壬基酚对中国林蛙精巢中StAR表达的影响

为研究水体壬基酚(Nonylphenol，NP)污染对两栖动物精巢中类固醇生成急性调节蛋白(StAR)的影响，将雄性成体中国林蛙(Rana chensinensis)分别暴露于c(NP)为10-7，10-6和10-5 mol/L的水体中10，20和30 d.取其精巢组织，在成功扩增获得273 bp的StAR cDNA片段后合成探针，用原位杂交方法检测StAR mRNA在精巢的表达，用免疫组织化学方法检测StAR蛋白的表达.结果在对照组和各NP处理组中均检测到StAR mRNA和蛋白的阳性表达，阳性反应主要在精巢的Leydig细胞.StAR表达相对值的检测结果表明，c(NP)为10-5 mol/L 的水体对StAR表达有抑制趋势，c(NP)为10-7和10-6 mol/L 的水体可上调StAR的表达，表明NP对StAR表达由抑制转向诱导的临界浓度在c(NP)为10-6 mol/L与10-5 mol/L 之间.在c(NP)为10-7和10-6 mol/L 处理组，StAR表达值随c(NP)的增高而增加.在c(NP)为10-6 mol/L 处理组，暴露30 d后StAR表达相对值最大，呈现NP对StAR表达具有累积效应.c(NP)为10-7 mol/L对StAR表达不随时间延长显示累积效应.提示一定剂量范围的NP可通过调控StAR的表达干扰动物类固醇激素的合成. 

Effects of Nonylphenol on StAR Expression in the Testes of Frog Rana Chensinensis

In order to investigate the effects of nonylphenol(NP) in water environments on the expression of the steroidogenic acute regulatory protein(StAR) in the testes of amphibians,adult male frogs Rana chensinensis were exposed to 10-7,10-6,and 10-5 molL of NP for 10,20,and 30 days.Their testes tissues were taken out,and 273 bp StAR cDNA fragments were successfully obtained by amplification for the preparation of the probe.The expression of StAR mRNA in the testes was examined by in situ hybridization,and the relative intensity of StAR protein expression was tested by immunohistochemistry.The results showed that the positive response of StAR mRNA and protein showed mostly in the Leydig cells of the testes of the frogs treated with NP and the control groups.The relative intensity of the StAR protein showed that the relative intensity of StAR was reduced in the c(NP) of the 10-5 mol L group.In contrast,the c(NP) of the 10-7 and 10-6 mol L groups showed elevated StAR protein expression.It can be inferred that the critical concentration at which StAR expression changes from down-regulated to up-regulated in testes of R.chensinensis is between c(NP) of 10-6 mol L and 10-5 mol L.In c(NP) of the 10-7 and 10-6 mol L treated groups,StAR expression was up-regulated along with the increase of the NP concentration.In c(NP) of the 10-6 mol L treated group,StAR expression was cumulative because of its relative intensity,reaching the highest value under 30 d exposure.In contrast,StAR expression was not cumulative with prolonged treatment time in c(NP) of the 10-7 mol L treated group.These results indicate that certain doses of NP can disturb steroid synthesis by changing StAR expression.