P-502: Relationship of the CD9 protein on human granulosa cells and platelets with fertilization rates in women undergoing in vitro fertilization (IVF)

Abstract

CD9 is a cell surface protein that plays a crucial role in sperm-oocyte fusion and fertility in female mice. We tested whether CD9 expression on granulosa cells and platelets was correlated with fertilization rates in women undergoing in vitro fertilization (IVF). Prospective, observational study of women undergoing IVF. Women undergoing IVF for female infertility were asked for informed consent to participate in this study if their oocytes were to be fertilized by the conventional method. Each study subject demonstrated positive ovulatory function, normal ovarian reserve, and a normal semen analysis from the male partner. Granulosa cells and platelets were collected on the day of oocyte retrieval and isolated using previously published techniques. Granulosa cell and platelet surface density of CD9, and the percent of granulosa cells expressing CD9, were measured using flow cytometry. These values were compared to fertilization rates per subject, measured as the percent of oocytes that progressed to the two pronuclei/two polar body stage (2PN/2PB) following conventional fertilization. Thirty women participated in this study, with fertilization rates ranging from about 25% to 80%. Among all patients, the number of granulosa cells expressing CD9 ranged from about 30% to 90%. Fertilization rate was weakly associated with surface density of CD9 on granulosa cells, although there was no significant relationship between fertilization rate and the percent of granulosa cells expressing CD9 (R<0.1, P>0.05). There was also no significant relationship between fertilization rate and cell surface density of CD9 on platelets (R<0.1, P>0.05). The intensity of CD9 expression in granulosa cells may be related to fertilization rates in women undergoing IVF. Our data suggest that the number of granulosa cells expressing CD9 and platelet expression of CD9 would not be useful indicators of fertilization in oocytes from patients undergoing IVF.