Ovarian Steroid Hormone-Regulated Uterine Remodeling Occurs Independently of Macrophages in Mice

ABSTRACT Macrophages are abundant in the uterine stroma and are intimately juxtaposed with other cell lineages comprising the uterine epithelial and stromal compartments. We postulated that macrophages may participate in mediating or amplifying the effects of ovarian steroid hormones to facilitate the uterine remodeling that is a characteristic feature of every estrus cycle and is essential for pregnancy. Using the Cd11b-Dtr transgenic mouse model with an ovariectomy and hormone replacement strategy, we depleted macrophages to determine their role in hormone-driven proliferation of uterine epithelial and stromal cells and uterine vascular development. Following diphtheria toxin (DT) administration, approximately 85% of EMR1-positive (EMR1+) macrophages, as well as 70% of CD11C+ dendritic cells, were depleted from Cd11b-Dtr mice. There was no change in bromodeoxyuridine incorporation into epithelial cells induced to proliferate by administration of 17beta-estradiol (E2) to ovariectomized mice or into strom...