低氧暴露对大鼠急性离心运动后Dystrophin表达的影响

发布时间：2018-06-09 13:56

本文选题：离心运动 + 低氧　；参考：《北京体育大学》2016年博士论文

【摘要】：目的：观察急性离心运动后大鼠腓肠肌Dystrophin表达及相应信号通路变化,并验证低氧是否通过此信号通路调控Dystrophin表达,为高住低训提供理论依据。方法：研究一：70只雄性SD大鼠分安静对照组、常氧运动后常氧恢复24H、48H、72H组和常氧运动后低氧暴露24H、48H、72H组。运动组大鼠进行一次间歇性离心运动后,于不同环境下恢复。研究二：72只雄性SD大鼠分为安静对照组、ERK1/2抑制剂24H、48H组；ERK1／2安慰剂24H、48H组；AKT抑制剂24H、48H组和AKT安慰剂24H、48H组。除安静对照组外,其他组在运动后进行低氧暴露。采用免疫组化、Western blot、qRT-PCR等方法检测大鼠腓肠肌细胞膜完整性、Dystrophin mRNA及蛋白表达、ERK1/2和AKT/mTOR通路的蛋白表达。结果：(1)离心运动后低氧暴露,大鼠腓肠肌阳性细胞率在各时间点与常氧恢复组比较,呈现显著性上升、下降再上升的趋势。(2)急性离心运动后,Dystrophin蛋白含量在各组中未出现显著性变化；Dystrophin mRNA表达水平显著性降低,且低氧暴露组mRNA水平低于常氧恢复组；ERK和AKT/mTOR通路蛋白及磷酸化水平存在时相性差异,低氧暴露组ERK通路蛋白及磷酸化水平变化趋势与Dystrophin mRNA表达一致。(3)注射MEK靶向抑制剂可在运动后48h阻断ERK通路蛋白及磷酸化水平,抵消低氧通过ERK1/2信号传导途径调控Dystrophin mRNA的作用。而AKT靶向抑制剂在运动后24h即已抑制了AKT的表达,但对Dystrophin没有显著影响。结论：(1)离心运动后急性低氧暴露可加剧骨骼肌细胞膜损伤。随着低氧暴露时间的延长,机体产生了短暂适应,细胞膜完整性得到一定恢复。(2)急性离心运动后24h-72h, Dystrophin蛋白表达无明显变化,基因含量显著下降。(3)低氧可通过ERK1/2信号通路调控Dystrophin mRNA表达,进而调节Dystrophin蛋白表达。ERK1/2信号通路与Dystrophin mRNA间存在负向调节作用。(4)AKT/mTOR信号传导通路在低氧对Dystrophin蛋白表达影响中并不占据主导调控地位。
[Abstract]:Aim: to observe the changes of dystrophin expression and signal pathway in gastrocnemius muscle after acute centrifugation, and to verify whether hypoxia regulates the expression of dystrophin through this signaling pathway, which provides a theoretical basis for high living and low training. Methods: a total of 70 male Sprague-Dawley rats were divided into two groups: the control group, the normal oxygen recovery group after normoxic exercise, and the control group, which were exposed to hypoxia after normoxic exercise. The rats in the exercise group recovered in different environments after an intermittent eccentric exercise. In this study, 72 male Sprague-Dawley rats were divided into two groups: the quiet control group with ERK1 / 2 inhibitor 24H, the control group with ERK1 / 2 placebo 24H4H 48H and the AKT placebo with 24Hn48H and the AKT placebo 24H with 48H. In addition to quiet control group, other groups were exposed to hypoxia after exercise. The expression of dystrophin mRNA and protein in rat gastrocnemius muscle cell membrane was detected by Western blottit qRT-PCR, and the protein expression of ERK1 / 2 and AKT / mTOR pathway was detected. Results (1) compared with normoxic recovery group, the positive cell rate of gastrocnemius muscle increased significantly in rats exposed to hypoxia after centrifugation. There was no significant change in Dystrophin protein content after acute centrifugation. There was no significant change in Dystrophin mRNA expression in each group. The mRNA levels in hypoxia group were lower than those in normoxic recovery group, and the protein and phosphorylation levels of ERK and AKT / mTOR pathway were significantly lower than those of normoxic recovery group. The changes of ERK pathway protein and phosphorylation level in hypoxic exposure group were consistent with the expression of dystrophin mRNA. (3) injection of MEK targeting inhibitor could block ERK pathway protein and phosphorylation at 48 h after exercise, and counteract the effect of hypoxia on regulating Dystrophin mRNA through ERK1 / 2 signal transduction pathway. AKT-targeted inhibitors inhibited AKT expression 24 hours after exercise, but had no significant effect on dystrophin. Conclusion (1) Acute hypoxic exposure after eccentric exercise can aggravate the damage of skeletal muscle cell membrane. With the prolongation of hypoxic exposure time, the body had a transient adaptation, cell membrane integrity was recovered to some extent.) after 24 h-72 h of acute centrifugation, the expression of dystrophin protein did not change significantly. Hypoxia can regulate the expression of dystrophin mRNA through ERK1 / 2 signaling pathway. Furthermore, the regulation of Dystrophin protein expression. ERK1 / 2 signaling pathway and Dystrophin mRNA has negative regulatory effect. The AKT / mTOR signal transduction pathway does not play a dominant role in the effect of hypoxia on dystrophin protein expression.
【学位授予单位】：北京体育大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：G804.2

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