FIG 8.
Stalled osteogenic differentiation in Rptorob−/− OBs. (A) Hematoxylin and eosin staining (H&E) and IHC staining of osterix and osteocalcin in the primary spongiosa of tibial sections from 4-week-old Osx:cre (cre) and Rptorob−/− (hom) mice. Scale bar, 50 μm. (B) Quantitative PCR was performed on RNA extracted from eYFP+ cells isolated from eYFP-Osx:cre and eYFP-Rptorob−/− mice. The expression levels of the indicated genes relative to β-actin are shown. (C) Calvarial cells isolated from 4-week-old Osx:cre and Rptorob−/− mice were cultured under osteogenic conditions, and the levels of acid-soluble mineral were quantified and expressed relative to the total DNA. Mineralized matrix was stained using alizarin red. HZ, hypertrophic zone; PS, primary spongiosa. Measurements are presented as means ± the SD from three independent experiments.*, P < 0.05; **, P < 0.01; ***, P < 0.001.