Toxic effects of chronic exposure to BPAF and perturbation of gut microbiota homeostasis in marine medaka (Oryzias melastigma).

Bisphenol AF (BPAF), a substitute for bisphenol A (BPA), exhibits potent endocrine-disrupting properties that pose a serious health hazard to organisms. This study employed marine medaka as a model, subjecting them to different concentrations of BPAF (0.61, 6.65, and 91.88 μg/L) from the embryonic stage for a period of 160 days. Findings showed that 91.88 μg/L BPAF reduced survival rates and altered sex ratios. Furthermore, exposure to BPAF at all concentrations led to a significant increase in body length and weight. Behavioral analysis revealed that BPAF exposure impaired the swimming ability of the medaka. Histological changes included disrupted ovarian development, reduced sperm count, liver inflammation, and intestinal damage. Gene expression analysis revealed impacts on nervous system (e.g., gap43, itr, elavl3), HPG axis (e.g., gthα, erα, 3βhsd), and liver genes (e.g., chgl, vtg2). Additionally, BPAF altered the diversity and richness of gut microbes in marine medaka, leading to significant changes in specific bacterial species and intestinal functions. In conclusion, long-term BPAF exposure induced neurotoxicity, reproductive toxicity, and impaired digestive and immune systems in marine medaka, with sex-specific effects. These results provide further evidence of the potential hazards of BPAF as an environmental pollutant.