双酚A对大鼠未成熟Leydig细胞类固醇代谢关键酶基因表达的影响

Effect of bisphenol A on gene expression of steroidogenic key enzyme in immature rat Leydig cell

目的:观察双酚A(bisphenol A,BPA)对大鼠未成熟Leydig细胞睾酮合成及类固醇代谢关键酶表达水平的影响。方法:出生后第21天雄性SD大鼠24只,随机均分成4组:对照组、低剂量组(2.4μg/kg)、中剂量组(1 mg/kg)、高剂量组(200 mg/kg)。实验组每天分别给予不同剂量的BPA灌胃,对照组给予等容积的玉米油灌胃。第35天腹主动脉取血处死大鼠,光镜、透射电镜下观察睾丸Leydig细胞的形态及超微结构的改变;酶联免疫吸附试验(ELISA)法检测大鼠血清睾酮浓度;逆转录-聚合酶链反应(RT-PCR)法检测类固醇激素合成急性调节蛋白(StAR)、3β-羟甾脱氢酶(3β-HSD)、17β-羟甾脱氢酶(17β-HSD)、细胞色素P450侧链裂解酶(P450scc)、细胞色素P45017α-羟化酶(P450c17)和细胞色素P450芳香酶(P450arom)mRNA的表达。结果:低剂量组大鼠血清睾酮浓度下降(P<0.05),睾丸组织P450scc及3β-HSD mRNA的表达下降(P<0.05);中剂量组大鼠血清睾酮维持正常水平,各关键酶mRNA表达未见明显改变;高剂量组大鼠血清睾酮维持正常水平,睾丸Leydig细胞线粒体肿胀明显、线粒体嵴排列紊乱,睾丸组织StAR及17β-HSD mRNA的表达下降(P<0.05),而3β-HSD mRNA的表达升高(P<0.05)。各组大鼠睾丸Leydig细胞光镜下形态均未见明显异常。结论:BPA可能通过Leydig细胞线粒体损伤及类固醇代谢关键酶的变化影响大鼠未成熟Leydig细胞的睾酮合成。

Objective： To observe the effects of bisphenol A （BPA） on testosterone biosynthesis and genesexpression of steroid synthesis key enzyme in rat immature Leydig cell. Methods： Twenty-four male Sprague-Dawley weaning rats were randomly divided into four groups： control group, low dose group （2.4 μg/kg）, middledose group （1 mg/kg）, high dose group （200 mg/kg）. Experimental groups were received at the diverse dosage of BPA per day from post-natal day 21 to 35 by gavage. The control group was received corn oil at the same volume.The morphologic change of Leydig cell was observed under light microscopy （LM） and transmission electron microscopy （TEM） respectively. Serum testosterone was measured by ELISA. Genes expressions of STAR, 3β-HSD, 17 β-HSD, P450scc, P450c17 and P450arom in the testis were measured by reverse transcription-polymerase chain reaction （RT-PCR）. Results： Decrease of serum testosterone （P〈0.05） and the gene expression ofP450scc and 3β-HSD （P〈0.05） were detected in low dose group. In middle dose group, serum testosterone and the key enzyme gene expression were no significant changes compared with control group. In high dose group, serumtestosterone maintained normal level, but mitochondria swelling and cristae derangement in Leydig cells were observed under TEM. The gene expression of StAR and 17β-HSD （P〈0.05） were decreased, but 3β-HSD mRNA （P〈0.05） was increased in high dose group. There was no morphological abnormality of Leydig cell from different group under LM. Conclusion： BPA may interfere with the ability of testosterone biosynthesis through the damage of themitochondria and change of the gene expression of steroidogenic key enzymes in the Leydig cell of immature rat.