Biochemical, Histological and Molecular Docking into the Impact of Polystyrene Nanoplastics on Antioxidant Enzymes and Testicular Health in Rats

Polystyrene nanoplastics (NPs) are widespread environmental pollutants that may pose health hazards. This study examined the impact of NPs exposure on antioxidant enzyme activity and testicular structure in rats. A total of 24 Rattus norvegicus (n=6) were allocated into four groups and administered varying NPs concentrations (0, 1, 2, and 4 µL/kg) via oral gavage for 35 days. After the exposure period, the rats were sacrificed to assess superoxide dismutase (SOD) and catalase (CAT) levels, as well as testicular histology. The findings indicated that NPs exposure did not significantly alter SOD levels but led to a significant decline in CAT levels at the highest concentration (4 µL/kg, p<0.05). Histological assessment showed reduced seminiferous tubule diameter and epithelial thickness, along with a significant reduction in spermatocyte and spermatid counts, indicating disruption in later stages of spermatogenesis. Complementary molecular docking analysis revealed that the polystyrene monomer had a stronger binding affinity for the catalase enzyme than for superoxide dismutase, supporting the observed reduction in CAT activity. These results highlight the potential adverse effects of NPs on reproductive health and raise concerns about human exposure risks.