Figure 3. Lactation induced PLR is blocked by osteocyte-specific disruption of TβRII gene.

Bones from 15- week-old virgin and lactating control and TβRII^ocy−/− female mice were harvested and processed for gene expression (A-B) and immunohistochemistry (C-D). qPCR analysis of TβRII and PLR genes Mmp2, Mmp13, Mmp14, Acp5, Ctsk, AtpD2 and AtpG1 (A-B) in virgin and lactating control and TβRII^ocy−/− mouse bones was compared (n=6–9 mice/ group). Immunohistochemistry (IHC) for MMP13, MMP14, and CTSK was conducted on femoral cortical bones of virgin and lactating control and TβRII^ocy−/− mice. Arrows in the representative images indicate positively stained area (D) that were quantified and normalized to total bone area (C) (n =3–4 mice/group and 4 ROI/mouse, scale bar is 50μm). Representative images of immunofluorescence of TβRII (top) and MMP13 (bottom) protein and (E) quantification of cells positive for TβRII and DAPI, or MMP13 and DAPIIn murine cortical bone (F and G) (scale bar is 40μm) is shown. Error bars indicate mean ± SEM, *p<0.05 compared to control virgins, #p<0.05 compared to control lactation group, and $p<0.05 compared to TβRII^ocy−/− virgin, as calculated from one-way ANOVA with Tukey post-hoc test.