Vascular Endothelial Growth Factor (Vegf) Localization in the Mammary Gland at Various Stages of its Physiological Cycle; A Histological and Immunohistochemical Study

Introduction: Vascular Endothelial Growth Factor (VEGF) is a potent angiogenic and vascular permeability enhancing factor under both physiological and pathological conditions including tumor angiogenesis. Aim of the Work: To study the localization and intensity of VEGF in the mammary gland at various stages of its physiological cycle. Materials and Methods: Mammary glands from sixty female albino rats were divided into six groups (10 rats each): Group I nulliparous, group II early pregnancy, group III late pregnancy, group IV lactating, group V early involution and group VI late involution. Human specimens from five females of variable age (childbearing and post-menopausal) were examined. Animal specimens were subjected to histological study while all specimens were subjected to immunohistochemical detection of VEGF. Morphometric analysis was performed for area % and optical density of positive VEGF reaction. Results: VEGF was detected in epithelial lining of ducts and acini, endothelium of blood vessels as well as some stroma cells and macrophages. It was detected in resting nulliparous rat mammary gland with an increase during early pregnancy that became remarkable in late pregnancy and reached its maximum during lactation. Furthermore, VEGF was also detected in milk within lactating mammary acini. During involution, VEGF decreased progressively and reached a minimum in late involution. Human specimens showed stronger VEGF reaction during childbearing period than in post-menopause. Conclusion: The localization of VEGF in the endothelial cells of blood vessels, epithelium of mammary gland ducts and acini as well as some stroma cells and macrophages denoted that it is secreted by those cells. The increased VEGF in pregnancy and lactation indicates that it plays an important role in the development and function of the mammary gland.