Effect of a human pharmaceutical carbamazepine on antioxidant responses in brain of a model teleost in vitro: an efficient approach to biomonitoring.

Residual pharmaceuticals are generally recognized as relevant sources of aquatic environmental pollutants. In this study, the effects of carbamazepine (CBZ) on the antioxidant defense system in the brain of rainbow trout in vitro were studied. The brain homogenates were incubated with various concentrations of CBZ (1.0 µg l⁻¹, 0.2 mg l⁻¹ or 2.0 mg l⁻¹) for 0, 60, 120 min. After incubation, oxidative stress indices (lipid peroxidation and carbonyl protein), antioxidant enzymes (superoxide dismutase, glutathione reductase and glutathione peroxidase) and nonenzymatic antioxidant (reduced glutathione) in each samples were measured. Based on the results, the brain homogenates performed adaptive responses to CBZ-induced stress at environmental concentration (1.0 µg l⁻¹). With increased CBZ concentrations (0.2 or 2.0 mg l⁻¹), oxidative stress was apparent as reflected by the significant higher levels of oxidative indices, together with the significant inhibition of all antioxidant enzymes activities and reduced glutathione content. Compared with previous studies in vivo, the brain homogenates showed more sensitive antioxidant responses to CBZ stress. In conclusion, the brain homogenates of rainbow trout could be used as an efficient model system in aquatic risk assessment, but more detailed laboratory studies are needed before these findings could be established as special biomarkers for monitoring residual pharmaceuticals in aquatic environment.