Figure 1.

BMP4 expression and regulation in the adult rat vagina. A, Low-magnification image shows gross histology of the vagina in cross-section. α-Smooth muscle actin-IR reveals the submucosal smooth muscle layer (red), which lies beneath the epithelium demarcated by the dense aggregation of DAPI-stained nuclei (blue). B, BMP4-IR (red) is expressed almost exclusively within smooth muscle (SM) lying beneath the epithelium (E), and this corresponds to the location of most peripherin-positive axons (green). C, Preabsorption of the BMP4 antibody with an excess of mouse recombinant BMP4 eliminated staining of vaginal tissues. Scale bars, 50 μm. D, Submucosal vaginal tissue explants cultured for 24 h with 20 nm estrogen (E2) show reduced BMP4 gene expression by RT-PCR relative to GAPDH compared with untreated controls (C). E, In vivo treatment of OVX rats for 7 d with estrogen also reduced BMP4 protein levels relative to β-actin as assessed by immunoblot.