Fig. 5: Slitrk5 deficient mice display increased bone formation.

a RT-PCR analysis of hedgehog signaling related gene expression in the tibias of 8-week-old WT and Slitrk5^−/−. n = 11 or 12 per group. Two-tailed unpaired t test. b RNA in situ hybridization analysis using Gli1 probe in the tibias of WT and Slitrk5^−/− mice at 4 day old. Data are representative of two independent experiments, scale bar = 200 µm. c–f Calcein double labeling (c, e) and quantification of histomorphometric parameters (d, f) of the L3 vertebrae trabecular bone (c, d) and cortical bone (e, f) in 7-week-old WT and Slitrk5^−/− female mice. Mineral apposition rate (MAR, µm/day), bone formation rate/bone surface (BFR/BS) (mm³/mm²/year). N = 7–9 per group. Data are presented as mean ± s.d, two-tailed unpaired t test, data in (c, e) are representative of 7 (WT) or 9 (Slitrk5^−/−) independent samples. Scale bar = 250 µm (c) and 25 µm (e). g, h Toluidine blue staining (g) and quantification of Ob.S/BS (h) of the L3 vertebrae in WT and Slitrk5^−/− female mice at 7 week old. Osteoblast surface/bone surface (Ob.S/BS), n = 6 per group. Data are presented as mean ± s.d, two-tailed unpaired t test, data in (g) are representative of six independent samples, scale bar = 100 µm. i Representative μCT 3D images of mouse femurs at 21 days after open femoral midshaft fracture, scale bar = 1 mm. j μCT measurement of BV/TV in callus area in WT and Slitrk5^−/− mice at 21 days post-surgery. N = 6 or 7 per group. Data are presented as mean ± s.d, two-tailed unpaired t test. k Representative H&E staining images of fracture callus from in WT and Slitrk5^−/− mice at 21 days after an open femoral midshaft fracture. Data are representative of three independent experiments, scale bar = 100 µm. l RNA in situ hybridization analysis using Gli1 and Col1a1 probes in the callus area of WT and Slitrk5^−/− mice at 12 days post-surgery. Data are representative of two independent experiments, scale bar = 100 µm. m RT-PCR analysis of Gli1, Col1a1, and Slitrk5 expression in the fracture callus from WT and Slitrk5^−/− mice at 12 days after open femoral midshaft fracture, n = 13 or 14 per group. Two-tailed unpaired t test.