Follicle stimulating hormone and fibroblast growth factor-2 interact and promote goat primordial follicle development in vitro

Abstract

The aims of the present study were to investigate the effects of the interaction between follicle stimulating hormone (FSH) and fibroblast growth factor-2 (FGF-2) on survival, follicular growth initiation and further growth of caprine preantral follicles. Pieces of caprine ovarian cortex were cultured for 1 or 7 days in minimum essential medium (MEM) supplemented with FSH, FGF-2 or FSH + FGF-2. Small fragments from non-cultured ovarian tissue and from those cultured for 1 or 7 days were processed for classical histology and transmission electron microscopy (TEM) to verify follicular morphology and growth. The results showed that, after 7 days culture, the highest percentages of normal follicles were observed in medium supplemented with FSH. After 7 days culture, the interaction between FSH and FGF-2 was most effective to promote the initiation of primordial follicles growth and oocyte growth. TEM showed ultrastructural integrity of follicles after 1 day of culture in MEM and after 7 days in all treatments, except in those follicles cultured for 7 days in MEM. In conclusion, this study demonstrated that the interaction between FSH and FGF-2 stimulates the initiation of primordial follicles growth and the subsequent growth of developing follicles. Furthermore, these data showed that FSH is important to maintain follicular integrity after 7 days culture.

In vitro development of primordial follicles after long-term culture of goat ovarian tissue

“…In contrast, the other treatments (FSH-7d and FSH + FGF-2) were effective in maintaining follicle ultrastructural integrity up to day 7. Our light histological results confirm earlier studies in which FSH maintained preantral follicle viability after short (Matos et al, 2007a andMatos et al, 2007c) or long-term culture (Cortvrindt et al, 1997, Wright et al, 1999and Gutierrez et al, 2000. It is suggested that the absence of FSH in the medium could compromise the diffusion of several essential chemical and physical factors through the basement membrane (Hsueh et al, 1994).…”

“…Thus, some follicles could die after activation due to an improper environment for continuing their normal development (Rüsse, 1983). Recently, we have demonstrated that FSH could improve caprine follicular activation (Matos et al, 2007a andMatos et al, 2007c). In addition, Joyce et al (1999) reported that FSH stimulates Kit ligand mRNA expression in the granulosa cells of preantral follicles, which is essential for the initiation of primordial follicle growth (Parrot and Skinner, 1999).…”

“…We have demonstrated that an interaction between FSH and FGF-2 promoted caprine follicular activation and oocyte growth (Matos et al, 2007c) in a 7 days culture system. However, there are apparently no reports showing the effects of FSH alone or in association with FGF-2 on follicular activation and growth after the long-term culture of caprine ovarian tissue.…”

“…Additionally, after 7 days of culture, higher percentages of normal follicles were observed only in medium supplemented with FSH (66.7%) when compared with MEM+ (56.3% -control medium). Finally, with the increase of the culture period from 1 to 7 days, a decrease in the percentage of normal follicles was observed in all treatments, but not in medium supplemented only with FSH (Matos et al, 2007c). Therefore, we decided to exclude the treatment with FGF-2 only from the present study.…”

“…The follicular and oocyte diameters were measured in 20 follicles for each treatment. Care was taken to count each follicle only once, as has also been done in our earlier studies (Matos et al, 2007a, Matos et al, 2007band Matos et al, 2007c; thus, only follicles with a visible oocyte nucleus were recorded.…”