Protective effect of epigallocatechin-gallate in cryopreserved goat sperm on post-thawed quality

Cryopreservation is a useful technique for preserving goat sperm, but it often causes damage due to oxidative stress triggered by increased reactive oxygen species. One promising solution is the use of antioxidants, such as epigallocatechin gallate (EGCG), to reduce these harmful effects. EGCG has been recognised for its ability to safeguard sperm cells by supporting the normal function of mitochondria, regulating cell death mechanisms, and supporting genes involved in energy metabolism.

This study aimed to evaluate the effects of different concentrations of EGCG added to semen extenders on the quality of goat sperm after thawing, including motility, viability, and the expression of genes related to mitochondrial activity and apoptosis.

Several concentrations of EGCG (ranging from 50-800 mg/dl) were tested. Post-thaw sperm motility and viability were analysed using Open CASA^®. B-cell lymphoma-2 (BCL-2) expression was observed using immunocytochemistry, while CPT2 gene expression was assessed by Reverse Transcription Quantitative Polymerase Chain Reaction. Statistical analyses were conducted using Duncan's and Kruskal-Wallis tests, followed by pairwise comparisons.

The findings showed that 200 mg/dl of EGCG significantly improved sperm motility, while the 100 mg/dl dose helped maintain better viability after thawing. Interestingly, BCL-2 expression increased most notably at 500 mg/dl, indicating anti-apoptotic protection. Additionally, CPT2 gene expression was significantly upregulated at EGCG concentrations of 50, 100, 400, and 800 mg/dl compared to the control group.

EGCG supplementation in goat semen extenders has a protective effect on post-thawed sperm by improving motility and viability and supporting mitochondrial and apoptotic pathways. These results suggest that EGCG can be a valuable additive for enhancing artificial insemination outcomes in goats.