Di-(2-ethylhexyl) phthalate (DEHP) possesses the potential to interfere with the male reproductive endocrine system in mammals; however, its reproductive toxicity in male zebrafish and associated epigenetic studies have not been explored. In this study, three-month-old male zebrafish were exposed to environmentally relevant concentrations of DEHP (0, 10, 33 and 100 μg/L) for 3 months, and then the impact on the reproduction of males and the underlying mechanism were investigated. Histological testing showed that an exposure concentration of 100 μg/L DEHP significantly inhibited spermatogenesis, with an associated decline in capability to fertilize untreated oocytes. Electron microscopic examinations also revealed noticeable damage to the testicular ultrastructure at the 100 μg/L DEHP exposure level. In addition, exposure to 33 and 100 μg/L of DEHP resulted in a decline of circulating testosterone (T) and an increase in the level of 17β-estradiol (E2), both of which were possibly derived from the downregulation of cyp17a1 and hsd17b3 genes and the upregulation of the cyp19a1a gene in the gonads. The DNA methylation statuses of these genes were altered within their promoter regions. A significant increase in global DNA methylation in both the male testes and their offspring larvae was observed at higher exposure concentration of DEHP. Our findings demonstrate that exposure to environmentally relevant concentrations of DEHP can damage the testes, disturbe the sex hormones production, and inhibite spermatogenesis, which ultimately impairs the reproduction of male zebrafish.

邻苯二甲酸二（2-乙基己基）酯（DEHP）具有干扰哺乳动物雄性生殖内分泌系统的潜能。然而，尚未探索其在雄性斑马鱼中的生殖毒性和相关的表观遗传学研究。在这项研究中，将三个月大的雄性斑马鱼暴露于环境相关浓度的DEHP（0、10、33和100μg/ L）3个月，然后研究其对雄性繁殖的影响及其潜在机制。 。组织学测试表明，暴露浓度为100μg/ L DEHP会显着抑制精子发生，并伴有使未处理的卵母细胞受精的能力下降。电子显微镜检查还显示，在100μg/ L DEHP暴露水平下，睾丸超微结构受到明显破坏。此外，CYP17A1和hsd17b3基因和上调cyp19a1a性腺基因。这些基因的DNA甲基化状态在其启动子区域内改变。在DEHP暴露浓度较高的情况下，雄性睾丸及其后代幼虫的总体DNA甲基化显着增加。我们的发现表明，与环境相关的DEHP暴露会损害睾丸，扰乱性激素的产生，并抑制精子发生，最终损害雄性斑马鱼的繁殖。