The combination of basic fibroblast growth factor and kit ligand promotes the proliferation, activity and steroidogenesis of granulosa cells during human ovarian cortical culture

Abstract

Different factors, such as basic fibroblast growth factor (bFGF) and kit ligand (KL), are used in ovarian cortical culture to promote activation of primordial follicles. In the present study, the effects of bFGF and KL, alone and in combination, were evaluated on human follicular activation and growth during in-situ cortical culture. Slow frozen-thawed human ovarian cortical tissues (n = 6) were cultured in 4 different groups: 1) control (base medium), 2) KL (base medium; BM + 100 ng/ml KL), 3) bFGF (BM + 100 ng/ml bFGF) and 4) bFGF + KL (BM + 100 ng/ml KL + 100 ng/ml bFGF) for a week. The proportion of morphologically normal and degenerated follicles at different developmental stages, secreted hormonal levels and specific gene expressions were compared. Although the proportion of growing follicles was higher than primordial counterpart in all cultured groups, no significant differences were observed among the cultured groups. In all cultured groups, anti-Müllerian hormone (AMH), progesterone and estradiol hormones levels increased after 7 days of culture; however, this increase was only significant for estradiol in the bFGF + KL group. The expression of Ki67 gene indicated an increase in ovarian cell proliferation in the three experimental groups compared to the control group, however this increment was only significant for the bFGF + KL group. It can be concluded that KL and bFGF factors individually have no beneficial effects on in-situ follicular growth, but their combination positively influences steroidogenesis of granulosa cells without significantly increasing the number of growing follicles.