Effects of different concentrations of zinc oxide nanoparticles on the quality of ram cauda epididymal spermatozoa during storage at 4°C.

Zinc oxide nanoparticles (ZnO-NPs) are known for their antioxidant effects. In this study, ZnO-NPs were synthesized using aqueous extract of Maclura pomifera fruit; then, their effects on the quality of ram cauda epididymal spermatozoa were evaluated during storage at 4°C. ZnO-NPs formation was characterized by ultraviolet-visible spectroscopy (UV-vis), energy dispersive spectroscopy (EDX), field emission scanning electron microscopes (FE-SEM) and Fourier transform infrared (FTIR) spectroscopy. Cytotoxicity responses were investigated by 3-[4,5-dimethylthiazole-2-yl]-2,5-diphenyltetrazolium bromide (MTT). Cauda epididymal spermatozoa were obtained from testicles collected from abattoir(s). The sperm samples were pooled. The samples were diluted by extender and supplemented with different concentrations of ZnO-NPs (0, 1, 5 and 25 µg/ml) and cooled to 4°C for 72 hr. Total motility, viability, DNA and membrane integrity, morphological abnormality, malondialdehyde (MDA) and antioxidant activities: superoxide dismutase (SOD) and total antioxidant capacity (TAC) of cooled diluted samples were evaluated. Addition of 1 μg/ml of ZnO-NPs increased sperm viability under normal conditions (p < .05). Extender supplementation with 1 μg/ml of ZnO-NPs improved sperm total motility, viability, DNA and membrane integrity during storage periods (p < .05). Moreover, using 1 μg/ml of ZnO-NPs improved (p < .05) MDA, TAC and SOD activities after 72 hr compared to other treatments. In conclusion, there were some beneficial effects of ZnO-NPs supplementation in ram epididymal sperm extender during oxidative stress conditions and cooled storage.