Correlation Between Dissolved Oxygen Level, Antioxidants and Oxidants in Semen Diluted with Partially Deoxygenated Extender at Various Stages of Cryopreservation

BACKGROUND: Dissolved oxygen (DO) in semen dilutor may lead to the production of reactive oxygen species (ROS) and buffalo sperm may become more prone to deleterious effects of ROS due to the presence of high amounts of polyunsaturated fatty acids (PUFAs) in their membranes. OBJECTIVE: To study the correlation between dissolved oxygen level, antioxidants and oxidants in semen diluted with partially deoxygenated extender at various stages of cryopreservation. MATERIALS AND METHODS: Each semen sample was split into two aliquots viz., Aliquot I [diluted with Extender I (control: without deoxygenation)] and Aliquot II [diluted with Extender II: partially deoxygenated by liquid nitrogen (LN) flushing], which were diluted, filled in straws, cryopreserved and evaluated post-thaw. RESULTS: The DO levels ( P < 0.05) decreased significantly after LN flushing of the extender and they increased significantly ( P < 0.05) in post-thaw semen. The progressive motility, viability, hypo-osmotic swelling response, acrosomal integrity, glutathione peroxidase (GPx), total antioxidant capacity (TAC) and superoxide dismutase (SOD) decreased significantly ( P < 0.05) in both control and treated semen after thawing. SOD and TAC were positively correlated in semen treated with normal extender at the pre-freeze stage; however, in semen treated with partially deoxygenated extender, no correlation was found between SOD and TAC at the pre-freeze stage. ROS and total TAC were negatively correlated in semen treated with partially deoxygenated extender at the pre-freeze stage; however, no correlation was found between ROS and TAC in control semen. CONCLUSION: The partial deoxygenation of extender affects the correlation between sperm quality parameters, antioxidants, and oxidants during different stages of semen cryopreservation.