Matrix metalloproteinase (MMP)-2, MMP-9, semen quality and sperm longevity in fractionated stallion semen.

This research studied the impact of certain enzymes, specifically MMP-2 and MMP-9 on horse semen quality and sperm survival during storage. The results indicate that while these enzymes are present in all fractions of ejaculate, their activities do not serve as useful markers for semen quality or sperm longevity during storage.

Introduction

• The study executed an investigation into the roles of Matrix metalloproteinase (MMP)-2 and MMP-9, referred to as gelatinases, in stallion’s reproductive processes. Gelatinases are enzymes that degrade the extracellular matrix, participating in various biological processes.
• The investigation’s purpose was to discern if these metalloproteinases could serve as meaningful indicators for the quality of semen and sperm longevity during cooled storage.

Methodology

• The researchers performed quality assessments on different fractions of stallion semen for 33 stallions: sperm-rich, sperm-poor, and whole samples.
• Semen was stored and observed under two conditions: with seminal plasma (a component of semen also referred to as SP) present or removed.
• Sperm motility (movement capability) and DNA Fragmentation Index (DFI- indicates DNA damage) were determined post storage.
• Gelatin zymography was utilized to evaluate the activities of MMP-2 and MMP-9 in the semen.

Results

• The results of the study found that both MMP-2 and MMP-9 were present in all fractions of the horse’s ejaculate. The enzymes were more active in the latent form and in the sperm-rich fraction.
• Positive correlations were established between MMP-2, and MMP-9 activities and sperm concentration and total sperm count, especially in the sperm-rich fraction. However, this correlation was not observed in the low sperm count fraction or the whole ejaculate samples.

Conclusion

• The activities of MMPs did not demonstrate a relationship with sperm survival during storage, regardless of them being gauged by sperm motility or DFI.
• The researchers concluded that the activities of MMP-2 and MMP-9 in the semen are not insightful as markers for semen quality, except for sperm concentration, or sperm longevity during storage in horses.