Defects in phospholipase C zeta cause polyspermy and low fertilization after conventional IVF:not just ICSI failure

Phospholipase C zeta(PLC)is a key sperm-borne oocyte-activating factor that triggers Ca^(2+)oscillations and the subsequent block to polyspermy following gamete fusion.Mutations in PLCZ1,the gene encoding PLCζ,cause male infertility and intracytoplasmic sperm injection(ICSI)fertilization failure;and PLCζ expression and localization patterns are significantly correlated with ICSI fertilization rate(FR).However,in conventional in vitro fertilization(cIVF),whether and how sperm PLCζ affects fertilization remain unclear.Herein,we identified one previously reported and two novel PLCZ1 mutations associated with polyspermy in vitro that are characterized by excessive sperm-zona binding and a delay in pronuclei(PN)formation.Immunofluorescence staining and oocyte activation testing revealed that virtually all spermatozoa from patients lacked functional PLCζ and were thus unable to evoke Ca^(2+) oscillations.ICSI with an artificial oocyte activation treatment successfully rescued the polyspermic phenotype and resulted in a live birth.Furthermore,we analyzed PLCζ in an additional 58 males after cIVF treatment in the Reproductive and Genetic Hospital of CiTiC-Xiangya(Changsha,China)between February 2019 and January 2022.We found that the proportion of spermatozoa that expressed PLCζ was positively correlated with both 2PN rate and total FR.The optimal cutoff value below which males were likely to experience low FR(total FR≤30%)after clVF was 56.7%for the proportion of spermatozoa expressing PLC5.Our study expands the mutation and the phenotypic spectrum of PLCZ1 and further suggests that PLCζ constitutes a promising biomarker for identifying low FRs cases in cIVF due to sperm-related oocyte activation deficiency and that sperm PLCζ analysis may benefit the widermale population and not onlymen with IcsI failure.

Study of the Sperm Chromosomal Aneuploidies of Isolated Teratozoospermic Men

Objective To determine whether patients with isolated teratozoospermia have increased or decreased incidence of chromosomal aneuploidies. Methods Sperm obtained from isolated teratozoospermic men （teratozoospermic group, n=18） and normal fertile men （the control, n=5） were analyzed using FISH （for chromosomes 18, X and Y）. Results A total of 58 178 spermatozoa were counted from the teratozoospermia group and 16 369 spermatozoa were counted from the control, with the hybridization rates of 97.5% and 98.3%, respectively. The major types of chromosomal aneuploidies were disomy （YY18, XX18, XY18, Y1818 and 3（1818） and diploidy （1818XX, 1818YY, 1818XY）. In the teratozoospermic group and the control, the disomy rates of 18 chromosome were 0.29 ±0.16% and 0.03 ±0.02%, the disomy rates of sex chromo- some were 0.65 ±0.24% and 0.05 ± 0.02%, the diploidy rates were 0.14 ± 0.12% and 0. 04±0.03%, respectively..411 the differences between these two groups were significant （P〈0. 05）.Conclusion Sperm of isolated teratozoospermic men have higher rates of 18, X and Y chromosomal aneuploidies than that of the fertile controls.