The aim of this study was to reveal the mechanism of enhanced ram sperm motility induced by heavy ion radiation (HIR) after in vitro liquid storage. Ram semen was stored for 24 hours at 5°C and then irradiated with 0.1 Gy carbon ion radiation (CIR). In comparison to nonirradiated (NIR) sperm, the motility, viability, and adenosine triphosphate content were all higher in CIR sperm, and the reactive oxygen species levels were lower. Moreover, 87 differential mitochondrial protein spots were detected in 2-dimensional gels between CIR and NIR sperm and were identified as 52 corresponding proteins. In addition, 33 differential proteins were involved in a main pathway network, including COX5B, ERAB/HSD17B10, ETFA, SDHB, and SOD2, which are known to be involved in cell communication, energy production, and antioxidant responses. We used immunoblotting and immunofluorescence to analyze the content and localization of these proteins, respectively, and the levels of these proteins in CIR sperm were lower than those in NIR sperm. An understanding of the molecular function of these proteins could provide further insight into the mechanisms underlying high sperm motility induced by HIR in rams.
Keywords: carbon ion radiation; mitochondria; proteomics; ram sperm.