三苯基锡对褐菖鮋精巢发育的影响及其作用机制

Effect of triphenyltin on the testicular development in Sebastiscus marmoratus and its action mechanism

三丁基锡(tributyltin,TBT)和三苯基锡(triphenyltin,TPT)广泛应用于海洋船只防污涂料。但相对于TBT,对TPT的毒性研究还很少。本实验以海洋经济鱼类褐菖鲉(Sebastiscus marmoratus)为对象,研究环境水平TPT对精巢发育的影响。研究发现,TPT降低精巢的精子数目和密度,增加精小叶间隙脂滴数量和精巢总脂质水平。另外,TPT降低精巢睾酮酯化水平,增加游离睾酮水平,降低游离17β-雌二醇水平。TPT对精巢发育的抑制可能与精小叶间隙脂质水平的增加及精巢17β-雌二醇水平的降低有关。实验结果为全面了解TPT产生鱼类生殖毒性效应、途径和机制提供了新的重要资料。环境水平的TPT能够抑制精巢的发育,而且毒性要高于TBT。这些结果为海洋环境政策的制定和评估有机锡污染对海洋鱼类资源的影响提供了重要的依据。

The worldwide use of two triorganotin compounds,triphenyltin（TPT） and tributyltin（TBT） as fungicides and pesticides in agricultural activities and as ingredients of antifouling paints,have caused the contamination of aquatic environment globally.Much attention have been paid to pollution by TBT due to the fact that TBT dominated over TPT in usage amount as antifouling paint ingredients.Recently,an increasing number of studies reported unexpectedly high levels of TPT in fishes around the world,because TPT could be easily absorbed and accumulate in fishes.While the effects of TBT on reproduction in fishes have been studied widely during the past decade,few studies have addressed the reproductive toxicity of TPT.Therefore,experiments were conducted to investigate the effects of TPT at environmentally relevant concentrations on testicular development in male rockfish Sebastiscus marmoratus and to gain insight into its mechanism of action.After exposure for 48 days,TPT inhibited the testicular development.The tests from individuals exposed to 1 ng/L of TPT showed mature sperm in the lobule lumina,but fewer than that in the control.Mature sperm was not found in the lobule lumina of 10 ng/L TPT group.TPT depressed the esterification of testosterone and elevated the free testosterone levels.Although the free testosterone levels in the tests were elevated,spermatogenesis was suppressed.As 17β-estradiol played an important role in spermatogenesis in fish,the decrease of free 17β-estradiol levels may have contributed to the inhibition of testicular development caused by TPT.In addition,TPT exposure resulted in enlargement of lipid droplets in the interlobular septa and increases of total lipid in the tests,which might have been one of the reasons causing the dysfunction of Sertoli cells,inhibiting the development of spermatogenesis.TPT interfering with lipid in the testes might be another factor depressing the testicular development.Results provided new information for fully understanding the reproductive effects and action mechanism of TPT.TPT at the environmental levels can inhibit the testicular development,and was more poisonous than TBT.Results provided important evidences for making marine environment policies and evaluating effects of organotin compounds on resources of marine fish.