EFFECTS OF UNCONJUGATED GOLD, SILVER AND TITANIUM DIOXIDE NANOPARTICLES ON BOVINE SPERMATOZOA AT VARIOUS STAGES OF CRYOPRESERVATION

BACKGROUND: The increasing use of nanoparticles (NP) for gender-selected spermatozoa, sperm -enriched semen and novel extenders raises the concern of undesirable effects on fertility and sperm function. OBJECTIVE: To investigate the effects of gold (Au-), silver (Ag-), and titanium dioxide (TiO2-) NPs on the motility and sperm functions in bovine spermatozoa at various stages of cryopreservation. MATERIALS AND METHODS: Frieswal (Sahiwal x Holstein Friesian) bull semen ejaculates (N = 24) were challenged with unconjugated and ligand-free Au-, Ag-, and TiO2-NPs. RESULTS: At post-dilution (fresh) stage, there was no significant difference observed in progressive motility and viability amongst the control and any nanoparticle-treated groups, though plasma membrane integrity was significantly reduced in nanoparticle-treated groups (p < 0.05). The acrosome intactness was also significantly reduced in the groups of Ag-NP and TiO2-NP (p < 0.05), while there was no effect observed in the Au-NP group. At post-equilibration stage, a significant reduction in motility, viability, and plasma membrane integrity was observed in all three nanoparticle-treated groups (p < 0.05). There was no difference in intact acrosome between the control and Au-NPs groups; which was significantly higher than the Ag-NP and TiO2-NP groups (p < 0.05). At post-thaw stage, all NP groups resulted in a significant reduction of motility, viability, acrosome intactness and plasma membrane integrity (p< 0.05). Besides, TiO2-NPs appear to be significant more toxic (p< 0.05) among three NP groups, and Au-NPs appear to be lesser toxic. CONCLUSION: Bovine spermatozoa are adversely affected by Au-, Ag-and TiO2-NPs that may impair sperm motility and other functions.