邻苯二甲酸单乙基己基酯对原代培养大鼠睾丸Leydig细胞睾酮合成的影响

Effects of Mono(2-ethylhexyl) Phthalate on Testosterone Biosynthesis in Leydig Cells Cultured from the Rat Testis

目的:探讨邻苯二甲酸二乙基己基酯(DEHP)的代谢产物邻苯二甲酸单乙基己基酯(MEHP)对SD大鼠体外培养睾丸间质细胞(Leydigcells)睾酮合成的影响。方法:建立SD大鼠睾丸Leydig细胞体外原代培养模型,MEHP染毒剂量组分为对照(0μmol/L)、62.5、125、250、500、1000μmol/L,通过噻唑蓝(MTT)法观察线粒体活性,放射免疫法测定睾酮浓度,RTPCR法测定Leydig细胞类固醇合成急性调节蛋白(StAR)mRNA表达。结果:MEHP染毒24h后,Leydig细胞线粒体活性在250μmol/L时显著上升,1000μmol/L时显著下降,与对照组比较,差异均有显著性(P<0.01)。基础状态及人绒毛膜促性腺激素(hCG)刺激状态下,Leydig细胞睾酮合成水平均呈上升趋势,与对照组相比,250、500μmol/L剂量组差异均有显著性(P<0.01)。Leydig细胞StARmRNA的表达在62.5、125、250μmol/L时与对照组相比均未见有显著性改变,在500、1000μmol/L时显著下降(P<0.01)。结论:MEHP直接影响原代培养Leydig细胞线粒体活性及睾酮合成,胆固醇跨膜转运的调节因子StAR与MEHP引起睾酮合成上升的原因可能无关。

Objective:To investigate the effects of mono(2-ethylhexyl)phthalate(MEHP), the primary metabolite of di(2-ethylhexyl)phthalate(DEHP), on testosterone biosynthesis in Leydig cellscultured from the Sprague Dawley rat testis. Methods: Based on the primary Leydig cell culture model, MEHP exposure groups involved control (0 μmol/L), (62.5), 125, 250, 500 and 1 000 μmol/L. We observed mitochondria activity with the MTT method, measured the testosterone level with RIA and determined steroidogenesis acute regulatory protein(StAR) mRNA expression with RT-PCR. Results: After Leydig cells were exposed to MEHP for 24 hours, the activity of mitochondria enhanced evidently at 250 μmol/L and then declined markedly at (1 000) μmol/L compared with the control group(P<(0.01)). The testosterone level showed an increasing tendency in both basal and hCG-stimulated states with statistical significance at 250 and 500 μmol/L compared with the control group(P<(0.01)). However, the expression of StAR mRNA appeared unchanged at (62.5),125 or 250 μmol/L, but exhibited a decreasing tendency at 500 and (1 000) μmol/L(P<(0.01)). Conclusion: MEHP directly affected the activity of mitochondria and testosterone biosynthesis of the Leydig cells in vitro. StAR, the regulator of cholesterol transport into mitochondria, might not be responsible for the increase of testosterone biosynthesis induced by MEHP. Natl J Androl,2005,11(4):247-251