RESUMO
<p><b>OBJECTIVE</b>To study the effects of 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] on the expression of osteoprotegerin (OPG) and receptor activator of NF-kappaB ligand (RANKL) mRNA in mouse osteoblasts.</p><p><b>METHODS</b>Calvariae derived from CD-1 neonatal mouse (after born 24 h). Bone samples were processed by the collagenase/trypsin digestion method. Mouse osteoblasts were cultured in vitro. After 48 hours of addition of 1,25(OH)2D3 (0, 10(-8), 10(-9), 10(-11) mol/L) to the culture medium of mouse osteoblasts, the content of the OPG protein in culture medium was estimated with enzyme linked immunosorbent assay. Total RNA was prepared from mouse osteoblasts. mRNA expression of OPG and RANKL were detected by reverse transcription-polymerase chain reaction.</p><p><b>RESULTS</b>The mRNA expression of OPG in osteoblasts added with 1,25(OH)2D3 significantly decreased compared with the controls, which was markedly dose-dependent. OPG protein production in the medium decreased after treatment with 1,25(OH)2D3. In contrast, RANKL mRNA expression levels in osteoblasts significantly increased after 48 h of culture with 1,25(OH)2D3.</p><p><b>CONCLUSION</b>1,25 (OH)2D3 can stimulate RANKL mRNA expression, but decrease OPG mRNA levels in vitro in mouse osteoblasts.</p>
Assuntos
Animais , Camundongos , Animais Recém-Nascidos , Calcitriol , Farmacologia , Proteínas de Transporte , Genética , Glicoproteínas , Genética , Fisiologia , Ligantes , Glicoproteínas de Membrana , Genética , NF-kappa B , Genética , Osteoclastos , Metabolismo , Fisiologia , Osteoprotegerina , Ligante RANK , RNA Mensageiro , Genética , Receptor Ativador de Fator Nuclear kappa-B , Receptores Citoplasmáticos e Nucleares , Genética , Fisiologia , Receptores do Fator de Necrose Tumoral , Genética , Fator de Necrose Tumoral alfa , GenéticaRESUMO
Objective To investigate the effects of 1,25(OH)_2D_3 on cell proliferation and cell cycle progression in mouse osteoblasts.Methods Sterile bones of skull of mouse were taken from 30 newborn mouse,and the osteoblast were separated by enzyme digestion methods.After 1,25(OH)_2D_3 in different concentrations were added into culture medium,the effects of 1,25(OH)_2D_3 on cell proliferation of mouse osteoblasts and on cell cycle progression were examined by mono-nuclear celldirect cytotoxicity assay(MTT)reduction assay and flow cytometry respectively.Results After 24,48,72 h of 1,25(OH)_2D_3 incubation,the cell number of osteoblast had significant difference among groups of 1,25(OH)_2D_3 of 10~(-8),10~(-9),10~(-11)mol/L.Significant differences were found in the cell cycle progression in response to 1,25(OH)_2D_3 treatment from the Gl(84.30?1.90)to the G2-M (7.70?0.667)and S(8.00?1.42)phases when compared with those in the control group. Conclusions Cell proliferation of mouse osteoblasts can be inhibited by 1,25(OH)_2D_3 in a concentration-dependent manner.