Evaluation of toxicity and non-motor symptoms of Parkinson-like induced by rotenone in zebrafish animal model

In this study, the effects of exposure to rotenone on development were evaluated, particularly teratogenic and behavioral endpoints in the early life stages of zebrafish. This can serve as a model for Parkinson-like motor and non-motor symptoms, and anxiety-like behavior. The endpoints of percent epiboly, teratogenic effects, mortality, morphometry, thigmotaxis (TH), touch sensitivity (TS), and optomotor response (OMR) were analyzed in zebrafish embryo-larvae stage exposed to rotenone (5 to 20 µg/L). An increase in mortality of zebrafish was observed at 15 and 20 µg/L rotenone concentrations. The rotenone reduced the percent epiboly and increased the presence of teratogenic effects at concentrations of 10, 15, and 20 µg/L. Head and body size reductions were observed at all rotenone concentrations tested. Anxiety-like behaviors were observed with decreased displays of TH behavior in larvae exposed to 15 and 20 µg/L of rotenone. TS was reduced by 20 µg/L rotenone treatment. OMR and the eye diameter of zebrafish were not affected by rotenone exposure. Our results showed that rotenone has the potential to provoke non-motor symptoms, mainly anxiety-like behaviors, in the zebrafish's early life stages, making it a potential model for the study of Parkinson-like disease.