【作者】 王永梅；

【导师】 李世昌；

【作者基本信息】 华东师范大学 ， 体育人文社会学， 2010， 硕士

【摘要】 研究目的：本研究建立模拟失重模型——后肢悬吊,以期研究后肢悬吊引起骨骼肌萎缩现象的发生及其分子机理；同时建立耐力训练模型,探讨运动引起MyoD、myogenin、MEF2mRNA的变化在抗肌萎缩中的作用。研究方法：本研究采用四周龄健康雄性SD大鼠28只,平均体重为134.02g,随机分为对照组(C,n=7)、跑台组(E,n=7)、失重组(U,n=7)和跑台失重组(EU,n=7)。跑台组前3天在跑步机上先进行适应性训练,每天半小时；以后跑步机按20m/min、坡度为5°设定,每天训练一个小时。每周训练六天,周末休息,共训练8周。实验过程中,每周称体重一次。失重组前8周不做任何特殊处理,第9、10周悬吊。跑台失重组前8周按跑台组的方案进行训练,第9、10周悬吊。8周跑台训练后取血液检测血乳酸：跑台组和对照组大鼠处死,取腓肠肌以备测试。悬吊2周后,跑台失重组和失重组处死,取大鼠腓肠肌,用HE染色测试横截面积,用RT-PCR方法测试腓肠肌MEF2mRNA、MyoDmRNA和myogeninmRNA表达水平。研究结果：1、与对照组相比,跑台组体重下降,两组大鼠体重有极显著性差异(P<0.01)。2、大鼠后肢悬吊2周后,与失重组相比,跑台失重组大鼠体重稍微增加,而跑台失重组大鼠腓肠肌湿重和横截面积下降的幅度均小于失重组大鼠腓肠肌湿重和横截面积下降的幅度,且有显著性差异(P<0.05)3、跑台训练8周后,与对照组相比,跑台组的MEF2mRNA、MyoD和myogeninmRNA表达量都有所上升,且有显著性差异(P<0.05)结论：1、与对照组比较,失重组和跑台失重组两组的大鼠体重、腓肠肌湿重和横截面积均有显著的下降,说明后肢悬吊可以引起大鼠体重、骨骼肌重量和横截面积的减少,提示本实验中后肢悬吊失重模型的建立是成功的。2、与失重组相比,跑台失重组的大鼠悬吊前后腓肠肌湿重和横截面积下降的幅度较小,说明跑台运动对预防失重后肌萎缩有一定效果。3、8周的跑台训练后,与对照组相比,跑台组大鼠腓肠肌的MyoD、yogenin和MEF2mRNA表达量均有所上升,且有显著性差异(P<0.05)。大鼠后肢悬吊两周前后,失重组和跑台失重组两组的MyoD、myogenin和MEF2mRNA表达量变化也有差别,跑台失重组悬吊前后MyoD、myogenin和MEF2mRNA表达量下降的幅度,小于失重组MyoD、myogenin和MEF2mRNA表达量下降的幅度,有显著性差异(P<0.05)。而且MyoD和MEF2mRNA表达趋势相似,说明这两个因子MyoD、MEF2在对抗肌萎缩机制中起正协同作用。这三个因子在失重前后表达量的变化也说明它们可以作为研究肌萎缩的分子生物学指标。更多还原

【Abstract】 Objects:The model of weightlessness was simulated in this study-hindlimb suspension in order to study the phenomenon of skeletal muscle atrophy caused by hindlimb suspension and molecular mechanism of the occurrence; while establishing endurance training model of exercise-induced MyoD, myogenin, MEF2mRNA change in the role of dystrophin.Methods:The experiment use 28 4-week-old male Sprague-Dawley rats, weighing134.02g.They were randomly divided into 4 groups, control group (C, n=7); treadmill group (E group, n =7); suspension group (U, n=7); treadmill suspension group (EU, n=7). Treadmill Group: the first 3 days, adaptive training, half an hour a day, and then 1.2KM/h, gradient of 5 Every Monday to Saturday, a total of six days, an hour a day, breaks at weekend, trained a total of 8 weeks. Weighed once every week. suspension group:without any special treatment for 8 weeks, suspension for the 9,10-week.Treadmill suspension group: programmed by treadmill training group, then suspension for the 9,10-week.After 8-week treadmill training, taking blood tests of blood lactic acid; suspended after 2 weeks, HE for measuring cross-sectional area, Using RT-PCR method for measuring expression of MEF2mRNA, MyoD, myogeninmRNA.Results:1. Compared with the control group, the body weight of treadmill group reduced, there was significant difference in body weight of two groups of rats (P<0.05).2. Hindlimb suspended for 2 weeks, compared with the suspension group, the decrease margin of gastrocnemius muscle wet weight and cross sectional area of treadmill suspension group is smaller than that in suspension group, and there was significant difference (P<0.05).3. After 8 weeks of treadmill training, compared with the control group, the expression of MEF2mRNA, MyoD and myogeninmRNA have risen, and there was significant difference (P<0.05). Conclusions:1. Compared with the control group, the weight, gastrocnemius muscle wet weight and cross-sectional area decrease significantly, indicating hindlimb suspension can cause reduction in body weight, muscle weight and cross-sectional area, suggesting that the model of hindlimb suspension is successful.2. Compared with the suspension group, body weight of treadmill suspension group increases slightly,but the decrease margin of gastrocnemius muscle wet weight and cross sectional area of treadmill suspension group is smaller, indicating treadmill exercise on prevention of muscle atrophy after suspension has some effect.3. After 8 weeks treadmill training, compared with the control group, the expression of gastrocnemius MyoD, myogenin and MEF2mRNA increase, and there was significant difference (P<0.05). After two weeks of hindlimb suspension, the changes of expression of MyoD, myogenin and MEF2mRNA of two groups have also a big difference, the change of expression of MyoD, myogenin and MEF2mRNA of treadmill suspension group is less than suspension group, there was significant difference (P<0.05). And the trend of expression of MyoD and MEF2mRNA is similar, indicating the mechanism of these two factors in the fight against muscle atrophy is coordinated. The change of expression of these three factors before and after suspension also shows that they can be used as the molecular biology of muscle atrophy.更多还原