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。
Effects of different exercise modes on neuromuscular junction and metabolism of skeletal muscle-related proteins in aging rats
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.
skeletal muscleatrophy of musclesneuromuscular junctionexercise
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
展开 >
辽宁师范大学体育学院,大连 116029
齐鲁医药学院,淄博 255300
辽宁师范大学生命科学学院,大连 116029
大连市大连湾中学,大连 116033
闽南理工学院体育学院,泉州 362799
展开 >
骨骼肌 肌肉萎缩 神经肌肉接头 运动
Scientific Research Project from the Education Department of Liaoning Province,ChinaHighend Scientific Research Achievement Cultivation Project of Liaoning Normal University
NETL
NSTL
万方数据
