Effect of Polyvinyl Alcohol on The Motility, Morphol-ogy and Viability of Human Sperm after Thawing

Background: Sperm cryopreservation has been used widely since the 1970s to store sperm in patients undergoing cancer therapy and play a vital role in treating couples with infertility. However, Cryopreservation lead to induce different in cellular organelles which result in reduction of sperm quality. Cryopro-tective agents can minimize cryopreservation injury. Small con-centrations of the synthetic polymer polyvinyl alcohol (PVA) were found to inhibit the formation of ice during cryopreser-vation. PVA clearly shows potent ice recrystallization inhibi-tion (IRI) activity with arrest of ice crystal growth similar to antifreeze proteins. Therefore, the purpose of this study was to evaluate the cryoprotective effects of PVA on human sperm during cryopreservation process.Materials and Methods: Semen samples were collected from twenty normospermic men and divided into two equal parts to be diluted with two concentrations of (0.01 % and control). Semen samples were diluted with a glycerol egg yolk citrate (GEYC) based freezing medium. Then diluted semen was cooled and packed into straws. The straws were frozen in steam of liquid nitrogen (LN2) and then preserved in the LN2 and stored until thawed and used for evaluation. After thawing, mo-tility, viability and morphology of thawed sperm were assessed.Results: Results showed that 0.01 % PVA improved the per-centage of total motility, progressive motility and viability of human compare to control samples. Morphology was not af-fected by adding PVA to freezing media.Conclusion: It can be concluded that supplementation of freez-ing media with PVA at concentration of 0.01%, can increase the efficiency of cryopreservation of human sperm.