Background: Bisphenol-A (BPA) has estrogenic activity and adversely affects humans and animals' reproductive systems and functions. There has been a disagreement with the safety of BPA exposure at Tolerable daily intake (TDI) (0.05 mg/kg/d) value and non-observed adverse effect level (5 mg/kg/d). The current study investigated the effects of BPA exposure at various doses starting from Tolerable daily intake (0.05 mg/kg/d) to the lowest observed adverse effect level (50 mg/kg/d) on the testis development in male mice offspring. The BPA exposure lasted for 63 days from pregnancy day 0 of the dams to post-natal day (PND) 45 of the offspring. Results: The results showed that BPA exposure significantly increased testis (BPA ≥ 20 mg/kg/d) and serum (BPA ≥ 10 mg/kg/d) BPA contents of PND 45 mice. The spermatogenic cells became loose, and the lumen of seminiferous tubules enlarged when BPA exposure at 0.05 mg/kg/d TDI. BPA exposure at a low dose (0.05 mg/kg/d) significantly reduced the expression of Scp3 proteins and elevated sperm abnormality. The significant decrease in Scp3 suggested that BPA inhibits the transformation of spermatogonia into spermatozoa in the testis. The RNA-seq proved that the spliceosome was significantly inhibited in the testes of mice exposed to BPA. According to the RT-qPCR, BPA exposure significantly reduced the expression of Snrpc (BPA ≥ 20 mg/kg/d) and Hnrnpu (BPA ≥ 0.5 mg/kg/d). Conclusions: This study indicated that long-term BPA exposure at Tolerable daily intake (0.05 mg/kg/d) is not safe because low-dose long-term exposure to BPA inhibits spermatogonial meiosis in mice testis impairs reproductive function in male offspring.

This study examines the impact of Bisphenol A (BPA), a prevalent environmental estrogenic toxicant, on the ovarian development of mice. Mice were exposed to varying BPA doses from in utero to postnatal stages, up to weaning (day 21, PND 21) and puberty (day 45, PND 45). The BPA content in the serum of the offspring mice on PND 45 was higher than that of the mice sacrificed at PND 21. However, the ovary organ index of the mice of PND 21 was significantly increased, and the ovarian structure was damaged when exposed to BPA. In contrast, the mice with PND 45 did not show apparent ovarian lesions. On the other hand, granulosa cell apoptosis was detected in both PND 21 and PND 45 mice ovaries, and ERβ was increased under the influence of BPA. Transcriptomic analysis revealed BPA’s significant impact on ribosomal gene expression, marked downregulation of Rpl21 and Rpsa, and upregulation of Rps2 in both age groups. These transcriptomic alterations were further corroborated by real-time PCR, highlighting a dose-dependent effect of BPA on Rps2. Our findings confirm BPA’s detrimental effects on ovarian health, with more pronounced damage in younger mice, suggesting heightened vulnerability in this group. The study underscores ribosomes as critical targets in BPA-induced ovarian developmental disruptions.

BackgroundBisphenol-A (BPA) has estrogenic activity and adversely affects humans and animals' reproductive systems and functions. There has been a disagreement with the safety of BPA exposure at Tolerable daily intake (TDI) (0.05 mg/kg/d) value and non-observed adverse effect level (5 mg/kg/d). The current study investigated the effects of BPA exposure at various doses starting from Tolerable daily intake (0.05 mg/kg/d) to the lowest observed adverse effect level (50 mg/kg/d) on the testis development in male mice offspring. The BPA exposure lasted for 63 days from pregnancy day 0 of the dams to post-natal day (PND) 45 of the offspring. ResultsThe results showed that BPA exposure significantly increased testis (BPA ≥20mg/kg/d) and serum (BPA ≥10mg/kg/d) BPA contents of PND 45 mice. The spermatogenic cells became loose, and the lumen of seminiferous tubules enlarged when BPA exposure at 0.05 mg/kg/d TDI. BPA exposure at a low dose (0.05 mg/kg/d) significantly reduced the expression of Scp3 proteins and elevated sperm abnormality. The significant decrease in Scp3 suggested that BPA inhibits the transformation of spermatogonia into spermatozoa in the testis. The RNA-seq proved that the spliceosome was significantly inhibited in the testes of mice exposed to BPA. According to the RT-qPCR, BPA exposure significantly reduced the expression of Snrpc (BPA ≥20 mg/kg/d) and Hnrnpu (BPA ≥0.5 mg/kg/d). ConclusionsThis study indicated that long-term BPA exposure at Tolerable daily intake (0.05 mg/kg/d) is not safe because low-dose long-term exposure to BPA inhibits spermatogonial meiosis in mice testis impairs reproductive function in male offspring.