Growth and differentiation factor-9 stimulates activation of goat primordial follicles in vitro and their progression to secondary follicles

Abstract

The aim of the present study was to investigate the effects of growth and differentiation factor-9 (GDF-9) on the survival and activation of preantral follicles, as well as their subsequent progression to secondary follicles, using goat ovarian cortical culture in vitro. Pieces of ovarian cortex were cultured for 1 and 7 days in minimum essential medium (MEM) with or without different concentrations of GDF-9 (1-200 ng mL(-1)). On Day 0 and after 1 and 7 days of culture, cortical pieces were fixed for histological and transmission electron microscopy evaluation. Preantral follicles were classified according to their development stage (primordial, intermediate, primary and secondary) and on the basis of morphological features (normal or degenerated). In addition, follicular and oocyte diameters were determined before and after culture. The results showed that, compared with non-cultured cortical tissue (Day 0), the culture of ovarian tissue significantly reduced (P < 0.05) the percentage of normal follicles in all media tested, except for tissue cultured in the presence of 200 ng mL(-1) GDF-9. Furthermore, in all media tested, the percentage of primordial follicles was significantly reduced (P < 0.05), with a concomitant increase in the percentage of developing follicles. The highest percentage of secondary follicles was observed after 7 days of culture in MEM plus 200 ng mL(-1) GDF-9. At all concentrations of GDF-9 tested, follicular diameter increased significantly after 7 days of culture compared with non-cultured cortical tissue. In conclusion, the results of the present study indicate that 200 ng mL(-1) GDF-9 maintains the survival of preantral follicles and promotes activation of primordial follicles. Furthermore, GDF-9 stimulates the transition from primary to secondary follicles, maintaining ultrastructural integrity of the follicles.

Interaction between growth differentiation factor 9, insulin-like growth factor I and growth hormone on the in vitro development and survival of goat preantral follicles

“…However, in our culture conditions, an elevated activation was observed after the addition of IGF/GH to the culture medium. Follicular activation has been obtained in previous studies in goats (11), cows (34,35) and baboons (36), in which the number of primordial follicles was dramatically reduced, with a concomitant increase in the number of developing follicles after in vitro culture of ovarian tissue. Studies have demonstrated that GH stimulates the production of IGF-I and its messenger RNA (mRNA) in porcine granulosa cells and rat ovary (37).…”

“…Deletion of the GDF-9 gene in mice blocked folliculogenesis at the primary stage, demonstrating the importance of this growth factor in early follicular development (29). Subsequent studies have shown that treatment with GDF-9 stimulates granulosa cell proliferation in rats (9), preantral follicle growth in humans (30) and goats (11) and cumulus cell expansion in humans (31) and results in a higher proportion of viable human follicles in organ culture, suggesting a possible role for GDF-9 in follicular survival (10). Moreover, the presence of GDF-9 in primary and later-stage goat follicles (32) suggests that GDF-9-mediated signaling events may be important for the development of preantral follicles in this species.…”

“…Furthermore, recent studies have shown that GDF-9 stimulates the in vitro growth of preantral follicles and thecal cell differentiation in the rat (5,9) as well as primary and early secondary follicle formation in human ovarian slices in vitro (10). Recently, we have demonstrated that GDF-9 promotes in vitro follicular survival, growth and progression to the secondary follicle stage in goats, maintaining follicular ultrastructure (11). There is a growing body of evidence showing that IGF-I plays a key role in the development of preantral follicles and in the process of follicular atresia.…”

In vitro culture of sheep lamb ovarian cortical tissue in a sequential culture medium

“…Similarly, the various influences on the growth factors in ovarian follicle development have not been very uniform among different species. Studies have demonstrated the involvement of follicle-stimulating hormone (FSH) [1][2][3], growth and differentiation factor 9 (GDF-9) [4][5][6][7], basic fibroblast growth factor (bFGF) [8][9][10], insulin [11], and epidermal growth factor (EGF) [12][13][14] in early follicular development. Other factors that were incorporated in the present study are based on these references.…”

Growth of Primordial Oocytes in Neonatal and Adult Mammals

“…GDF-9 is expressed in growing oocytes but not in primordial oocytes in rodents [50,51] and humans [52]. However, it stimulates the development of primordial follicles in human [53], goat [54] and hamster ovaries [55]. Bone morphogenetic protein 15 (BMP-15), another member of the TGF-β family, is expressed in growing oocytes but not in primordial oocytes [56][57][58].…”