Fortification of semen extender with mifepristone improves the cryo-survival of cattle spermatozoa.

Abstract

Background: Progesterone, which is present in the semen extender as a component of egg yolk is a potential inducer of capacitation in spermatozoa during cryopreservation. An anti-progesterone component in the extender may protect the spermatozoa from being capacitated and pre-acrosome reacted during cryopreservation. It may lead to better quality of post-thaw sperm population for improved conception.

Objective: To investigate the effect of mifepristone on the cryo-survivability of cattle spermatozoa.

Materials and methods: Thirty two semen ejaculates were collected from four Sahiwal bulls and divided into three fractions. These fractions were extended with egg yolk-based TRIS extender supplemented with different concentrations of mifepristone (0, 10 and 20 uM) and subjected to cryopreservation. Cryopreserved semen samples were thawed and evaluated for spermatozoa motion parameters (CASA), viability (flow cytometer), hypo-osmotic swelling test (HOST) responsiveness, capacitation status (CTC), acrosome reaction (flow cytometer) and intracellular calcium ion concentrations (flow cytometer).

Results: There was no definitive effect of mifepristone on sperm motility and kinematics. However, the semen samples which were treated with mifepristone showed significantly higher spermatozoa viability and HOST responsiveness. Mifepristone also protected spermatozoa from being cryo-capacitated during the preservation process. Higher percentages of uncapacitated and acrosome intact spermatozoa were found at the post-thaw stage in comparison to the untreated group. Mifepristone-treated groups showed fewer spermatozoa with high intracellular calcium levels.

Conclusion: A 10 uM concentration of mifepristone has better potential to protect the spermatozoa from progesterone-induced cryo-capacitation and premature acrosome reaction during cryopreservation. https://doi.org/10.54680/fr25210110612.