P-12: Effect of Centrifugation on Levels of Stress Oxidative of Human Spermatozoa

Background: Cryopreservation has adverse effect on human spermatozoa via exposure to physical and chemical stress that may lead to alter in reactive oxygen species (ROS) levels. During sperm preparation or cryopreservation, centrifugation as a physical stress may effect on sperm quality probably with stress oxidative production and membrane damage. Therefore the aim of this study was to evaluate the effects of centrifugation on stress oxidative level before and after cryopreservation. Materials and Methods: This study was performed on 23 semen samples that were considered normal according to the world health organization (WHO) criteria. Fresh and frozen-thawed semen sample were divided into two equal portions. One portion was directly used for assessment of stress oxidative and named unwashed, while the other fraction was washed and labeled as washed group. Percentage of ROS-positive sperm were evaluated by H2DCFDA (2', 7'-dichlorodihydrofluorescein diacetate) probe. Results: ROS-positive sperm were significantly higher in the washed groups compared to the unwashed groups before freezing (71.51 ± 3.68 vs. 61.66 ± 4.40, p=0.00) and following freezing (58.01 ± 4.65, vs. 45.99 ± 4.40, p=0.00). Conclusion: The results of this study revealed that centrifugation increase the percentage of ROS-positive sperm. These increase probably due to centrifugations force, removing antioxidants from semen plasma during the washing process or alter in membrane structure sperm.