RESULTS(2)Cell-Specific Localization of CRBP

Incubation of uterine sections with anti-CRBP resulted in staining of both the inner and outer muscle layers throughout the periimplantation period (Fig. 2). The intensity was uniform for both layers of smooth muscle at Day 1. However, after Day 1, the staining intensity of the smooth muscle became region dependent. In some areas, the staining for CRBP was stronger on the mesometrial side than on the antimesometrial side (Fig. 2B). At Day 1, in addition to the staining of smooth muscle cells, strong staining was noted in many of the cells of the luminal epithelium and also some stromal cells, localized to the mesometrial side of the uterus (Fig. 2A).
Scattered and fewer cells of the luminal epithelial and in the stroma were stained on the antimesometrial side (Fig. 2A). There was no apparent staining of the glandular epithelial cells (data not shown). The epithelial staining disappeared after Day 1; then weaker staining of the luminal epithelium was noted on Day 4 and Day 5 (Fig. 2C and data not shown). Human endometrium has also been found to express CRBP in both stroma and epithelial cells. buy ampicillin
After blastocyst attachment, from Day 6 onward, distinct immunoreaction for CRBP was observed in the primary decidual cells around the implantation chamber. On Day 7, the smooth muscle cell layers and the secondary decidual cells at the antimesometrial side, the side of implantation, expressed higher levels of CRBP than the other side (Fig. 2, D-F).
Fig2Spatial and temporal patternsFIG. 2. Immunohistochemical localization of CRBP in the rat uterus during the periimplantation period. The affinity-purified IgG fraction that recognizes CRBP (see Fig. 1) was used for analysis of the expression of CRBP in the uterus. The brown color indicates the presence of immunoreactivity. All sections were lightly counterstained with hematoxylin to reveal cellular detail. A) Longitudinal section of the uterus at Day 1 of pregnancy. The antimesometrial side is to the left. Inset) Higher-power view of the mesometrial side. Note the strong staining of the mesometrial epithelial cells (filled arrowheads), staining of smooth muscle on both sides (open arrows), and lighter staining of some stromal cells on the mesometrial side (open arrowhead). B) Section of the uterus at Day 3. Note lack of staining of the epithelium and darker staining of the smooth muscle cells on the mesometrial side (empty arrows). C) Uterus at Day 4. Note the increased staining of the luminal epithelium (filled arrowhead) compared to Day 3. D) Uterus at Day 6 showing strong staining of decidual cells (filled arrow, antimesometrial side). The embryo is visible in the central lumen. E) Section of the uterus at Day 7 showing staining of primary (filled arrow) and secondary (double star) decidual cells on the antimesometrial side. F) Similar section at Day 7 of the mesometrial side showing decreased staining in the smooth muscle cell layers (empty arrow; compare to the smooth muscle in E) and decidual cells (double star). G) Cross section of uterus at diestrus in the normally cycling rat. Note the staining of stromal cells underlying the epithelium (open arrowhead). A very few epithelial cells also may be stained. H) Longitudinal section of the uterus at estrus showing that most of the epithelial cells are now positive (filled arrowhead). All bars = 100 (Jim, except inset of A, where bar = 10 ^m.