Estrogenic properties of municipal and industrial wastewaters evaluated with a rapid and sensitive chemoluminescent in situ hybridization assay (CISH) in rainbow trout hepatocytes

Abstract

The estrogenic properties of municipal and industrial wastewaters were examined using rainbow trout hepatocytes. Primary cultures of rainbow trout hepatocytes were exposed to several concentrations of industrial/municipal wastewaters for 48 h at 15°C. Estrogenicity was evaluated on the basis of the amount of vitellogenin (Vg), as determined by the alkali-labile phosphate method, excreted into the extracellular media and vitellogenin gene expression (mRNA) by a novel and very sensitive chemoluminescent in situ hybridization assay (CISH). The results show that exposure of hepatocytes to estradiol increased Vg level present in the incubation media and Vg mRNA as estimated by the CISH method. It was also found that effluents from industries that process natural products (paper recycling) and some municipal wastewaters, ultimately discharged into the St. Lawrence River, were estrogenic to hepatocytes. In addition, anti-estrogenic effects were observed in wastewater samples from the most heavily populated towns, while those from smaller towns exhibited estrogenicity to trout hepatocytes. It is suggested that the industrial component of municipal discharges is likely to contribute to anti-estrogenicity. Primary cultures of rainbow trout hepatocytes are useful means to assess the effects of complex mixtures on Vg gene expression and Vg protein secretion.