Expression and localization of fibroblast growth factor (FGF) family in corpus luteum during different stages of estrous cycle and synergistic role of FGF2 and vascular endothelial growth factor (VEGF) on steroidogenesis, angiogenesis and survivability of

The aim of this study was to document the expression and localization of fibroblast growth factor (FGF) family members comprising of fibroblast growth factor (FGF1, FGF2, FGF7, FGF10), and their receptors (FGFR1, FGFR2, FGFR3, FGFR4, FGFR2IIIB, FGFR2IIIC) in buffalo corpus luteum (CL) obtained at different stages of the estrous cycle. In addition, the synergistic role of FGF2 and/or vascular endothelial growth factor (VEGF) on P4 secretion and mRNA expression of steroidogenic acute regulatory protein (StAR), cytochrome P450 (CYP11A1), 3-beta-hydroxysteroid dehydrogenase (3βHSD), proliferating cell nuclear antigen (PCNA), BCL-2 associated X protein (BAX) and von willebrand factor (vWF) were studied in luteal cell culture obtained from mid-luteal phase (MLP) of estrous cycle in buffalo. Real-time PCR (qPCR), western blot, and immunohistochemistry were used to investigate mRNA and protein expressions, and the localization of examined factors whereas P4 secretion was assessed by RIA. The mRNA and protein expression of FGF1 and FGFR1 were maximum (P < 0.05) during MLP whereas FGF2 was maximum (P < 0.05) during early luteal phase (ELP). FGF7, FGF10, FGFR2, FGFR3, FGFR4, FGFR2IIIb, and FGFR2IIIc mRNA and protein expression did not change among luteal phases. FGF family members were localized in cytoplasm of luteal cells as well as in endothelial cells. P4 secretion in luteal cells treated with FGF2 or VEGF alone showed the maximum values (P < 0.05) with the highest dose at 72 h. P4 secretion was found to be greater (P < 0.05) in luteal cells treated with FGF2 + VEGF compared to FGF2 or at 72 h of incubation. The mRNA expression of all factors were maximum (P < 0.05) whereas BAX was minimum (P < 0.05) at highest dose cultured for 72 h of luteal cells subjected with either protein alone or in combination. Summarizing, the present findings explore the synergistic role of FGF2 and VEGF on steroidogenesis, angiogenesis, cell viability through an autocrine and paracrine actions in buffalo CL.