Cryoprotective Effect of Zinc and Gold Nanoparticles During Cooling and Freeze-thawing on Marwari Stallion Sperm Parameters and Reactive Oxygen Species Production

Abstract

BACKGROUND: Sperm cryopreservation is one of the most important procedures in the development of biotechnologies for assisted reproduction. Cryopreservation of stallion spermatozoa tends to cause plasma membrane damage due to the low ratio of cholesterol to phospholipids. Different substances and compounds can be added to semen extenders to improve sperm quality. OBJECTIVE: To investigate the effect of supplementing semen extender with zinc nanoparticles (ZnONPs) and gold nanoparticles (AuNPs) on cooled and frozen-thawed spermatozoa of Marwari stallion. MATERIALS AND METHODS: A total of 20 ejaculates from four Marwari stallions (five ejaculates from each) were collected. The gel free semen was extended with primary extender in equal volume and then divided in three equal groups, namely control (C), zinc (ZnO) and gold (Au), and centrifuged to obtain a final concentration of 100-150 x10 6 mL -1 and then cryopreserved. Cooled and post-thaw semen evaluations were conducted for various seminal characteristics, viz. progressive sperm motility, sperm plasma membrane integrity, sperm viability, acrosome integrity and mitochondrial membrane potential. RESULTS: Cooled semen (4ºC for 2 h) evaluation revealed nonsignificant differences among the groups (C, ZnO and Au) for all the semen quality parameters. However, at the post-thaw stage, progressive sperm motility, sperm plasma membrane integrity, acrosome integrity and oxidative parameters were significantly (P≤ 0.01) higher in the ZnO group than Au and C. CONCLUSION: The addition of ZnO nanoparticles improves the post thaw quality of stallion spermatozoa by reducing the oxidative stress, but Au nanoparticles had no effect on cooled as well as post-thaw semen quality.