Evans blue Western blotting 4 animal experiment 4 animal model 4 article 4 blood vessel permeability 4 body weight 4 controlled study 4 cyclooxygenase 2 4 enzyme linked immunosorbent assay 4 estradiol 4 female 4 immunohistochemistry 4 metformin 4 nitric oxide synthase 4 nonhuman 4 ovary follicle 4 ovary hyperstimulation 4 pathophysiology 4 priority journal 4 progesterone 4 protein expression 4 rat 4 vasculotropin 4