Caspase Gene Expression Profiles Of Different Pig Sperm Cryopreservation Diluent

Artificial insemination has been widely used in modern pig breeding industry. However, almost all of swines were inseminated with extended and liquid boar semen, AI with cryopreservation or frozen-thawed semen was limited to no more than1%of total inseminations. Studies show that there are about20-30%conception and farrowing rates and2-3total litter size lower than those achieved by fresh semen. Although substantial progress has been made towards boar semen cryopreservation, cryopreservation conditions are still considered to be suboptimal, and antifreeze mechanism of boar spermatozoa remains unknown. The present paper investigated all of15caspases expression on boar spermatozoa during cryopreservation, and compare the pattern of caspase expression on different CPAs based on LEY (Lactose-Egg Yolk) extender. The results as follows:(1) There are no significant differences between three main cryoprptectants glycerol, DMSO and ethylene glycol on the caspase expression during boar cryopreservation. Compare with DMSO and glecerol, ethylene glycol added in the Lactose-Egg Yolk extender can inhibit the expression of caspase-1.(2) Compare to the results of direct freezing, Lactose-Egg Yolk extender contains lactose can effectively inhibit the expression of Caspase-1,-2and-15; However, the trehalose group can only prevent the caspase-1from expression of boar cryopreservation. At the same time, the LEY extender with glucose can only inhibit the caspase-15expression. Therefore, the LEY extender with lactose is more effecient than trehalose and glucose to protect the boar spermatozoa from cryoinjury. There are no significant differences between trehalose and glucose on expression of caspase during boar cryopreservation.(3) Superoxide dismutase (SOD) was the most effective inhibitor to caspase expression among three antioxidants, and glutathione was the worst one. Although SOD and catalase were failed to prevent initiator caspases from expression, they can effectively inhibit the expression of downstream caspases. (4)Direct freezing has no any effects on expression of excutive caspases,such as capase-3,-7ana-9.