Study on the application of zona pellucida to the preservation of sperm in the second-generation in vitro fertilization

SU Zhanying; ZHANG Qin; GU Min; WU Chengliang

Abstract：Objective:To explore the effect of cryopreservation of microsperm by egg zona in the second generation of in vitro fertilization pregnancy.Methods:The data of 40 couples who received testicular biopsy to assist pregnancy from June 2019 to October 2023 were retrospectively analyzed,and they were divided into group A(40 cycles)and group B(25 cycles)according to whether or not the biopsied sperm were frozen through the oocyte zonalis.Group A was assisted by fresh testicular punctured sperm,group B was assisted by cryopreservation of resuscitated sperm with ovum pellucidum.Among them,25 couples received two assisted pregnancies(fresh testicular sperm and frozen resusci-tated sperm were used for 1 cycle each).Laboratory indicators[percentage of mature oocytes(MII egg rate),percent-age of two prokaryotic embryo fertilization(2PN fertilization rate),the percentage of embryos with two prokaryotes and cleavage(2PN ovulation rate),percentage of good quality embryos at cleavage stage(D3 excellent embryo rate)]were compared between the two groups.Meanwhile,25 couples who had received two assisted pregnancies were divided into fresh testicular sperm and thawed sperm,and the differences of laboratory indicators between the two parts were compared.Results:There was no statistical significance in MII egg rate,2PN fertilization rate,2PN cleavage rate,D3 fine embryo rate,blastocyst formation rate and clinical pregnancy rate between the two groups(P＞0.05).There was no statistical significance in laboratory indicators of the same couple receiving two kinds of sperm from different sources for assisted pregnancy(P＞0.05).Conclusion:Cryopreservation of microsperm with zona pellucida can achieve similar clinical outcomes in azoospermic patients without fresh testicular sperm,at the same time to reduce the pain and trauma of repeated testicular biopsy in men,this method to ensure that a small amount of sperm in the freezing-resuscitation process will not be lost,this method is easy to obtain high-quality thawed sperm.