The potential protective roles of Astragalus polysaccharides against toxicity of polystyrene nanoplastics on mice sperm exposed.

INTRODUCTION

Polystyrene nanoparticles (PS-NPs) damage the male reproductive system, although the potential impacts on mammalian reproductive health remain unclear. The aim of this study was to determine the protective effect of Astragalus polysaccharides (APS) on testicular and epididymal functions in a mouse against PS-NPs as environmental pollutants.

METHODS

Male mice were randomly assigned to three groups (n = 6 each): control, PS-NPs at 50 mg/kg/day (P group), and PS-NPs at 50 mg/kg/day plus APS at 100 mg/kg/day (P+A group), aimed to elucidate the molecular mechanisms of PS-NPs exposure on sperm and the protective effects of APS. Testicular microstructure and function, serum testosterone level, enrichment of PS-NPs in the epididymis, sperm morphology and motility, concentration of zinc ions, the CuZn-superoxide dismutase activity (SOD) activity, total antioxidant capacity (T-AOC), malondialdehyde content (MDA) in seminal plasma, and protein tyrosine phosphorylation of non-/capacitated sperm were evaluated.

RESULTS

Exposure to PS-NPs significantly decreased the percentage of normal seminiferous tubules and serum testosterone levels (p < 0.05). The seminal plasma Zn2+ levels, CuZn-SOD activity, T-AOC, and sperm quality (density, motility, normal morphology) significantly reduced, with the increased the enrichment of PS-NPs in the epididymis and MDA levels of sperm on PS-NPs treatment group (p < 0.05). Exposure to PS-NPs induced the 32 ~ 35KDa protein tyrosine phosphorylation of non-capacitated sperm (p < 0.05). The protein tyrosine phosphorylation of capacitated sperm exposure by PS-NPs were decreased compare with control group (P < 0.05), which located in sperm flagella. After APS treatment, the functional impairments caused by PS-NPs were alleviated, and there was no significant difference in related indicators compared to the physiological group (p > 0.05).

DISCUSSION: APS relieved oxidative damage to sperm, enhanced antioxidant capacity, and protected against testicular and epididymal damage caused by exposure to PS-NPs. APS regulated protein tyrosine phosphorylation to prevented the of "capacitation-like" phenomenon of non-capacitated sperm caused by PS-NPs. Meanwhile, APS alleviated the decrease in proteins tyrosine phosphorylation of capacitated sperm exposed by PS-NPs. These results indicate that APS could be used to ameliorate sperm quality induced by environmental toxins.