Juvenile sea bass (Dicentrarchus labrax L.) DNA strand breaks and lipid peroxidation response following 17beta-estradiol two mode of exposures

Juvenile Dicentrarchus labrax L. (sea bass) were exposed to water diluted 17beta-estradiol (E2) (200 ng/L and 2000 ng/L) and treated with intraperitoneal (i.p) injection E2 (0.5 mg/kg and 5 mg/kg) during 10 days in order to study its genotoxicity and peroxidative damage, measured as gill, blood, liver and kidney DNA integrity decrease using DNA strand breaks assay as well as liver, gill and kidney lipid peroxidation (LPO) respectively. Juvenile sea bass gill DNA integrity was significantly decreased for all E2 exposure conditions. However, no differences were detected either between different exposure routes or tested concentrations. Blood DNA integrity was significantly decreased by E2 5 mg/kg as well as by both water diluted E2 exposure conditions. The highest E2 dose (5 mg/kg) also promoted liver DNA integrity decrease. Liver and gill LPO significantly increased at the highest E2 i.p treatment. An increasing trend of gill and liver LPO, though statistically insignificant, was observed in D. labrax exposed to water diluted E2 in both tested concentrations. The current results demonstrated that DNA damage in juvenile sea bass is affected by the E2 exposure conditions, such as water diluted E2 versus i.p E2 injection since i.p E2 injection promoted higher genotoxicity effect, in terms of affected organs than water diluted E2. Moreover, the organ sensitivity to E2 was different, since gill showed more susceptibility than blood, liver and kidney. Concerning kidney LPO and DNA integrity no differences were found between treated and controls juvenile sea bass groups.