Sperm Preparation by Washing and Swim-up Method Improves In Vitro Fertilization and Birth Rate in Mice

The method of preparing sperm supposedly affects the success rate of in vitro fertilization. This study aimed to investigate the effect of different sperm preparation methods on in vitro fertilization and birth rate in mice. Semen obtained from two C57bl6 and NMRI strains of mice were used for sperm preparation and in vitro fertilization. Sperm preparation was done using a directly add the sperms (G1), as density gradient centrifugation method (G2), along with swim-up of the pre-washed sperm method (G3). Two-cell embryos obtained from in vitro fertilization were then transferred into pseudopregnant mice. The quality of sperm, the rate of in vitro fertilization, and the birth rate were assessed in all three study groups. Significant differences were observed in motility between the control and swim-up (NMRI mice: P = 0.008 and C57 mice: P = 0.016) and the density gradient centrifugation (DGC) and swim-up (NMRI mice: P = 0.04 and C57 mice: P = 0.02) methods. Sperm concentration was significantly higher using the control method compared to the DGC (P = 0.002) and swim-up methods (P = 0.002) in both NMRI and C57 mice groups. Sperm viability in NMRI (87.7%) and C57 (80.6%) mice was significantly higher (P = 0.001) using the swim-up method compared to the other methods. The rates of in vitro fertilization and birth have significantly increased by the swim-up method. It can be concluded that the swim-up of pre-washed sperm as an efficient and inexpensive method can be considered as an alternative for the common method of preparing sperm for in vitro fertilization in mice.