Osx and Satb2 regulate osteoblast differentiation, bone formation and repair / 中国组织工程研究

ABSTRACT

BACKGROUND:Osteoblasts occupy an important role in osteogenesis, which mainly come from bone marrow mesenchymal cels, and some transcription factors or local factors may promote the osteogenic differentiation of bone marrow stromal cels. OBJECTIVE: To study the role of Osx and Satb2 in C2C12cels in the repair process of osteoporosis. METHODS: Twenty wild-type Sprague-Dawley rats were assigned into normal control group (n=10), sham group (n=5) and osteoporosis group (model group,n=5). Another 10 Osx-KO rats were enroled in the study. Osteoporosis models were established by removal of both ovaries in the model group and Osx-KO group. In the sham group, bilateral ovaries were exposed but not removed. Changes in body mass and femoral bone density were detected in the four groups post operation. C2C12 cels were culturedin vitro, and siRNA-Satb2 and siRNA-Osx were designed. Expressions of Osx and Satb2 and their effects on osteoporosis were observed using cel experiments, gene silencing and western blot assay. RESULTS AND CONCLUSION:After 12 weeks, the body mass in the model and Osx-KO groups was significantly increased compared with the normal control and sham groups (P< 0.01); the bone density in the model and Osx-KO group was significantly decreased compared with the normal control and sham groups (P < 0.01). Satb2 and Osx were expressed in al the wild-type rats, but their expressions were decreased significantly in the Osx-KO rats (P < 0.001). Additionally, there was no difference in the Runx2 mRNA expression between the two kinds of rats. After silencing, the mRNA expressions of Satb2, Osx, Runx2 and ALP were al inhibited. These findings indicate that in the pathogenesis of osteoporosis, Osx and Satb2 may be protective molecules that have a regulatory role in the osteogenic differentiation, bone formation and repair.