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 mug) 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. (C) 2004 by American Society for Reproductive Medicine.