CCR3 antagonist impairs estradiol-induced eosinophil migration to the uterus in ovariectomized mice

Eosinophils are abundant in the reproductive tract, contributing to the remodeling and successful implantation of the embryo. However, the mechanisms by which eosinophils migrate into the uterus and their relationship to edema are still not entirely clear, since there are a variety of chemotactic factors that can cause migration of these cells. Therefore, to evaluate the role of CCR3 in eosinophil migration, ovariectomized C57BL/6 mice were treated with CCR3 antagonist SB 328437 and 17β-estradiol. The hypothesis that the CCR3 receptor plays an important role in eosinophil migration to the mouse uterus was confirmed, because we observed reduction in eosinophil peroxidase activity in these antagonist-treated uteruses. The antagonist also influenced uterine hypertrophy, inhibiting edema formation. Finally, histological analysis of the orcein-stained uteruses showed that the antagonist reduced eosinophil migration together with edema. These data showed that the CCR3 receptor is an important target for studies that seek to clarify the functions of these cells in uterine physiology.