中文摘要：

目的 明确人根尖牙乳头干细胞（stem cells from apical papilla,SCAP）中基质细胞衍生因子1（stromal cell-derived factor-1,SDF-1）的表达及脂多糖对其表达的影响.方法 分离培养18～24岁供者牙根未发育完全的人第三磨牙SCAP.实验分组：对照组加入细胞培养液,实验组加入含有大肠杆菌脂多糖的培养液,脂多糖终质量浓度分别为0.1、1.0及10.0 mg/L.采用细胞计数（cell counting kit-8,CCK-8）法检测脂多糖对SCAP增殖的影响,反转录PCR法检测SDF-1 mRNA在SCAP中的表达,实时PCR法检测24及48 h时脂多糖对SDF-1表达的影响.结果 脂多糖组细胞吸光度值（A值）与对照组在培养的前5天差异均无统计学意义,至第7天时脂多糖组细胞A值随脂多糖浓度增加显著降低;SCAP表达SDF-1 mRNA.在培养24 h时,0.1、1.0及10.0 mg/L脂多糖组SCAP中SDF-1mRNA的相对表达量分别为1.4±0.1、2.2±0.4及2.3±0.5,与未经脂多糖处理的对照组（设为1.0）相比差异均有统计学意义（F=12.102,P=0.002）;48 h时0.1、1.0及10.0 mg/L脂多糖组SDF-1表达量（分别为2.1±0.4、3.4±0.3、3.8±0.5）随脂多糖浓度增加而升高的趋势愈加显著,与对照组相比差异均有统计学意义（F=39.054,P＜0.001）.结论 SCAP具有趋化因子SDF-1的表达,脂多糖可在一定范围内刺激SDF-1的表达显著上调.

英文摘要：

Objective To investigate the expression of stromal cell-derived factor-1（SDF-1） in human stem cells from apical papilla（SCAP）,and to evaluate the effect of lipopolysaccharide（LPS） on SDF-1 expression by SCAP.Methods SCAP were isolated from dental papilla of human immature third molars.The expression of SDF-1 was evaluated by reverse transcription-PCR（RT-PCR）.After SCAP being exposed to different concentrations（0.1,1.0,10 mg/L） of LPS for 24 and 48 h,the effect of LPS on cell proliferation and gene expression of SDF-1 was investigated by cell counting kit-8 and real-time PCR respectively,while cells without LPS stimulation were considered as negative control.Results LPS had no significant effect on SCAP proliferation until day 7.RT-PCR assays demonstrated that SCAP expressed SDF-1 mRNA.Different concentrations of LPS significantly promoted the SDF-1 expression in SCAP after 24 h（F=12.102,P=0.002） and 48 h（F=39.054,P〈0.001） exposure,with relative gene expression ratio（experimental/control） increased to 1.4±0.1,2.2±0.4,2.3±0.5 in 24 h group and 2.1±0.4,3.4±0.3,3.8±0.5 in 48 h group.Conclusions Isolated SCAP in cultures have the expression of SDF-1 mRNA.LPS can significantly promote the expression of SDF-1 in SCAP.