基质细胞衍生因子1α及其受体CXCR4在人牙髓细胞中的表达

目的 研究体外培养人牙髓细胞(human dental pulp cells,HDPC)上CXCR4的表达情况,检测大肠杆菌脂多糖(lipopolysaccharide,LPS)和肿瘤坏死因子α(TNF-α)刺激后HDPC培养上清液中基质细胞衍生因子1α(stromal cell-derived factor-1α,SDF-1α)的表达水平,探讨人工重组SDF-1α(recombinant human SDF-1α,rhSDF-1α)对HDPC增殖及迁移的影响.方法 采用免疫细胞化学及间接免疫荧光技术检测HDPC上CXCR4的表达.用不同浓度LPS(0.1、1、10、100 mg/L)和TNF-α(1、10、100μg/L)刺激HDPC 48 h后,ELISA法检测HDPC培养上清液中SDF-1α含量的变化.同时甲基噻唑基四唑(MTT)法及体外趋化实验观察不同浓度rhSDF-1α对HDPC增殖及迁移的影响.结果 正常HDPC胞膜表达CXCR4且其培养上清液分泌SDF-1α,浓度约为(4513.55±962.92)ng/L.在用LPS和TNF-α刺激HDPC后,SDF-1α的表达水平均显著降低(P＜0.05).50、100和200μg/L的rhSDF-1α可促进HDPC的增殖(P＜0.05),50和100μg/L rhSDF-1α作用9 h可显著趋化HDPC的迁移(P＜0.01).结论 CXCR4在HDPC上表达且SDF-1α能促进HDPC的增殖及迁移;SDF-1-CXCR4轴可能在牙髓组织损伤修复中发挥重要作用.

Expression and significance of stromal cell-derived factor-1α and its receptor CXCR4 in human dental pulp cells

Objective To investigate the expression of CXCR4 in cultured human dental pulp cells (HDPC) in vitro and the corresponding ligand SDF-1α level of HDPC supernatants stimulated by lipopolysaccharide(LPS)and tumor necrosis factor-α(TNF-α),and to explore the role of SDF-1αon the proliferation and the migration of HDPC.Methods The expression of CXCR4 in HDPC was detected by immunocytochemistry technique and indirect immunofluorescence technique.The culture supernatants of HDPC were collected after HDPC had been simulated by LPS and TNF-α of difierent concentrations for 48h and then the SDF-1α level was assayed by quantitative sandwich ELISA.Meanwhile,the effects of recombinant human SDF-1α(rhSDF-1α)on the proliferation and the migration of HDPC at different concentrations were observed by MTT and Boyden Chamber Assay.Results CXCR4 was expressed in cytomembrane of HDPC and SDF-1α was secreted into their normal cell supematants with a concentration of(4513.55±962.92)ng/L. The secretion of SDF-1α was both significantly decreased by stimulation with LPS and TNF-α(P＜0.05).In addition,rhSDF-1α stimulated the HDPC proliferation at the concentrations of 50,100,200μg/L(P＜0.01)and increased the chemotactic migration of HDPC significantly after 9h's incubation with the concentrations of 50,100μg/L(P＜0.05).Conclusions SDF-1α accelerated the proliferation and the migration of HDPC which expressed CXCR4.SDF-1-CXCR4 axis may play a role in repair of pulp injury.