Effects of follicle-stimulating hormone and serum substitution on the in-vitro growth of human ovarian follicles

In-vitro maturation (IVM) of human ovarian follicles and oocytes could bene fit infertile women, and allow the development of in-vitro systems for the study of human follicular development. Little is known about the initiation of growth of primordial follicles and the regulation of early folliculogen esis. An ovarian tissue-slice culture system was used to examine the effect s of media composition, follicle stimulating hormone (FSH) and serum substi tution on the development of small human follicles in vitro. Human ovarian cortex biopsies were cut into small pieces and cultured for 5, 10 or 15 day s. Control (non-cultured) and cultured tissue was fixed, serially sectioned , and stained. The follicles contained within the tissue pieces were counte d, measured, and assessed for stage of development and viability. Compariso n of the ability of alpha-minimum essential medium (alpha-MEM), Waymouth's, or Earle's balanced salt solution (EBSS) culture media (all with 10% human serum) to support follicle growth demonstrated significantly increased ini tiation and growth of follicles in alpha-MEM during the first 10 days of cu lture. The supplementation of alpha-MEM with 300 mIU/ml FSH significantly r educed levels of atresia and increased the mean diameter of healthy follicl es. Follicles in tissue cultured for 10 days with human serum albumin and I TS (insulin/transferrin/selenium mix) were significantly larger, more devel oped and showed significantly less atresia than those cultured with serum a lone. Primordial to small preantral follicles can be grown under serum-subs tituted conditions in tissue-slice culture, and are responsive to FSH, whic h is thought to be acting mainly as a survival factor at these early stages .