Abstract
This study explored the expression and localization of fibroblast growth factor (FGF) 10 and its receptors (FGF receptor 1 and FGF receptor 2, FGFR1 and FGFR2) during buffalo follicular development, laying a foundation for the further study of FGF signaling pathways in follicular development and oogenesis. Granulosa cells and ovarian follicles were extracted from buffalo ovaries, and in vitro maturation culture of oocytes was conducted. Immunohistochemistry was performed to detect the expression of FGF10 and its receptors FGFR1 and FGFR2. In addition, immunofluorescence staining was used to detect the expression of FGF10 in buffalo cumulus oocyte complexes (COCs). Moreover, mRNA levels of FGF10, sub-types of FGFR1 and FGFR2 (FGFR1b and FGFR2b) were measured using qRT-PCR. Immunohistochemistry results showed that FGF10 and its receptors FGFR1 and FGFR2 appeared to have positive responses in buffalo primordial follicles, primary follicles, secondary follicles, and mature follicle oocytes and granulosa cells, and mature follicle basal membrane cells. However, no expression of FGF10 mRNA was detected in granulosa cells from follicles of different diameters, but immunofluorescence results showed that FGF10 could be detected in both cumulus cells and oocytes. With an increase in the vitro maturation time of buffalo COCs, FGF10 and receptor sub-types FGFR1b and FGFR2b mRNA expression also gradually increased, and significantly higher than before maturation. In summary, FGF10 and its receptors may be involved in the process of buffalo follicular development and oocyte maturation.