Pro-oxidant and antioxidant response in the kidney of an endemic mexican fish (Goodea gracilis) exposed to CH2Cl2, CHCl3 and BrCHCl2.

Abstract

It has been shown that the isoform 2E1 of CYP 450 (CYP 2E1) and theta isoform of glutathione S-transferase (GSTT) are involved in the biotransformation of halomethanes (HMs) in mammals, which are disinfection by-products of water. In this study, a set of biomarkers related to exposure to these toxicants in the kidney of Goodea gracilis (a Mexican endemic fish) treated with CH₂Cl₂ (0.006, 0.03, 0.06, 0.06 and 6 mg L^-1), CHCl₃ (0.01, 0.1, 1, 10 and 100 mg L^-1) and BrCHCl₂ (0.002, 0.01, 0.1, 1, 10 mg L^-1) were evaluated. Only activity of CYP 2E1 induced by BrCHCl₂ and CH₂Cl₂ was higher than controls. GSTT metabolism and pro-oxidant forces (O₂•, H₂O₂ and CH₂O) were irregular regarding treatments and controls. Damage to cell membranes (ROOH and SRATB) showed a similar trend among the HMs. Protein oxidation was lower than controls except the one caused by the CHCl₃. The CH₂Cl₂ stimulated the enzymes involved in the antioxidant defense (superoxide dismutase, catalase and glutathione peroxidase), as also occurred with total glutathione S-transferase, while the others HM elicited an irregular response. These findings suggest that toxic effects elicited by HM on the kidney of fish are complex and more studies are needed to expand knowledge on the subject.