雄激素经IGF-I介导调节运动骨骼肌mTOR信号机理的探索
发布时间：2018-09-11 10:14
【摘要】：研究目的：本研究通过不同强度运动及应用IGF-I和雄激素,观察运动骨骼肌AR、MAPK和mTOR通路间的变化特点与规律,对雄激素经IGF-I介导调节运动骨骼肌mTOR信号机理进行探讨。 研究方法：实验一雄性SD大鼠进行不同强度运动(跑台运动：速度20min/min和26m/min、60min、10%坡度),运动后即刻、6h和12h取材白腓肠肌。实验二雄性SD大鼠肌肉注射IGF-I,注射后20、60和120min取白腓肠肌。实验三将雄性SD大鼠分为安静对照组(S)、DHT组(D)、运动组(E)和DHT运动组(ED),D和ED组颈背部皮下埋植DHT缓释剂,其余假手术。E和ED组进行以20m/min、60min、10%坡度的跑台运动。再细分为三天组和十天组,运动后12h取白腓肠肌。BCA法测肌肉蛋白浓度,HE染色观察骨骼肌形态,实时荧光定量RT-PCR测肌肉AR和IGF-I基因表达,Western Blot法测肌肉MHC和AR、MEK、ERK、p90RSK、 mTOR、p70S6K和4EBP1的磷酸化。 研究结果：(1)急性运动时,骨骼肌AR、MAPK和mTOR通路磷酸化状态存在运动强度依赖性,且MAPK通路活性在运动后即刻出现峰值,AR和mTOR通路的出现于6小时。(2)肌肉注射外源性IGF-I增强了肌肉AR表达,AR活性于注射后60min达峰值。骨骼肌MAPK和mTOR通路活性增强,均于注射后20min达到峰值。(3)皮下埋植DHT使肌肉横断面、湿重和MHC明显增加。运动加强了雄激素的促合成效应。(4)DHT作用三天明显增加肌肉内IGF-I含量,而DHT结合运动后能进一步提高肌肉内IGF-I。(5)皮下埋植DHT使MAPK和mTOR通路的表达均显著增强。 研究结论：(1)骨骼肌AR、MAPK通路和mTOR通路的活性存在强度依赖性。急性运动后骨骼肌MAPK通路峰值出现较早,AR和mTOR通路峰值较晚。(2)雄激素明显促进了骨骼肌的肥大,还增强了肌肉IGF-I生成。运动能加强了雄激素的促肌肉合成效应。同时,IGF-I除促进骨骼肌AR的表达及其活性外,还能迅速促进MAPK通路和mTOR通路的活性。(3)骨骼肌MAPK通路和mTOR通路均为雄激素的非基因途径,且MAPK通路位于mTOR通路的上游。
[Abstract]:Objective: to observe the changes of AR,MAPK and mTOR pathway in skeletal muscle by using IGF-I and androgen at different intensities, and to explore the mechanism of mTOR signal regulation by IGF-I mediated by androgen. Methods: male SD rats underwent different intensity exercises (treadmill movement: speed 20min/min and 26 m / min 60 min / min 10% slope). The white gastrocnemius muscle was obtained immediately after exercise for 6 h and 12 h. In experiment 2, the white gastrocnemius muscle was taken from male SD rats by intramuscular injection of IGF-I, (20: 60 and 120min). In experiment 3, male SD rats were divided into control group, (D), group, (E) group, DHT exercise group, (ED) D group and ED group, where DHT was implanted subcutaneously into the neck and back. The rest of sham-operated .E and ED groups were treated with 10% slope treadmill exercise at 20 m / min for 60 min. After 12 hours exercise, the muscle protein concentration was measured by HE staining, and the expression of AR and IGF-I genes in muscle was measured by real-time fluorescence quantitative RT-PCR. The phosphorylation of MHC, AR,MEK,ERK,p90RSK, mTOR,p70S6K and 4EBP1 in muscle was detected by Western Blot. Results: (1) Phosphorylation of AR,MAPK and mTOR pathways in skeletal muscle was intensity-dependent during acute exercise. The activity of MAPK pathway appeared peak at 6 hours after exercise. (2) exogenous IGF-I increased the activity of AR expression in muscle and reached the peak value of 60min after injection. The MAPK and mTOR pathway activity of skeletal muscle increased, both of which reached the peak value after injection. (3) Subcutaneous implantation of DHT significantly increased muscle cross-section, wet weight and MHC. Exercise enhanced the effect of androgen synthesis. (4) DHT significantly increased the content of IGF-I in muscle for three days, while DHT combined with exercise could further increase the expression of MAPK and mTOR pathway after subcutaneous implantation of DHT (5) in muscle. Conclusion: (1) the activities of AR,MAPK pathway and mTOR pathway in skeletal muscle are intensity-dependent. The peak value of MAPK pathway in skeletal muscle after acute exercise was earlier than that in AR and mTOR pathway. (2) androgen significantly promoted skeletal muscle hypertrophy and increased muscle IGF-I production. Exercise boosts the effect of androgen on muscle synthesis. At the same time, IGF-I not only promoted the expression and activity of AR in skeletal muscle, but also increased the activity of MAPK pathway and mTOR pathway. (3) the MAPK pathway and mTOR pathway of skeletal muscle were both non-androgen pathways, and MAPK pathway was located upstream of mTOR pathway.
