Stimulatory effect of vascular endothelial growth factor on progesterone production and survivability of cultured bubaline luteal cells

The objectives of the present study were to investigate the effects of vascular endothelial growth factor (VEGF) on progesterone (P4) synthesis in cultured luteal cells from different stages of the estrous cycle and on expression of steroidogenic acute regulatory protein (STARD1), cytochrome P450 cholesterol side chain cleavage (CYP11A1) and 3β-hydroxysteroid dehydrogenase (HSD3B), antiapoptotic gene PCNA, and proapoptotic gene BAX in luteal cells obtained from mid-luteal phase (MLP) of estrous cycle in buffalo. Corpus luteum samples from the early luteal phase (ELP; day 1st-4th; n = 4), MLP (day 5th-10th; n = 4), and the late luteal phase (LLP; day 11th-16th; n = 4) of oestrous cycle were obtained from a slaughterhouse. Luteal cell cultures were treated with VEGF (0, 1, 10 and 100 ng/ml) for 24, 48 and 72 h. Progesterone was assessed by RIA, while mRNA expression was determined by quantitative real-time PCR (qRT-PCR). Results indicated a dose- and time-dependent stimulatory effect of VEGF on P4 synthesis and expression of steroidogenic enzymes. Moreover, VEGF treatment led to an increase in PCNA expression and decrease in BAX expression. In summary, these findings suggest that VEGF acts locally in the bubaline CL to modulate steroid hormone synthesis and cell survivability, which indicates that this factor has an important role as a regulator of CL development and function in buffalo.