Heavy ion radiation can promote greater motility and enolase protein expression in ram sperm in in vitro liquid storage

The aim of the study was to determine the effects of heavy ion radiation (HIR) on ram sperm quality during 24 h of in vitro liquid storage at 15 °C, and identify the most appropriate dose which did not injure, but actually improved sperm quality and confirmed the relationship between highly expressed enolase and ram sperm quality during storage in vitro. Six Dorset ram (Ovis aries) semen pools from five mature and healthy rams were each divided into seven experimental groups with different doses of HIR (0, 0.05, 0.1, 0.2, 0.3, 0.4, and 0.5 Gy) under the same experimental conditions. Sperm motility, viability, ATP content, and the gene and protein expression of enolase were measured at 24 h of storage. Irradiated semen which had been stored for 24 h, retained not only greater sperm motility, viability, and ATP content, but had greater enolase protein expression. This was evidenced by increased amounts of mRNA for this enzyme and amount of enolase protein as compared with semen from control rams, especially for the 0.1 Gy group (P < 0.001). These results indicate that HIR can promote enhanced motility and viability during in vitro liquid storage, and the 0.1 Gy may be a suitable dose for improving sperm quality. Greater amounts of enolase and ATP content may results from enhanced sperm glycolysis by HIR. HIR enhances sperm glycolysis to generate sufficient ATP for maintaining sperm motility during storage.