Benzo[a]pyrene lowers the sperm quality in male rats by downregulating the expression of ZMYND15 and ZMYND10.

This study investigated the impact of benzo[a]pyrene (BaP) exposure on male reproductive health, revealing a dose-dependent decline in sperm count, density, and serum testosterone levels. BaP exposure significantly impaired sperm motility, as evidenced by reduced kinematic parameters (VSL, VCL, VAP, LIN, STR, WOB). Molecular analysis demonstrated that BaP downregulated the expression of key genes, including ZMYND10 and its associated motility protein DNALI1, and the spermiogenesis regulator ZMYND15 along with its downstream targets (DPY19L2, AKAP4, AKAP3, SPEM1, PRM1, CATSPER3). These alterations in gene expression are linked to structural and functional deficits in sperm, such as abnormal morphology (coiled tails, folded heads) and impaired flagellar development. Our research infers that Bap diminishes sperm quality in male rats and induces reproductive harm by downregulating ZMYND15 and ZMYND10, hence influencing the expression of their associated genes. This study elucidates a novel mechanism for BaP-induced impairment of sperm quality.