Overexpression of Bcl2 in Osteoblasts Inhibits Osteoblast Differentiation and Induces Osteocyte Apoptosis
Figure 6
Expression of apoptosis-related molecules and TUNEL staining of cortical bone in p53−/−tg(H).
(A) Real-time RT-PCR analysis of apoptosis-related genes and Vegf. RNA was extracted from osteocyte-enriched samples of tibiae and femurs of male wild-type mice (blue) and tg(H) (yellow). The values of wild-type mice were defined as 1, and relative levels are shown. Data are presented as the mean ± S.D. of 4–10 mice at 5–6 weeks of age. *vs. wild-type mice. *P<0.05, **P<0.01. (B, C) Western blot analysis of apoptosis-related molecules using cell extract from osteoblast-enriched fraction (B) and osteocyte-enriched fraction (C) in male wild-type mice (wt) and tg(H) at 5–6 weeks of age. β-actin was used as an internal control. The anti-Bcl2 antibody used here reacts with both mouse and human Bcl2. Similar results were obtained in three independent experiments and representative data are shown. (D–H) Failure to rescue osteocyte apoptosis by the deletion of p53. H-E (D, E) and TUNEL (F, G) staining of sections of cortical bone at the diaphyses of femurs of male tg(H) (D, F) and p53−/−tg(H) (E, G) and the frequencies of TUNEL-positive lacunae (H) at 10 weeks of age. Scale bars: 0.1 mm. Data are presented as the mean ± S.D. of 3 mice.