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目的研究雄性大鼠在模拟微重力下睾丸组织中类固醇激素合成相关基因表达的变化,探讨微重力对睾丸中睾酮合成的影响,以及这种影响与血浆睾酮含量变化的关系。方法建立无隐睾尾部悬吊大鼠的模拟微重力模型;采用酶联免疫竞争(ELISA)法测定大鼠血浆睾酮的含量;逆转录聚合酶链反应(RT-PCR)法检测睾丸组织中类固醇激素合成急性调节蛋白(StAR)、细胞色素P450-17α-羟化酶(P450c17)、3β-羟甾脱氢酶(3β-HSD)的mRNA水平的变化。结果雄性大鼠在模拟微重力条件下7d后,睾丸重量极显著减轻(P<0.01),血浆睾酮含量极显著下降(P<0.01),睾丸组织中StAR、P450c17、3β-HSD的mRNA水平显著下调(P<0.05)。结论模拟微重力引起雄性大鼠睾丸中StAR、P450c17、3β-HSD的表达下调,使睾酮合成途径受阻,导致睾酮分泌减少,进而造成血浆睾酮含量下降。
Objective To investigate the changes of steroid hormone related gene expression in testis tissue under simulated microgravity in male rats and to explore the effect of microgravity on testosterone synthesis in testis and the relationship between the effect of testosterone and plasma testosterone content. Methods The simulated microgravity model of rat with cryptorchidism tail suspension was established. The content of plasma testosterone was determined by enzyme-linked immunosorbent assay (ELISA). The levels of steroid in testis tissue were detected by reverse transcription-polymerase chain reaction (RT-PCR) Changes in mRNA levels of StAR, cytochrome P450-17α-hydroxylase (P450c17), and 3β-hydroxysteroid dehydrogenase (3β-HSD) were investigated. Results The testicular weight was significantly reduced (P <0.01) and the content of plasma testosterone was significantly decreased (P <0.01) in male rats 7 days after simulated microgravity. The mRNA levels of StAR, P450c17 and 3β-HSD in testis were significantly increased Down (P <0.05). Conclusion Simulated microgravity induced the down-regulation of StAR, P450c17 and 3β-HSD in the testis of male rats, which obstructed the testosterone biosynthesis, leading to the decrease of testosterone secretion and the decrease of plasma testosterone.