Avaliação da ecotoxidade de losartana potássica em Astyanax altiparanae (lambari) através de ensaio cometa e biomarcadores bioquímicos

Abstract

Antihypertensives are among the most widely consumed drugs in the world and therefore often found in nature. However, their effects on non-target organisms are still unknown. In this therapeutic class, losartan potassium is the main agent consumed in Brazil. Studies have reported considerable concentrations of losartan in aquatic environments (μg L-1) and in effluents, where it has already been found at mg L-1 range. In this way, investigations on the first ecotoxic parameters of losartan potassium are of great biological importance. This study evaluated the influence of losartan on genetic biomarker and biochemical biomarkers in the species Astyanax altiparanae (lambari). The experiments were divided into two steps. In Step 1, subjects were exposed to a fixed concentration of losartan (2.5 mg L-1) at exposure times of 6, 12, 24 and 48 h. The comet assay showed reduced DNA damage scores at the time of exposure for 12 h, which may suggest a protective effect. For GSH and GST, respectively, increased concentration and inhibition of enzyme activity was observed, whereas AChE activity was not altered. In Step 2 only biochemical biomarkers were analyzed. Losartan was tested at concentrations of 0.25 mg L-1 and 2.5 mg L-1 in single exposure time (24 h). At this stage, the AChE activity and the GSH concentration were not altered. For GST, induction of enzymatic activity was observed during the fish exposure at drug concentration of 2.5 mg L-1. The relationship between time and observed effects could not be fully defined, but it was found that biomarkers may respond differently according to the time of exposure. Losartan did not show neurotoxicity to fish, but the results indicate possible oxidative stress.