The purpose of this study was to assess the effect of different concentrations of zinc oxide nanoparticles (ZnONPs) introduced to an extender for frozen-thawed epididymal dog spermatozoa. Epididymides from 22 castrated dogs were minced and cultured in a Tris buffer. The recovered spermatozoa were diluted in Tris-Citric acid-Fructose (TCF) extender with different concentrations of ZnONPs (100 and 200 µg/mL) and control (0.0 µg/mL). Diluted samples were equilibrated at 5 °C for 2 hours before being packed in 0.25 mL straws and stored in liquid nitrogen (-196 °C). After thawing at 37°C for 30 seconds, sperm motility, viability, membrane integrity, acrosome integrity, DNA integrity, and lipid peroxidation by malondialdehyde (MDA) concentration were all measured. The results were presented as mean ± SEM. Adding 100 and 200 µg/mL ZnONPs to the cryopreservation medium significantly (P < .05) improved motility and membrane integrity compared to the control. Viability and acrosome integrity were considerably (P < .05) better at 100 µg/mL ZnONPs than at 200 µg/mL ZnONPs and the control. MDA concentration was significantly (P < .05) decreased at 100 µg/mL ZnONPs compared to 200 µg/mL ZnONPs and the control. When 100 µg/mL ZnONPs were compared to 200 µg/mL ZnONPs and the control, the percentage of DNA damage was significantly (P < .05) reduced. Consequently, adding 100 µg/mL ZnONPs to TCF extender resulted in a significant increase in the proportion of motility, viability, membrane-intact, and acrosome-intact dog epididymal sperm, as well as the preservation of DNA integrity and the prevention of lipid peroxidation at the membrane level.
Keywords: cryopreservation; dog; epididymal sperm; oxidative stress; zinc oxide nanoparticles.
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