Toxicity to the Male Reproductive System after Exposure to Polystyrene Nanoplastics: A Macrogenomic and Metabolomic Analysis

Nanoplastics (NPs) cause serious contamination of drinking water and potential damage to human health. This study aimed to investigate the effects of NPs with different particle sizes and concentrations on the reproductive function of male mice. In this study, free drinking water exposure was used to expose male BALB/C mice to PS-NPs (20 nm, 200 nm, and 1000 nm) at 0.1 mg/L, 1 mg/L, and 5 mg/L for 4 months. The male reproductive function of the mice was assessed after NPs exposure, and fecal and blood samples were collected for macrogenomics and metabolomics. The results showed that PS-NPs resulted in mice with reduced testicular organ coefficients, decreased sperm quality, altered testicular tissue structure, disturbed sex hormone levels, and abnormal levels of inflammatory factors and oxidative stress. Furthermore, this study found that NP exposure affected the alteration of gut communities and metabolic pathways related to male reproduction, such as Clostridium and glutathione metabolism. Importantly, we found an effect of NP particle size on reproductive function. In the future, more attention should be paid to the smaller particle sizes of NPs.