RESUMEN
Previous studies have demonstrated that carbonate apatite (CA) is superior to hydroxyapatite (HA) and ß-tricalciumphosphate (ß-TCP) with regard to osteoclastic resorption, but evidence on osteoclast and osteoblast response remains controversial. In the present study, the expression of bone related mRNA is examined on CA, HA, ß-TCP, and titanium plates. ICR mouse osteoblast cells are cocultured with ICR mouse bone marrow cells. Crude osteoclast-like cell-rich suspensions are then seeded onto plates and cultured for 48 h. Total RNA is extracted and mRNA expression is examined by real-time RT-PCR. Amounts of vacuolar-type ATPase, cathepsin K, and TRAP mRNA are significantly greater on CA than on the other plates. The amount of osteoprotegerin mRNA is significantly greater on CA than on the other plates. RANKL mRNA expression, which is generally regarded as an osteoblast maker, varies with material, but shows no significant differences between CA and the other plates. The formation and activity of osteoclasts is greater with CA than with the other plates. Thus, CA is superior to ß-TCP as a bioresorbable bone substitute for tissue engineering.
Asunto(s)
Apatitas , Materiales Biocompatibles , Osteoblastos/metabolismo , Osteoclastos/metabolismo , Fosfatasa Ácida/genética , Animales , Sustitutos de Huesos , Fosfatos de Calcio , Catepsina K/genética , Técnicas de Cultivo de Célula , Colágeno Tipo I/genética , Durapatita , Expresión Génica , Isoenzimas/genética , Ensayo de Materiales , Ratones , Osteoblastos/citología , Osteoclastos/citología , Osteoprotegerina/genética , Ligando RANK/genética , ARN Mensajero/genética , ARN Mensajero/metabolismo , Fosfatasa Ácida Tartratorresistente , Ingeniería de Tejidos , ATPasas de Translocación de Protón Vacuolares/genéticaRESUMEN
Physiological root resorption is a phenomenon that normally takes place in deciduous teeth; root resorption of permanent teeth occurs only under pathological conditions. The molecular mechanisms underlying these processes are still unclear. Our previous study showed that osteoclasts cultured on deciduous dentine exhibited a higher degree of resorption and higher levels of cathepsin K and MMP-9 mRNA than osteoclasts cultured on permanent dentine. These results could be because of different susceptibilities to acid and the different organic matrices between deciduous and permanent dentine. Thus, the purpose of this study was to investigate the effect of dentine extracts from bovine deciduous and permanent dentine on osteoclast activity. Osteoclasts, obtained from mouse bone marrow cells co-cultured with an osteoblast-rich fraction in the presence of 1,25-(OH)(2)-vitamin D3 and PGE2, were incubated with or without 0.6 M HCl extracts from bovine deciduous or permanent dentine for 48 h. TRAP positive cell number, TRAP activity, the areas of resorption pits, and mRNA levels of TRAP, v-ATPase, calcitonin receptor, cathepsin K, and MMP-9 were examined. The results illustrated that TRAP activity, the resorbed area, and the mRNA levels of osteoclast marker genes seemed to be suppressed by both deciduous and permanent dentine extracts. These findings indicate that some factors that suppress osteoclast activity are contained in both deciduous and permanent dentine extracts. Although there was no significant difference in osteoclast activity between deciduous and permanent dentine extracts, osteoclasts incubated with permanent dentine extracts tend to exhibit less resorption activity than those incubated with deciduous dentine extracts. However, we could not clearly explain the causes of this.