1,25(OH)_2D_3对培养人牙乳头细胞Calbindin-D28K表达和矿化能力的影响

1,25(OH)_2D_3 modulation of the calbindin-D28K expression and the mineralization capability of cultured human dental papilla mesenchymal cells

目的 :研究 1,2 5 (OH) 2 D3 对培养人牙乳头细胞Calbindin -D2 8K(CaB)表达和矿化能力的影响。方法 :用 10 -8mol/L 1,2 5 (OH) 2 D3 矿化液处理长期培养的第 2 8天细胞 2 4h ,用放射免疫和免疫组化方法 ,观察CaB表达和碱性磷酸酶 (ALP)、骨钙蛋白 (OC)的变化。同位素示踪方法观察 1,2 5 (OH) 2 D3 对胞外基质4 5Ca2 + 的影响。结果 :加入1,2 5 (OH) 2 D3 后ALP活性约为对照组的 4倍 ;OC含量约为对照组的 1.5倍。CaB在培养 2 8d牙乳头细胞及其胞外基质中表达 ,而在培养 14d牙乳头细胞中CaB免疫反应阴性。 1,2 5 (OH) 2 D3 可加强CaB表达 ,并使胞外基质对4 5Ca2 + 摄取量增加 1.5倍。结论 :1,2 5 (OH) 2 D3 有促进人牙乳头细胞矿化作用 ,表现在不仅能刺激OC、ALP的活性 ,而且可刺激具有分化表型的牙乳头细胞中CaB的合成 ,增加基质对Ca2 + 的摄取。证实促进牙乳头细胞的钙转导是CaB在矿化过程中的作用之一 ,推测CaB被“俘获”在基质中时有诱导Ca2 + 聚集和直接贮存的作用。

AIM:To investigate the effects of 1,α25-dihydroxyvitamin D 3 (1,25(OH) 2D 3) on the expression of Calbindin-D28K (CaB) and mineralization capability of cultured human dental papilla mesenchymal cells. METHODS: After being incubated for 28 days, the subculture was treated with 1,25(OH) 2D 3. Ocsynthesis, ALP activity and CaB expression were measured by radioimmunoassay and immunohistochemical method. Isotope tracing study was also adopted for observing the effects of 1,25(OH) 2D 3 on calcium uptake into extracellular matrix. RESULTS: The results showed that ALP activity and OC content increased to 4 times and 1.5 times respectively in comparing with those of the control. Immunohistochemical study exhibited CaB expression in the matrix and papilla mesenchymal cells cultured for 28 days, but is negative for 14 days. The results also manifested that 1,25(OH) 2D 3 could enhance the expression of CaB and stimulate calcium uptake into extracellular matrix. CONCLUSION: These findings indicated that the 1,25(OH) 2D 3 can stimulate mineralization process of the mesenchymal cells, which is manifested in promoting ALP activity, OC content, CaB synthesis and calcium uptake by the differentiated cells. All of these further confirmed that to promote calcium transport in papilla cells is one of the functions of CaB in mineralization. It also can be inferred that the CaB could induce calcium accumulation once it is captured in the matrix. [