Prenatal Bisphenol B Exposure Induces Adult Male Offspring Reproductive Dysfunction via ERα Inhibition-Triggered MHC I-Mediated Testicular Immunological Responses

As an emerging endocrine-disrupting agent and structural analog of bisphenol A (BPA), bisphenol B (BPB) raises significant concerns due to its potential to induce male reproductive toxicity. Despite its presence in maternal bodily fluids, the effects of BPB exposure on the reproductive system and its mechanisms in adult male offspring are poorly understood. By establishing a maternal BPB exposure model in mice, we found that the exposure reduced the relative weights of seminal vesicles and preputial glands, decreased the thickness of the seminiferous epithelium, enlarged the lumen area of seminiferous tubules, and lowered testosterone concentration and synthesis, as well as sperm count in 10-week-old male offspring. Bioinformatic analyses revealed that the differentially expressed genes were significantly associated with major histocompatibility complex I (MHC I)-mediated immunological processes, including immune system processes, antigen processing and presentation of exogenous peptide antigens via MHC class I, and interleukin-2 production. Importantly, molecular docking proposed a potential mechanistic model wherein BPB bound to estrogen receptor α (ERα) suppressed its testicular expression and triggered MHC class I gene overexpression, potentially promoting macrophage infiltration, CD4+/CD8+ T cell activation, and pro-inflammatory cytokine production. Our findings provide critical insights into the adverse effects of maternal BPB exposure on male reproductive development, suggesting that impairments in testicular morphology and spermatogenesis may be attributed to MHC I-mediated immunological responses and hormonal imbalances resulting from inhibited ERα signaling. These results underscore not only the toxicological risks associated with BPB but also potential therapeutic targets for mitigating male reproductive dysfunction.