Selected Metabolites Found in Equine Oviductal Fluid do not Modify the Parameters Associated to Capacitation of the Frozen-thawed Equine Spermatozoa In Vitro.

This study aimed to investigate if specific metabolites found in horse oviductal fluid influenced the quality parameters of frozen-thawed horse sperm. The researchers concluded that the addition of these metabolites had no discernible impact on the analyzed sperm parameters.

Objective of the Study

• The goal of the study was to test the effects of various metabolites found in equine oviductal fluid on the quality parameters of frozen-thawed horse spermatozoa. This was underpinned by the fact that a repeatable protocol for in vitro fertilization has not been set up in horses, potentially due to incomplete sperm capacitation.

Metabolites and Methodology

• Several metabolites were taken into consideration for this experiment, including myoinositol, lactate, glycine, β-alanine, and histamine. Each of these was added independently to a solution known as modified Whitten’s medium at different concentrations.
• The sperm of three stallions was thawed and then incubated for two hours at 37˚C in the presence of these chosen metabolites.

Analysis of Sperm Parameters

• Following sperm incubation, various parameters were evaluated to assess the impact of the metabolites. These involved total motility (TM), progressive motility (PM), viability (SYBR-14/PI), mitochondrial membrane potential (ΔΨm) (JC-1), an acrosome reaction (PNA/PI), reactive oxygen species (ROS) production (CellRox/PI), and protein tyrosine phosphorylation (PY). These evaluations were conducted through computer-assisted sperm analysis, flow cytometry, and indirect immunofluorescence.

Results and Conclusions

• The conclusion drawn from the study was that the introduction of the tested metabolites did not influence the measured sperm criteria in any notable manner.
• The authors suggest that future research should test whether adding metabolites at the dosages found in the equine oviductal fluid would have any impact on equine sperm capacitation in vitro.