5周间歇性亚极限强度运动中大鼠睾丸组织StAR及其调控因子的时序性变化

Sequential Changes of StAR Protein and Its Regulatory Factors in Testicular Tissue of Rats during 5-week sub-ultimate Intensity Exercise

目的:探讨5周间歇性亚极限强度运动引起大鼠睾酮水平下降的可能机制。方法:8周龄SD大鼠分为运动干预组和安静对照组,运动组大鼠以尾部负重的方式(6%体重)进行4min×5次游泳训练,间隔90 s,上、下午各进行1次训练,每周6天,分别持续1、2、3、4、5周。各组大鼠末次训练结束48 h后取材,测定StAR、PKA、pCREB、SF-1等相关蛋白及基因mRNA变化情况。结果:1)运动干预组血睾酮水平后2周下降幅度较大,第5周血睾酮水平与安静对照组相比下降了70%(P<0.01)。2)运动干预组大鼠StAR mRNA在第5周出现了显著性下降(P<0.05)。3)大鼠睾丸组织PKA、pCREB、SF-1蛋白表达以及SF-1 mRNA表达在后2周出现了显著下降(P<0.05)。结论:5周间歇性亚极限强度运动引起大鼠睾丸间质细胞内St AR及其相关调控因子PKA、pCREB、SF-1等表达下降,进而引起胆固醇转运受限,这可能是导致睾酮合成和血液睾酮水平下降的原因之一。

Objective：To explore the possible mechanism of 5-week intermittent sub-ultimate intensity exercise induced low serum testosterone in rats. Methods：The rats in the exercise group received weight bearing training sessions. Each session consisted of five 4-minute weight bearing（6% body weight） swimming separated by 90-second intervals. Training sessions were given twice a day and six days a week. The length of experiment was set to be 1,2,3,4 and 5 weeks. 48 hours after the last training session,rats from each groups were sampled in order to analyze protein and gene mRNA changes of StAR,PKA,p CREB,SF-1. Results：1） The serum testosterone level in intervention group decreased at a significant rate in the last two weeks,the serum testosterone level in the fifth group decreased by 70% compared to control group（P 0.01）. 2） The expression of StAR mRNA in the fifth week was significantly different than the control group（P0.05）.3） The expression of PKA,p CREB,SF-1 protein and SF-1 mRNA in testis decreased significantly in the last two weeks.（P0.05）. Conclusion：StAR and its associated regulators PKA,p CREB,SF-1 in testicular leydig cells declined after 5-week intermittent sub-ultimate intensity exercise,thus mitochondrial cholesterol transfer limitation might be one of the mechanisms of decline in testosterone synthesis and serum testosterone.