Fig. 6.

Impaired osteoclastogenesis in induced SHP-2-deficient mice. (A) Femur sections of tamoxifen-injected moribund ptpn11^fl/fl ert2-cre mice and ptpn11^fl/fl littermate controls were stained for TRAP to visualize osteoclasts (red color). Images are from 11-week-old mice injected with tamoxifen 5 weeks previously. The location of osteoclasts beneath growth plates (g) and within the secondary spongiosa are indicated with blue arrowheads. Note the paucity of osteoclasts in ptpn11^fl/fl ert2-cre mice. Scale bars: top panels, 500 μm; bottom panels, 200 μm. (B) Bone marrow cells from ptpn11^fl/fl ert2-cre mice and ptpn11^fl/fl littermate control mice, both treated with tamoxifen 3 weeks previously (at 7 weeks of age), were cultured with M-CSF and RANKL for 7 days on glass coverslips. Osteoclasts were identified by TRAP staining. Note the abundance of multinucleated osteoclasts in control cultures and absence from ptpn11^fl/fl ert2-cre cultures. Scale bars: 100 μm. (C) Shown are the mean numbers of osteoclasts + 1 s.e.m. per field identified in bone sections (in situ) and in vitro osteoclast differentiation experiments described in A and B. For in situ analysis, the field size was as shown in the top panels of A and encompassed the growth plate and secondary spongiosa regions. Data are derived from randomly selected fields of femur heads from moribund ptpn11^fl/fl ert2-cre mice and ptpn11^fl/fl littermate controls injected with tamoxifen at 6 weeks of age (n=3 in each genotype). Mice were 10–11 weeks of age at the time of analysis. Size of fields in in vitro experiments are as indicated in B and were selected randomly on coverslips. Bone marrow was derived from ptpn11^fl/fl ert2-cre mice and ptpn11^fl/fl littermate mice that were injected with tamoxifen at 6–8 weeks of age (n=6 in each genotype). Osteoclast differentiation experiments were initiated 1–3 weeks thereafter. Statistical significance was determined by paired Student’s t-test. **P<0.005.