【学位授予单位】：北京体育大学
【学位级别】：博士
【学位授予年份】：2012
【分类号】：G804.2
本文编号：2236396
[Abstract]:Objective: to observe the changes of AR,MAPK and mTOR pathway in skeletal muscle by using IGF-I and androgen at different intensities, and to explore the mechanism of mTOR signal regulation by IGF-I mediated by androgen. Methods: male SD rats underwent different intensity exercises (treadmill movement: speed 20min/min and 26 m / min 60 min / min 10% slope). The white gastrocnemius muscle was obtained immediately after exercise for 6 h and 12 h. In experiment 2, the white gastrocnemius muscle was taken from male SD rats by intramuscular injection of IGF-I, (20: 60 and 120min). In experiment 3, male SD rats were divided into control group, (D), group, (E) group, DHT exercise group, (ED) D group and ED group, where DHT was implanted subcutaneously into the neck and back. The rest of sham-operated .E and ED groups were treated with 10% slope treadmill exercise at 20 m / min for 60 min. After 12 hours exercise, the muscle protein concentration was measured by HE staining, and the expression of AR and IGF-I genes in muscle was measured by real-time fluorescence quantitative RT-PCR. The phosphorylation of MHC, AR,MEK,ERK,p90RSK, mTOR,p70S6K and 4EBP1 in muscle was detected by Western Blot. Results: (1) Phosphorylation of AR,MAPK and mTOR pathways in skeletal muscle was intensity-dependent during acute exercise. The activity of MAPK pathway appeared peak at 6 hours after exercise. (2) exogenous IGF-I increased the activity of AR expression in muscle and reached the peak value of 60min after injection. The MAPK and mTOR pathway activity of skeletal muscle increased, both of which reached the peak value after injection. (3) Subcutaneous implantation of DHT significantly increased muscle cross-section, wet weight and MHC. Exercise enhanced the effect of androgen synthesis. (4) DHT significantly increased the content of IGF-I in muscle for three days, while DHT combined with exercise could further increase the expression of MAPK and mTOR pathway after subcutaneous implantation of DHT (5) in muscle. Conclusion: (1) the activities of AR,MAPK pathway and mTOR pathway in skeletal muscle are intensity-dependent. The peak value of MAPK pathway in skeletal muscle after acute exercise was earlier than that in AR and mTOR pathway. (2) androgen significantly promoted skeletal muscle hypertrophy and increased muscle IGF-I production. Exercise boosts the effect of androgen on muscle synthesis. At the same time, IGF-I not only promoted the expression and activity of AR in skeletal muscle, but also increased the activity of MAPK pathway and mTOR pathway. (3) the MAPK pathway and mTOR pathway of skeletal muscle were both non-androgen pathways, and MAPK pathway was located upstream of mTOR pathway.
【学位授予单位】：北京体育大学
【学位级别】：博士
【学位授予年份】：2012
【分类号】：G804.2
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