The Effect of Cryopreservation on the Sperm Ultrastructure of Mus Musculus Albinus Strain DDY: Comparison of Nakagata vs Modified vs Kitazato Cryoprotectants

Introduction: Sperm morphology analysis is very necessary to understand male fertility and the etiology of infertility. Currently, scanning electron microscopy (SEM) has been widely used to determine surface topology. In this study, we will compare the effects of spermatozoa cryopreservation using three different types of cryoprotectants, namely Nakagata, modification and Kitazato. The cryoprotectant compositions used are Nakagata (raffinose and skim milk), modified (glycerol and raffinose) and Kitazato (glycerol and trehalose). Methods: SEM analysis was carried out on 8 sperm samples before cryopreservation and after the freeze-thaw process. Results: The results obtain showed that cryoprotectant modification was able to protect spermatozoa morphology better than Nakagata and Kitazato. Analysis revealed damage to plasma membrane, acrosome and loss of mitochondria in all treatment groups compared to fresh sperm. SEM showed obvious signs of post-thaw damage such as missing plasma membranes, sperm showing damaged acrosomes and mitochondria in the middle showing structural disorganization. Conclusion: SEM revealed that cryopreservation caused ultrastructural damage to mice sperm due to freezing and thawing. These details provide valuable data for further research to minimize the damage caused by cryopreservation to mice sperm. Apart from that, further examination using TEM is recommended to obtain a more comprehensive picture.