Role of VEGF in pig preantal follicles

Follicle selection is intimately dependent on follicular angiogenesis, and thatVEGF plays a relevant role in this context. This study examines the process of vascularremodelling during pig preantral follicles (PA) development. Ovarian tissues, collected at theslaughterhouse, were analyzed to quantify vascular area (VA) using an endothelial marker(vWF), and the proliferation index (PI) of the somatic cell with the Ki-67. Simultaneously, theVEGF protein and mRNA expression pattern has been considered. This study shows during thefirst stage of PA follicular development a positive correlation among PI, VA and VEGFexpression. By contrast during the late stage of PA growth the VA remains constant as well asthe PI with a high content of VEGF mRNA and protein. This data show that VEGF upregulationmay represent a prerequisite for PA to enter in the growing follicular pool to beselected.[...]