LPS调控人牙髓细胞矿化中PI3K信号分子作用机制的体外研究

A in vitro study on the mechanism of PI3K signaling in the mineralization of LPS regulated human dental pulp cells

目的:研究磷脂酰肌醇-3-激酶(phosphatidylinositol 3-kinase,PI3K)信号分子在细菌脂多糖(lipopolysaccharide,LPS)调控人牙髓细胞(human dental pulp cells,hDPCs)矿化中的作用机制。方法:以改良组织块培养法获得hDPCs,采用碱性磷酸酶(alkaline phosphate,ALP)染色和茜素红染色观察LPS对hDPCs的矿化作用以及PI3K信号分子的特异性抑制剂LY294002对其的影响;通过实时定量聚合酶链反应(Real-TimePCR)检测LPS调控的hDPCs中细胞外基质矿化相关基因的表达变化。结果:矿化诱导hDPCs 4周,LPS组的ALP染色和茜素红染色均明显强于对照组,而LY294002+LPS组弱于LPS组;LPS组的矿化蛋白OCN、BSP、Collagen-I mRNA表达水平均明显高于对照组和LY294002+LPS组(P<0.05),其中LY294002+LPS组各基因表达水平均最低,但与对照组相比无统计学差异(P>0.05)。结论:PI3K信号途径参与LPS调控的hDPCs矿化过程,其机制与调节OCN、BSP、Collagen-I基因表达有关。

AIM： To investigate the mechanism of phosphatidylinositol 3-kinase（PI3K） on the mineraliza- tion of lipopolysaccharide （LPS） -regulated human dental pulp cells （hDPCs）. METHODS：hDPCs were cultured by modified tissue explant technique in vitro. ALP staining and Alizarin red staining were performed respectively to exam- ine the mineralization of LPS-stimulated hDPCs cultured with or without PI3K special inhibitor, LY294002. Real-Time PCR was used to assay the expression of odontoblastic genes. RESULTS ： After 4 weeks of osteogenic induction, ALP staining and alizarin red staining in LPS - stimulated hDPCs were much stronger than in the control cells, however, LY294002 could attenuate LPS-induced mineralization. The mRNA expressions of OCN, BSP and collagen-I in LPS- stimulated hDPCs were higher than in control cells and LY294002 ＋ LPS co-stimulated cells （P 〈 0.05）, and expres- sions of OCN, BSP and collagen-I genes in LY294002 ＋ LPS co-stimulated cells were the least, but showed no signifi- cant difference compared with controls （P 〉 0.05）. CONCLUSION： PI3K is involved in LPS-regulated mineraliza-tion of hDPCs by modulation of OCN, BSP and Collagen-I expression.