In recent years, studies have focused on the combined ecological risks posed by microplastics and other organic pollutants. Although both microplastics and progestin residues are frequently detected in the aquatic environments, their ecological implications remain unknown. Adult zebrafish were exposed to polystyrene microplastics (PS, 200 nm, 200 μg/L), norethindrone (NET, 69.6 ng/L), and their mixture (200 μg/L PS + 63.1 ng/L NET) for 30 days. The results demonstrated that exposure to PS and NET resulted in gill damage. Notably, the PS and PS+NET exhibited a significant decrease in glutathione (GSH) and oxidized glutathione (GSSG) content, as well as reduced antioxidase activity in the gills. The oxidative stress in PS+NET primarily originated from PS. The PS, NET, or their mixture resulted in a decrease in testosterone (T) and estradiol (E2) levels in female. Furthermore, compared to NET, the PS+NET showed a significant reduction in E2 levels, thereby augmenting the inhibitory effect on reproductive ability mediated by NET. However, males showed an increase in 11-ketodihydrotestosterone (11-KT) content, accompanied by a significant decrease in spermatogonia (Sg) and increase in spermatocytes (Sc). Consequently, it can be inferred that PS enhances the androgenic effect of NET. In female fish brain, NET alone resulted in transcriptional down-regulation of partial hormone receptors; however, co-administration of PS effectively mitigated the interference effects. Furthermore, transcriptional downregulation of 17-alpha-hydroxylase (cyp17), hydroxysteroid 3-beta dehydrogenase (hsd3b), estrogen receptor 1 (esr1), and estrogen receptor 2a (esr2b) genes in the ovary was found to be associated with the androgenic activity induced by NET. Moreover, in comparison to PS or NET alone, PS+NET resulted in a notable decrease in Cetobacterium abundance and an increase in Aeromonas population, suggesting that the co-exposure of PS+NET may exacerbate intestinal burden. The findings highlight the importance of studying the combined toxicity of PS and NET.

中文翻译：

---

共同暴露于聚苯乙烯微塑料和炔诺酮对斑马鱼鳃组织学、抗氧化能力、生殖系统和肠道微生物群的影响 （Danio rerio）


近年来，研究主要集中在微塑料和其他有机污染物带来的综合生态风险上。尽管在水生环境中经常检测到微塑料和孕激素残留物，但它们的生态影响仍然未知。成年斑马鱼暴露于聚苯乙烯微塑料 （PS， 200 nm， 200 μg/L）、炔诺酮 （NET， 69.6 ng/L） 及其混合物 （200 μg/L PS + 63.1 ng/L NET） 30 天。结果表明，暴露于 PS 和 NET 会导致鳃损伤。值得注意的是，PS 和 PS+NET 的谷胱甘肽 （GSH） 和氧化谷胱甘肽 （GSSG） 含量显著降低，鳃中的抗氧化酶活性降低。PS+NET 中的氧化应激主要来源于 PS。PS、NET 或其混合物导致女性睾酮 （T） 和雌二醇 （E2） 水平降低。此外，与 NET 相比，PS+NET 显示 E2 水平显著降低，从而增强了 NET 介导的对生殖能力的抑制作用。然而，雄性显示 11-酮二氢睾酮 （11-KT） 含量增加，伴随着精原细胞 （Sg） 和精母细胞 （Sc） 的显着减少。因此，可以推断 PS 增强了 NET 的雄激素作用。在雌鱼脑中，单独的 NET 导致部分激素受体的转录下调;然而，PS 的共同给药有效地减轻了干扰效应。此外，发现卵巢中 17-α-羟化酶 （cyp17） 、羟基类固醇 3-β 脱氢酶 （hsd3b） 、雌激素受体 1 （esr1） 和雌激素受体 2a （esr2b） 基因的转录下调与 NET 诱导的雄激素活性有关。 此外，与单独使用 PS 或 NET 相比，PS+NET 导致鲸杆菌丰度显着降低，气单胞菌数量增加，表明 PS+NET 的共同暴露可能会加剧肠道负担。研究结果强调了研究 PS 和 NET 联合毒性的重要性。