Bisphenol AF (BPAF) jeopardizes male fertility and triggers intergenerational defects in zebrafish (Danio rerio)

The plasticizer Bisphenol AF (BPAF) is an emerging contaminant used in industrial production due to its high thermal and chemical stability. However, it poses a threat to public health and ecosystems. BPAF is an endocrine-disrupting xenoestrogen that can interfere with the hypothalamic-pituitary-gonadal axis and dysregulate steroid synthesis. In this study, adult male zebrafish were exposed to an environmentally relevant concentration of BPAF (0.15 μg/L) for 14 days. The effects on 11-Ketotestosterone (11-KT) synthesis, spermatogenesis, and sperm quality were assessed. Additionally, we investigated potential impacts of BPAF on paternal information by breeding with untreated females, evaluating intergenerational effects such as delayed hatching rates, malformations, decreased survival, and gene expression changes in the offspring (F1). Furthermore, the same parameters were examined in embryos directly exposed to 0.15 μg/L BPAF. BPAF stimulated the differentiation of both meiotic (spermatocytes) and post-meiotic (spermatids) cysts alongside with up-regulation of the meiotic prophase marker gene expression (sycp3l).. However, the differentiation observed in spermatogenesis did not appear to be mediated by 11-KT as its plasma or testicular concentrations did not show significant differences.. BPAF exposure stimulated a range of genes involved in epigenetic regulation (tet1, ezh2, kdm6b, kat6a, and hdac4) in the testes and significantly reduced sperm motility. In the F1 offspring, there was evidence of paternal information modification, including substantial delays in hatching rates, increased mortality, and elevated mRNA levels of the genes vegfa and cyp19a1b after 96 h post-fertilization (hpf). Similarly, embryos/larvae directly exposed to BPAF showed delayed hatching rates (at 72 h), increased mortality, and significant changes in gene expression, disrupting genes related to development (mstn1, vegfa, and wnt8), estrogen (esr1, cyp19a1b, and vgt1), and androgen (hsd11β2). This study highlights the need to understand the effects of BPAF and its potential impacts on ecosystems, questioning its viability as an alternative to BPA.