Gene injections of vascular endothelial growth factor and growth differentiation factor-9 stimulate ovarian follicular development in immature female rats

ObjectiveTo examine the effect of vascular endothelial growth factor (VEGF) and growth differentiation factor-9 (GDF-9) on follicular development of the ovaries in immature female rats.DesignSuperovulation and gene injection.SettingAnimal reproduction laboratory in Tohoku University, Sendai, Japan.Animal(s)Wister-Imamichi female rats.Intervention(s)The ovulated oocytes from rats with injected VEGF and GDF-9 gene fragments were counted, and the ovaries removed from those rats were used in the histologic observation.Main Outcome Measure(s)Follicular dynamics and angiogenesis after VEGF and GDF-9 gene fragments injection.Result(s)A single injection of the VEGF gene led to the production of a large number of oocytes (approximately 110 oocytes) from an individual animal that was injected with the gene at 21 days after birth, and after mating most of the oocytes were fertilized. Direct ovarian injection of GDF-9 stimulated the development of medium-sized antral follicles. The number of ovulated oocytes after injection of the VEGF plus GDF-9 gene fragments was the same as with a single injection of the VEGF gene.Conclusion(s)A single injection of the VEGF or GDF-9 gene stimulated follicular development, and injection of both genes did increase the number of ovulated oocytes from individual animals. An exogenous gene fragments injection promoted the maximum potential of ovarian function in immature female rats.