Cumulus cell apoptosis changes with exposure to spermatozoa and pathologies involved in infertility

Abstract

To determine whether the incidence of apoptosis in mature oocyte cumulus cells changes after insemination related to infertility. Prospective study. Public hospital and university. One hundred women undergoing in vitro fertilization and embryo transfer (IVF-ET). Collection of cumulus cells from IVF-ET cycles with different infertility etiologies. Detection of apoptosis in cumulus cells; fertilization, embryo quality, and pregnancy rate. The incubation of cumulus-oocyte-complexes with spermatozoa led to an increase in cumulus cell apoptosis from 34.2 +/- 3.7 to 44.5 +/- 6.3%. After insemination, cumulus cells of poor quality embryos showed a statistically higher apoptotic rate versus cumulus cells of good quality embryos (61.5 +/- 6.4 vs. 40.6 +/- 3.9%). Cumulus cells arising from oocytes with >or=50% fertilization rates after insemination showed higher apoptosis rates did cumulus cells from oocytes with <50% fertilization rates (46.0 +/- 3.7 vs. 33.8 +/- 4.0%). Patients with endometriosis presented higher apoptotic rates before insemination (77.6 +/- 9.06%). Cumulus cells obtained after aspiration showed no differences in their apoptosis rates for the following factors: age of women, aspirated oocytes, estradiol level, fertilization rate, and embryo quality or pregnancy. The apoptotic profile from pregnant women was less than (but not statistically significantly different from) profiles from nonpregnant women. These results suggest that the incidence of apoptosis in cumulus cells is associated with exposure to spermatozoa and the cause of infertility.