Amount of mRNA and localization of vascular endothelial growth factor and its receptors in the ovarian follicle during estrous cycle of water buffalo (Bubalus bubalis)

Abstract The objective of the present study was to characterize the temporal patterns of gene expression for vascular endothelial growth factors (VEGF) and VEGF receptors during ovarian follicular growth, development and maturation in buffalo ( Bubalus bubalis ). Follicles were classified into four groups according to size and the concentration of estradiol-17β (E 2 ) in follicular fluid (FF): Group I (small), 4–6mm diameter, E 2 >0.5ng/ml of FF; Group II (medium), 7–9mm, E 2 =0.5–5ng/ml; Group III (large), 10–13mm, E 2 =5–40ng/ml; Group IV(pre-ovulatory), >13mm, E 2 >180ng/ml). The mRNAs for FSH receptor (FSHR), LH receptor (LHR) and aromatase (CYP19A1) in theca interna and granulosa layers were also determined, further defining the maturational state of each group. The relative expression of VEGF isoforms (120, 164, and 188 amino acid forms), as determined by quantitative real-time PCR (qRT-PCR), increased during follicular development in both the granulosa ( P P