Direct injection of vascular endothelial growth factor into the ovary of mice promotes follicular development.

OBJECTIVE: To investigate the effects of an ovarian injection of vascular endothelial growth factor (VEGF) on antral follicle development, neoangiogenesis, and apoptosis.
DESIGN: Controlled laboratory study.
SETTING: University-affiliated fertility center. ANIMAL(S): Balb/c female mice (n = 32) were studied. INTERVENTION(S): Mice were divided into four groups: control group (C) n = 6, no treatment; hyperstimulated group (HS), n = 8, ovaries were stimulated with 7.5 IU pregnant mare serum gonadotropin (PMSG) and 10 IU of hCG; VEGF group (V), n = 8, injected with 0.1 mL of VEGF (0.2 microg) in each ovary; V+HS, n = 8 injected with VEGF and 2 weeks later hyperstimulated. MAIN OUTCOME MEASURE(S): Number of antral and luteinized follicles, number of vessels, and percentage of Bcl-2-positive cells. RESULT(S): The number of antral follicles with VEGF was higher than in the C and HS groups (16.0 +/- 2.5 vs. 6.0 +/- 0.9 and 11.3 +/- 0.6, respectively, p<0.005). All treatments significantly increased the number of vessels (C: 5.0 +/- 0.5 vs. V: 20.0 +/- 4.8, p<0.005 and V+HS: 22.2 +/- 1.2, p<0.01), as well as increased Bcl-2-positive cells compared to controls (C: 0; V: 11.8 +/- 3.5, p<0.005; V+HS: 12.5 +/- 3.7, p<0.005). CONCLUSION(S): Our findings demonstrated that a direct injection of VEGF into the mouse ovary results in the development of an enhanced vascular network promoting follicular development and diminishing apoptosis.