镉对小鼠睾丸间质细胞睾酮合成的影响

目的 探讨镉对小鼠睾丸间质细胞睾酮合成的影响.方法 镉处理组采用20 μmol/L CdCl2处理TM3细胞,分别在加入CdCl2 4 h和8 h后收集细胞上清液,对照组TM3细胞给予等容积磷酸盐缓冲液(DPBS).采用ELISA法测定细胞上清液中睾酮含量,采用RT-PCR和Western blot技术检测睾酮合成关键酶mRNA和蛋白表达水平.结果 镉处理组细胞上清液中睾酮含量明显降低(P＜0. 01).与对照组相比,镉显著下调TM3细胞类固醇激素合成急性调控蛋白(StAR)、细胞色素P450胆固醇侧链裂解酶(P450scc)与 17β-羟类固醇脱氢酶(17β-HSD) mRNA表达(P＜0.01),镉处理组TM3细胞StAR、P450SCC、细胞色素P45017α-羟化酶(P45017α)、3β-HSD与17β-HSD的蛋白表达水平也明显降低,与对照组相比,差异均有统计学意义(P＜ 0.05,P＜0.01).结论 镉抑制小鼠睾丸间质细胞睾酮的分泌,其原因可能与镉抑制间质细胞部分睾酮合成关键酶mRNA和蛋白表达水平有关.

Effects of cadmium on testosterone biosynthesis in mouse leydig cells

Objective To study the effects of cadmium on testosterone biosynthesis in mouse testicular leydig cells. Methods M3 cells (mouse leydig cell line) TM3 cell in cadmium group were incubated with 20 μmol/L CdCl2, the cells and the culture supernatant fluid were collected at 4 h and 8 h after cadmium exposure. TM3 cells in the control group were treated with Dulbecco phosphate-buffered saline (DPBS). The testosterone level was measured by ELISA, the mRNA and protein of expression levels of some testosterone biosynthetic enzymes were measured by RT-PCR and Western blot. Results Cadmium exposure significantly decreased testosterone level in the culture supernatant fluid (P ＜0. 01). Compared with the control group, Cadmium markedly reduced the mRNA expression levels of steroidogenic acute regulatory protein (StAR), P450 side-chain cleavage enzyme (P450scc ) and 17β-hydroxysteroid dehydrogenase (17β-HSD) (P ＜0. 01). Moreover, the protein expression levels of StAR, P450SCC, P45017α-hydroxylase enzyme(P45017α ) 3β-HSD and 17β-HSD were also downregulated in cadmium group (P ＜ 0. 05, P ＜0. 01). Conclusion Cadmium could impair steroidogenesis in mouse leydig cells, the decreased testosterone might partially contribute to the inhibition to some key enzymes for testosterone biosynthesis.