Rempel-Hester Mary Ann, Hong Haizheng, Wang Yinsheng, Deng Xin, Armstrong Jeff, Gully Joe, Schlenk Daniel
Environmental Toxicology Graduate Program, University of California Riverside, Riverside, CA, USA.
Environ Res. 2009 Jul;109(5):552-8. doi: 10.1016/j.envres.2009.02.006. Epub 2009 Mar 14.
Studies throughout the southern California bight have indicated persistent estrogenic activity in male hornyhead turbot (Pleuronichthys verticalis). Plasma 17beta-estradiol (E2) concentrations correlated with gonadal DNA damage in fish collected near a wastewater treatment plant outfall, but not from fish collected at the reference location. When the same species was collected from the same reference location and treated with E2, no relationship between uptake and gonadal DNA damage was observed. To evaluate the site-specific effects of E2 in fish from a wastewater outfall and fish from a reference location, male hornyhead turbot from each location were exposed to 15 microg/L aqueous E2 in a time-course experiment, with fish sampled every 12 h for 48 h. Concentrations of E2 were measured in the aqueous exposure and in plasma from the fish. Vitellogenin (vtg) was also measured in the plasma, and 8-oxo-7,8-dihydro-2'-deoxyguanosine levels in male gonads were measured as an indicator of DNA damage. Untreated fish from the outfall had significantly lower E2 in the plasma relative to the untreated reference fish, and this trend was consistent at each time point in the E2-treated fish. Vtg was significantly induced after 36 h of exposure in fish from both sites and no significant differences were observed between the sites. A significant increase of oxidative DNA damage was observed in E2-treated fish from the outfall population and the damage was significantly correlated with plasma E2 concentrations only in fish from the outfall after 48 h. These results indicated that there were significant differences in E2 disposition and gonadal genotoxicity between the hornyhead turbot populations following exposure to E2, suggesting that fish at wastewater outfalls may be more sensitive to DNA damage, which may be temporally related to concentrations of E2 in plasma.
整个南加州湾的研究表明，雄性角头鲽（Pleuronichthys verticalis）体内存在持续的雌激素活性。在靠近污水处理厂排水口采集的鱼类中，血浆17β-雌二醇（E2）浓度与性腺DNA损伤相关，但在参考地点采集的鱼类中未发现这种相关性。当从同一参考地点采集同一物种并用E2处理时，未观察到摄取与性腺DNA损伤之间的关系。为了评估E2对来自污水处理厂排水口的鱼类和来自参考地点的鱼类的位点特异性影响，在一项时间进程实验中，将来自每个地点的雄性角头鲽暴露于15微克/升的水性E2中，每12小时对鱼类进行采样，持续48小时。测量水性暴露液和鱼血浆中的E2浓度。还测量血浆中的卵黄蛋白原（vtg），并测量雄性性腺中的8-氧代-7,8-二氢-2'-脱氧鸟苷水平作为DNA损伤的指标。相对于未处理的参考鱼，来自排水口的未处理鱼血浆中的E2显著较低，并且在E2处理的鱼的每个时间点这种趋势都是一致的。暴露36小时后，两个地点的鱼的vtg均被显著诱导，且两个地点之间未观察到显著差异。在来自排水口种群的E2处理鱼中观察到氧化DNA损伤显著增加，并且仅在48小时后，这种损伤仅在来自排水口的鱼中与血浆E2浓度显著相关。这些结果表明，暴露于E2后，角头鲽种群之间在E2处置和性腺遗传毒性方面存在显著差异，这表明污水处理厂排水口处的鱼类可能对DNA损伤更敏感，这可能与血浆中E2的浓度在时间上相关。
