Expression of Vascular Endothelial Growth Factor (VEGF) and its receptors in the golden hamster uterus during implantation

Abstract

Expression of VEGF and its receptors Flt-1 and Flk-1 during embryonic implantation (days 3-7) was studied in the uterus by immunohistochemistry. The lectin BS-1 (Bandeiraea simplicifolia) was used to label newly-formed endothelial cells. VEGF was expressed by all embryonic cells between days 4-7. VEGF and Flt-1 expression was observed in decidual cells on days 5-7. Flk-1 immunoreactivity was localized in newly-formed endothelial cells sprouting at the antimesometrial pole. BS-1 binding was found in decidual cells at the antimesometrial pole. Our data indicate that VEGF and its receptors may play a role in facilitating blood supply at the implantation site. The fact that VEGF is found in the embryo a day earlier suggests that the implanting conceptus may signal implantation by initiating angiogenic response in the endometrium.