Basic fibroblast growth factor expression in isolated small human ovarian follicles

Basic fibroblast growth factor (bFGF) is involved in cell proliferation, differentiation, and angiogenesis. It has long been known that bFGF acts as a powerful mitogen for various mammalian granulosa cells in culture. To investigate the possible involvement of bFGF expression in follicle initiation and growth in vivo, we performed nested RT-PCR on ovarian cortical biopsies and quantitative PCR on human follicle populations isolated by laser capture microdissection. Using morphological criteria, follicles were characterized as putative non-growing, primary, or small secondary. RNA was extracted from samples, reverse-transcribed, and relative gene expression levels determined with TaqMan real-time PCR, using 18S rRNA as the endogenous control. Results confirmed bFGF expression in human adult ovarian cortex, and in the isolated follicles a down-regulation of bFGF mRNA was evident as small follicles develop. This study demonstrates a possible relationship between bFGF mRNA expression and follicle development.