Influences of cooling rate and interval agitation during cooling for cryopreservation in goat sperm

초록

Background: Sperm cooling is a critical step in cryopreservation, as exposure to temperatures below 15℃ can induce cold shock-associated damage, including phospholipid scrambling and lipid peroxidation. Goat sperm are particularly vulnerable to cooling-induced injury because of their membrane characteristics. This study evaluated the effects of cooling rate and interval agitation during cooling in frozenthawed goat sperm. Methods: The samples were cooled at 0.5℃/min (0.5 Cool) or 0.1℃/min (0.1 Cool) and agitated every 15 min during cooling until 5℃, then, the samples were cryopreserved in liquid nitrogen. After thawing, sperm motility was assessed using computer-assisted sperm analysis (CASA) and plasma membrane integrity, acrosomal integrity, intracellular H2O2 levels, mitochondrial activity, mitochondrial membrane integrity, and mitochondrial membrane potential (ΔΨm) were analyzed by flow cytometry. Results: In results, there were no significant differences in sperm motility, plasma membrane integrity, acrosomal integrity, and mitochondrial function among the treatment groups. However, intracellular H2O2 levels were significantly lower in agitation-treated groups than non-agitated groups both 0.5 Cool and 0.1 Cool treatment groups (p < 0.05), whereas there were no significant differences between cooling rate groups. Conclusions: In conclusion, these results indicate that interval agitation during the cooling process could reduce intracellular reactive oxygen species in frozen-thawed goat sperm.

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