In vitro maturation (IVM) of murine and human germinal vesicle (GV)–stage oocytes by coculture with immortalized human fallopian tube epithelial cells

Abstract

To improve the maturation rate of murine and human germinal vesicle (GV) oocytes using human tubal epithelial cells (hTECs). Murine and human GV oocytes were randomized to human tubal fluid (HTF) media alone or cocultured with mouse embryonic fibroblasts (MEFs) or primary hTECs or immortalized hTECS (ihTECs) for various times. Rates of maturation to meiosis II (MII) were compared between groups. TECs were isolated from discarded salpingectomy specimens. One batch was immortalized with TERT and SV40 large T-antigen. GV oocytes (n = 710) were isolated from 8-week-old-mice at 40 hours after pregnant mare's serum gonadotropin stimulation. Discarded human GV oocytes (n = 62) were obtained from intracytoplasmic sperm injection cycle IVF center patients. Oocytes were cultured in HTF media alone or with MEFs, hTECs, or ihTECs. Maturation rates were assessed by standard morphological criteria and compared. The maturation rate of murine GV oocytes to MII at 12 and 24 hours increased significantly in coculture with hTECS and ihTECS compared with MEF and HTF media alone. In addition, the development rate after IVF was significantly higher with hTECS and ihTECS than in MEF and HTF media alone. Maturation of human GV oocytes to MII at 24 and 48 hours was significantly higher in hTECS and ihTECS compared with HTF media alone. Coculture with either primary or immortalized TECs might improve oocyte quality and significantly raise in vitro maturation rates for GV oocytes.