Cholesterol-loaded-cyclodextrins improve the post-thaw quality of stallion sperm.

This research studied the effect of adding cholesterol to stallion sperm before freezing, with findings indicating that this method improved the survivability and quality of the sperm after thawing.

Introduction

The research article discusses an identified problem in the reproductive field, specifically concerning the preservation of stallion sperm. A significant proportion of stallion sperm does not survive the process of freezing and thawing, which is a common method for sperm preservation. Therefore, the researchers sought to improve the viability and quality of the sperm post-thaw by introducing cholesterol into the semen extender used during the freezing process.

Hypothesis and Methodology

• The hypothesis of the researchers was that adding cholesterol would stabilise the sperm membrane and increase its survivability and quality after thawing.
• To test this hypothesis, semen was collected from three stallions and diluted in four different extenders, including TALP; TALP with additional cholesterol; and Equipro.
• The samples were then incubated, centrifuged, diluted, and frozen in straws and stored in liquid nitrogen for preservation or”cryopreservation”.
• The researchers assessed each treatment method for progressive linear motility (PLM), membrane integrity under hypotonic conditions, viability, membrane fluidity, and superoxide generation.

Results

• The results showed that the treatments with added cholesterol (MβCD1.5 and MβCD0.75) had a greater proportion of viable sperm than the TALP treatment.
• However, the treatment method did not affect the PLM or membrane integrity of the sperm.
• A larger proportion of sperm treated with MβCD1.5 showed positive for membrane fluidity compared to the TALP treatment, indicating an increase in the quality of the sperm.
• Futhermore, the MβCD1.5 and MβCD0.75 treatments had lesser proportions of viable sperm positive for superoxide generation than the TALP treatment, suggesting a reduction in the cellular stress of the sperm.

Conclusion

These findings suggest that adding cholesterol to the semen extender used in the freezing process of stallion sperm may improve the viability and quality of the sperm after thawing. The enhanced survivability is likely due to the stabilising effect of cholesterol on the sperm membrane. Moreover, the viable sperm showed better quality in terms of increased membrane fluidity and reduced superoxide generation, which implies lower cellular stress. The results could contribute to advancements in the preservation methods of stallion sperm and might enhance the success rates of artificial insemination in equines.