Because we had not seen epithelial and stromal cell staining in our previous study of the normal estrous cycle, we reexamined this question with the better antibody preparation used in this study. With the more avid antibody preparation we now detected CRBP staining in the luminal epithelial cells at estrus (coincident with the expression of CRABP[II]) and detected stromal cell staining during dies-trus. Only faint or no staining was noted for CRBP at these sites during proestrus and metestrus (Fig. 2, G and H, and data not shown). The intensity of CRBP staining in the normally cycling animal was less than that seen in the luminal epithelium at Day 1 of pregnancy, which perhaps contributed to the failure to detect staining with the weaker antibody preparation (data not shown).

Cell-Specific Localization of CRABP

CRABP expression was primarily in the layers of smooth muscle. In some areas of the uterus, the intensity of the staining was stronger on the mesometrial side than on the antimesometrial side (Fig. 3 and data not shown). This staining pattern was noted for all days examined. The intensity of staining decreased after Day 1 (Fig. 3, A-C). On Day 1, in addition to the muscle staining, some of the stromal cells on the mesometrial side were positive for CRABP, including the stromal cells that had been positive for CRBP (Fig. ЗА and data not shown). No specific staining was detected in the stromal cells on the antimesometrial side (Fig. ЗА). The stromal staining for CRABP was very region dependent. Stronger staining for CRABP was seen for stromal cells on the mesometrial side near the oviduct than was seen in the middle uterus or near the cervical end (data not shown). No positive staining was seen in the decidual cells on Day 6 and Day 7 (Fig. 3, D and E); but on Day 7, some stromal cells in the implantation chamber on the mesometrial side showed weak immunostaining for CRABP (data not shown). buy levaquin online
Fig3Spatial and temporal patternsFIG. 3. Immunohistochemical localization of CRABP in the rat uterus during the periimplantation period. The affinity-purified IgG fraction that recognizes CRABP (see Fig. 1) was used for analysis of the expression of CRABP. All sections were lightly counterstained as above. 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 on the mesometrial side of stromal cells underlying the epithelium (open arrowheads) and the lack of staining of the epithelium (filled arrowhead). The smooth muscle cell layers also stained for CRABP (empty arrows). B) Section of the uterus at Day 3. Note darker staining of the smooth muscle cells on the mesometrial side (empty arrow). C) Uterus at Day 4. Note darker staining of the smooth muscle on the mesometrial side (empty arrow). D) Uterus at Day 6. Note darker staining of the smooth muscle on the mesometrial side (empty arrow) and no staining in decidual cells (filled arrow). E) Section of uterus at Day 7 showing lack of staining of primary (filled arrow) and secondary (double star) decidual cells on the antimesometrial side. F) Longitudinal section of the uterus at estrus, showing that stromal cells underlying the epithelium are positive (empty arrowhead). All bars = 100 jj.m, except inset of A, where bar = 10 |xm.