Study on the reproductive toxicity of co-exposure to lead and microplastics at environmental concentrations in zebrafish

This study aimed to assess the reproductive toxicity of co-exposure to environmental concentrations of lead (Pb) and polyethylene microplastics (PE-MPs) in zebrafish, providing a theoretical basis for evaluating the ecotoxicity and reproductive health risk of combined Pb and PE-MPs exposure at environmental concentrations. Wild-type AB strain zebrafish were divided into four groups: blank control (Ctrl), Pb exposure (Pb), PE-MPs exposure (PE-MPs), and Pb+PE-MPs co-exposure (Pb+PE-MPs). Each group contained 30 adult fish (1:1 sex ratio) and was exposed for 30 days. Results indicated that co-exposure to Pb and PE-MPs at environmental concentrations induce hormonal imbalance, oxidative stress dysregulation, altered inflammation levels, and reproductive suppression in the gonadal tissues of zebrafish. This subsequently impaired the survival and development of F1 offspring, with pronounced sex-specific heterogeneity. Reproductive damage in both male and female zebrafish was associated with endoplasmic reticulum stress and DNA damage. Notably, male individuals exhibited lipid metabolism disorders and abnormal activation of mitochondrial autophagy and ferroptosis pathways, whereas females primarily showed disturbances in metabolic pathways involving amino acid synthesis and degradation. Collectively, co-exposure to environmentally relevant concentrations of Pb and PE-MPs induced sex-dependent reproductive toxicity. These findings offer novel insights into the reproductive toxicity and ecotoxicological risk of combined Pb and PE-MPs exposure.