目的：己烯雌酚（diethylstilbestrol，DES）可以导致睾丸氧化损伤，而氧化损伤则可能是导致类固醇合成障碍的作用机制之一。本文探讨DES导致睾丸氧化损伤与睾酮合成途径的关系及可能的机制。方法24只健康4周龄雄性Wistar大鼠，随机分为4组，即对照组（玉米油）和DES染毒组（0.1、1.0、10.0μg／kg ），每组6只，皮下注射每日1次，连续染毒8周。染毒结束后称量动物体重及雄性生殖器官和附属生殖器官（睾丸、附睾、前列腺）的重量，用生化方法检测睾丸匀浆中丙二醛（ MDA）和活性氧自由基（ ROS）的含量，抗氧化酶超氧化物歧化酶（SOD）、过氧化氢酶（CAT）、谷胱甘肽过氧化物酶（GPx）的活性变化以及类固醇合成酶3β羟类固醇脱氢酶1（3β-HSD1）、17β羟类固醇脱氢酶3（17β-HSD3）的活性，用放射免疫法测定外周血中睾酮、促黄体生成素（LH）的水平，用RT-PCR检测固醇激素急性调节蛋白（StAR）、P450胆固醇侧链裂解酶（P450scc）、3β羟类固醇脱氢酶1（3β-HSD1）、17β羟类固醇脱氢酶3（17β-HSD3） mRNA水平的表达变化。结果10.0μg／kg组睾丸、前列腺重量以及脏器系数明显减少，MDA和ROS的氧化程度明显升高，SOD、CAT、GPx的活性降低，3β-HSD1、17β-HSD3的活性分别降低；血清睾酮降低，1.0μg／kg组LH降低，整个染毒区间呈现剂量效应关系；10.0μg／kg组StAR、P450scc、3β-HSD1、17β-HSD3 mRNA表达减少，1.0μg／kg组StAR、3β-HSD1依然减少。结论 DES暴露干扰了大鼠睾丸氧化／抗氧化平衡，同时导致包括睾酮水平降低在内的雄性生殖危害。 DES导致GPx、CAT酶活力降低，抑制睾丸类固醇合成途径中P450scc，3β-HSD1 mRNA的表达水平，以及3β-HSD1活性降低导致睾酮减少。推测该途径可能是DES干扰类固醇合成的毒性作用机制之一。%Objective It is well known that diethylstilbestrol ( DES ) can result in testicular oxidative injury , and one of its mechanisms of action is leading to dysfunction of steroidogenesis .The aim of this study was to investigate the relationship between testicular oxidative injury caused by DES and the key synthetase activities for the synthesis pathway of steroidogenesis and the possible mechanism .Methods Twenty-four 4-wk-old male Wistar albino rats were randomly divided into 4 groups , 6 rats each.Three doses of DES (0.1, 1.0 and 10 μg/kg· d) groups and a vehicle (corn oil) control group , were respectively administered by subcutaneous injection once a day for eight weeks .The rats were sacrificed after 8 weeks treatment and the body weight , testis, epididymis, prostate were weighed, respectively.The testicular tissues were homogenized and the oxidation of MDA and ROS , the activity changes of antioxidases SOD, CAT and GPx, as well asthe activities of steroid synthetases 3β-HSD1 and 17β-HSD3 were determined by biochemical measurement.The levels oftestosterone and LH in peripheral blood were measured by radioimmunoassay .The intensities of expression of StAR,P450scc, 3β-HSD1, 17β-HSD3-mRNA were detected by PCR.Results In the 10.0 μg/kg dose group, the weights andorgan coefficients of testis and prostate were decreased significantly , the oxidation of MDA and ROS was increased distinctlyand the activities of SOD, CAT, GPx, 3β-HSD1 and 17β-HSD3 were reduced.The concentration of serum testosterone wasdecreased in the 10.0 μg/kg dose group.In the 10.0 μg/kg and 1.0 μg/kg dose groups, the decline of LH levelpresented a dose-dependent manner, and the intensities of immunochemical positive staining for StAR , P450scc, 3β-HSD1and 17β-HSD3 mRNA were decreased.Conclusions DES exposure results in disturbance of the oxidant /antioxidantbalance and decline of testosterone level that induces reproductive impairment in male rats .DES induces reductions of bothGPx and 3β-HSD activities which cause the decrease of testosterone synthesis .The expression of P450scc and 3β-HSDmRNA,which are the key synthetases in biosynthetic pathway of steroidogenesis , are inhibited by DES, and it isspeculated that the disturbance of steroidogenic synthesis enzymes may be one of the mechanisms of toxic effects of DES .
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