Improving sperm cryopreservation with type III antifreeze proteins: effect on proteomic profiles of Cynomolgus macaque sperm

Antifreeze protein III (AFP III) has been used in the cryopreservation of germ cells in several kinds of animals, but it is not yet known what the specific cryoprotective mechanism of AFP III is, except for reducing the formation of ice crystals during cryopreservation. In order to study the cryoprotective mechanism of AFP III on sperm cryopreservation, the proteomic profile of Cynomolgus macaques sperm were identified after cryopreservation. Compared to fresh sperm, 141 and 32 proteins were differentially identified in Cynomolgus macaques sperm cryopreserved without and with 0.1µg/ml AFP III, respectively. These proteins were mainly involved in mitochondrial production of reactive oxygen species (ROS), glutathione (GSH) synthesis and cell apoptosis. According to the differential proteins, we supposed that AFP Ⅲ mainly reduce sperm lipid, protein and DNA damage, as well as the release of cytochrome c, and thereby reduce sperm apoptosis by modulating the production of ROS in mitochondria. The molecular mechanism that how AFP III acts with sperm proteins and protects cell from cryoinjuries needs further study.