： 骨骼肌; 肌肉萎缩; 神经肌肉接头; 运动

Effects of different exercise modes on neuromuscular junction and metabolism of skeletal muscle-related proteins in aging rats

SU Yan-Hong^1,*, CHENG Yi², LI Ting-Ting¹, ZHANG Yi-Chen¹, DU Ze-Yu³, CHEN Juan¹, WANG Fu-Qing¹, LIU Zhong-Hao⁴, GONG Wen-Han⁵

¹School of Physical Education, Liaoning Normal University, Dalian 116029, China；²Qilu Medical University, Zibo 255300, China；³School of Life Science, Liaoning Normal University, Dalian 116029, China；⁴Dalian Bay Middle School, Dalian 116033, China；⁵School of Physical Education, Minnan University of Science and Technology, Quanzhou 362799, China

Abstract

The present study aimed to explore the effects of different exercise modes on neuromuscular junction (NMJ) and metabolism of skeletal muscle-related proteins in aging rats. Ten from 38 male Sprague-Dawley (SD) rats (3-month-old) were randomly selected into young (Y) group, while the rest were raised to 21 months old and randomly divided into elderly control (O), endurance exercise (EN) and resistance exercise (R) groups. After 8 weeks of corresponding exercises training, the gastrocnemius muscles of rats were collected, and the expression of S100B in Schwann cells was detected by immunofluorescence staining. Western blot was used to detect the protein expression levels of agglutinate protein (Agrin), low-density lipoprotein receptor-related protein 4 (Lrp4), muscle- specific kinase protein (MuSK), downstream tyrosine kinase 7 (Dok7), phosphorylated protein kinase B (p-Akt), phosphorylated mammalian target rapamycin (p-mTOR), and phosphorylated forkhead box O1 (p-FoxO1) in rat gastrocnemius muscles. The results showed that, endurance and resistance exercises increased the wet weight ratio of gastrocnemius muscle in the aging rats. The protein expression of S100B in the R group was significantly higher than those in the O and EN groups. Proteins related to NMJ function, including Agrin, Lrp4, MuSK, and Dok7 were significantly decreased in the O group compared with those in the Y group. Resistance exercise up-regulated these four proteins in the aging rats, whereas endurance exercise could not reverse the protein expression levels of Lrp4, MuSK and Dok7. Regarding skeletal muscle-related proteins, the O group showed down-regulated p-Akt, and p-mTOR protein expression levels and up-regulated p-FoxO1 protein expression level, compared to the Y group. Resistance and endurance exercises reversed the changes in p-mTOR and p-FoxO1 protein expression in the aging rats. These findings demonstrate that both exercise modes can enhance NMJ function, increase protein synthesis and reduce the catabolism of skeletal muscle-related proteins in aging rats, with resistance exercise showing a more pronounced effect.

Key words: Skeletal muscle; atrophy of muscles; neuromuscular junction; exercise

收稿日期：　　录用日期：

通讯作者：苏艳红　　E-mail:

DOI: 10.13294/j.aps.2024.0039

引用本文：

苏艳红, 程翌, 李婷婷, 张熠晨, 杜泽宇, 陈娟, 王福清, 刘忠浩, 龚文翰. 不同运动方式对衰老大鼠神经肌肉接头和骨骼肌相关蛋白代谢的影响[J]. 生理学报 2024; 76 (3): 376-384.

SU Yan-Hong, CHENG Yi, LI Ting-Ting, ZHANG Yi-Chen, DU Ze-Yu, CHEN Juan, WANG Fu-Qing, LIU Zhong-Hao, GONG Wen-Han. Effects of different exercise modes on neuromuscular junction and metabolism of skeletal muscle-related proteins in aging rats. Acta Physiol Sin 2024; 76 (3): 376-384 (in Chinese with English abstract).