Effects of permethrin exposure (25 and 50 μg/L) in the Nrf2-related antioxidant response in zebrafish larvae. Amplification of the antioxidant system was estimated by fluorescence microscopy using two different zebrafish reporter lines. Expression of EGFP in (a) Tg(HSP70:EGFP) and (b) Tg(EPRE:LUC-EGFP) in zebrafish larvae. Relative fluorescence levels and representative images are shown for each transgenic construct and exposure group. Arrows indicate the presence of cells expressing high fluorescence in the caudal region of zebrafish larvae. Values are expressed as mean ± SEM and were analyzed by one-way ANOVA followed by Tukey post hoc comparison. Groups not sharing letters are significantly different (p < 0.05).

Exposure to permethrin (25 and 50 μg/L) causes genotoxicity in zebrafish larvae. (a) Representative images of single cell gel electrophoresis (comet assay), (b) comet length (average for the control group = 430 microns), and (c) tail length (average for the control group = 195 microns). The dates expressed as median ± interquartile range, analyzed by Kruskal-Wallis followed by Dunn's multiple comparison test. Different letters indicate statistically significant differences (p < 0.05).

Exposure to permethrin (25 and 50 μg/L) causes cell death by apoptosis in zebrafish larvae. The frequency of apoptotic cells was estimated in the head of zebrafish larvae by measuring the total fluorescence in the area. (a) Representative image of the acridine orange staining and fluorescence imaging, indicating the presence of apoptotic cells (white arrows), and (b) the respective quantification of acridine orange relative fluorescence. Values are expressed as mean ± SEM and were analyzed by one-way ANOVA followed by Tukey post hoc comparison. Different letters indicate statistically significant differences (p < 0.05).