Bone marrow origin of decidual cell precursors in the pseudopregnant mouse uterus

Abstract

Decidual cells are considered to be the endproduct of a hormonally induced transformation of endometrial stromal cells of the uterus. However, the source of these precursors remains unknown. This study evaluated the possibility of their bone marrow origin by an examination of the H-2 phenotype of decidual cells in pseudo-pregnant bone marrow chimeras. These chimeras were produced by repopulating lethally irradiated CBA/J female (H-2(k)) mice with bone marrow from (CBA/J x C57BL/6J)F1 female (H-2(kb)) mice. Pseudopregnancy was produced with a hormonal regimen followed by an oil-induced decidual stimulus. Chimerism was evaluated with an immunolabeling technique with monospecific anti-H-2 serum followed by radioiodinated protein A. The extent of chimerism as indicated by the degree of K(b) labeling on decidual cells as well as macrophages contained with the decidual nodules was quantitatively compared with that seen on splenic lymphocytes. Fair to good chimerism, as reflected by labeling for the donor-specific marker (K(b)), was seen on splenic lymphocytes and macrophages with the decidual nodules in 6 out of 11 animals. A similar level of chimerism was detected on decidual cells in all but one of these six, in which case this was low. One animal showed low chimerism in the spleen but good chimerism on the decidual cells. The remaining four mice were nonchimeric for all three cells types. These results indicate that decidual cells and macrophages appearing within the decidual nodules of pseudopregnant mice are ultimate descendants of bone marrow cells.