Sublethal effects induced by captopril on Cyprinus carpio as determined by oxidative stress biomarkers

To our knowledge, this is the first study to evaluate captopril-induced oxidative stress in fish, and specifically in the common carp Cyprinus carpio. At present, very few studies in the international literature evaluate the sublethal effects of captopril on aquatic organisms such as fish, and available ones focus on determination of median lethal concentration in crustaceans and algae. Also, studies evaluating these effects do not make reference to the mechanism of action of this pharmaceutical or its toxicokinetics. This limits our knowledge of the characterization of the sublethal effects of this medication and of its potential ecological impact. The present study aimed to evaluate the sublethal effects induced by three different concentrations of captopril, on C. carpio), by determination of activity of the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx), as well as indicators of cellular oxidation: hydroperoxide content (HPC), lipid peroxidation (LPX) and protein carbonyl content (PCC). Specimens were exposed for 12, 24, 48, 72 and 96h to three different captopril concentrations: 1μgL^-1, 1mgL^-1 and 100mgL^-1 (the first one has been detected environmentally, the other two have been associated with diverse toxic effects in aquatic species), and brain, gill, liver, kidney and blood samples were evaluated. Significant increases in HPC and LPX were observed mainly in kidney and gill, while PCC also increased in brain. Modifications were found in the activity of SOD (mostly in kidney, brain and blood), CAT (all organs) and GPx (kidney and gill). In conclusion, captopril induces oxidative stress in C. carpio.