RESUMEN
Objective:To investigate the effect of steroid hormones on distribution of uterine natural killer(uNK)cells in the mouse uterus.Methods:A unique uNK cell marker, Dolichos biflorus agglutinin(DBA)lectin was used to localize uNK cells in the ovariectomized and ovarian steroid hormone-treated mouse uterus by immunohistochemical staining.Results: After estrogen(E_2)was administered in the ovariectomized mice, uNK cells were distributed in the stroma of uterine mesometrial pole,as round, immature and small lymphocyte-like cells.With the progesterone(P_4)administered, the immunostaining results showed that DAB-lectin staining were mainly distributed in the vascular endothelial cells.With the combination of E_2 and P_4, DAB-lectin staining was distributed in the matrix of the uterus,seen as a number of small round uNK cells or some as vascular endothelial cells.The effects could be completely abolished by specific antagonists of their nuclear receptors(estrogen and progesterone receptor).Conclusion: The distribution of uNK cells in mouse uteri is collaboratively regulated by estrogen and progesterone.The endometrial uNK cells may be involved in the mechanism of the fetal protective immune reaction during pregnancy.