Endocrine disruption and reproductive toxicity of polystyrene microplastics at environmentally relevant concentrations in Anabas testudineus

The prevalence of polystyrene microplastics (PS-MPs) in aquatic environments has raised significant concerns regarding their potential impact on the reproductive health of aquatic organisms. This study examined the effects of environmentally relevant concentrations of PS-MPs (13.6 mg/L and 23.6 mg/L) on the reproductive and endocrine functions of Anabas testudineus over exposure durations of 1, 7, 15, 30, and 60 days. In males, PS-MPs exposure resulted in a significant decline of sperm count, sperm viability, and motility, along with marked reduction in sperm DNA concentrations. In females, PS-MPs exhibited reduced fecundity and increased oocyte diameters. The activity of key steroidogenic enzymes significantly declined leading to altered serum levels of luteinizing hormone (LH), follicle stimulating hormone (FSH), testosterone, and estradiol, thereby disrupting the hypothalamic-pituitary-gonadal (HPG) axis. Notably, vitellogenin levels increased in males while decreasing in females, indicating pronounced sex-specific endocrine disruption. Histopathological analysis revealed substantial gonadal alterations where testes showed vacuolization, degeneration, and loss of spermatocytes, while ovarian tissues exhibited oocyte atresia and disorganization of follicular structures. The findings highlight the reproductive toxicity and xenoestrogenic potential of PS-MPs in fish, raising concerns about their chronic impact on fish reproductive fitness and population sustainability. The study underscores the urgent need for targeted research and mitigation strategies to address microplastics pollution in aquatic ecosystems.