Bioaccumulation and reproductive toxicity of bisphenol A in male-pregnant seahorse (Hippocampus erectus) at environmentally relevant concentrations

Seahorses, with brood pouch in adult males, are a bioindicator species that exhibit specialized reproductive strategy of male pregnancy. Bisphenol A (BPA), one of the most pervasive endocrine-disrupting chemicals (EDCs), is hazardous for reproductive, immune, and neurological systems. However, no evidence of BPA toxicity to the male-pregnant animals is available. Herein, the reproductive toxicity of BPA was evaluated in lined seahorses (Hippocampus erectus) following exposure to environmentally relevant concentrations (10, 100, and 1000 mu g/L) through physiological, histological, and transcriptional analyses. Our results indicated BPA bioaccumulation to be positively correlated with exposure doses in both sexes. Ovarian failure was only observed in the high-dose BPA treatment group, accompanied by the apoptosis of follicular cells and up-regulation of proapoptotic genes. However, brood pouches maintenance were surprisingly inhibited at low concentration, and transcriptomic analysis revealed disturbed profiles of genes involved in the extracellular matrix and cell-cell adhesion pathways. Interestingly, seahorse testes were less sensitive to BPA exposure than that in other teleosts. Thus, our study suggests that BPA at environmentally relevant concentrations might cause reproductive dysfunction in seahorses, potentially exerting adverse effects on the seahorse population since most of them inhabit shallow coastal areas with prevalent estrogenic contaminants. (C) 2020 Elsevier B.V. All rights reserved.

Automated summary

This study revealed that exposure to BPA at environmentally relevant concentrations may cause reproductive dysfunction in seahorses. Ovarian failure was observed in the high-dose BPA treatment group, while maintenance of brood pouches was inhibited at low concentrations, suggesting differential impacts of BPA on seahorses.