巨噬细胞游走抑制因子在人牙髓中的表达及对牙髓细胞增殖的影响

Macrophage migration-inhibitory factors expression and its effects on proliferation in human dental pulps

目的研究正常及炎症牙髓组织中巨噬细胞游走抑制因子（macrophage migrationinhibitory factors，MIF）的表达及其对人牙髓细胞（human dental pulp cells，HDPC）增殖的影响，以期探讨MIF在牙髓炎症中的可能作用。方法采用免疫组织化学和实时荧光定量聚合酶链反应（PCR）法检测健康及炎症牙髓组织中MIF的表达情况，并以不同质量浓度[0（对照组）、0．1、1．0、10．0mg／L]脂多糖刺激HDPC24h，ELISA法检测HDPC培养上清液中MIF含量的变化；不同质量浓度（10、30、60ug/L）的重组人MIF分别作用于HDPC24和48h，细胞计数试剂盒法检测细胞增殖率。结果健康牙髓组织中MIF主要分布于成牙本质细胞层，炎症牙髓组织中MIF分布于成牙本质细胞、炎症细胞、牙髓成纤维细胞和血管内皮细胞中；MIFmRNA在正常牙髓组织和炎症牙髓组织中的表达差异无统计学意义（P〉0．05）；不同质量浓度脂多糖刺激HDPC后对照组MIF质量浓度为（1048．53±161．81）ng／L，0．1和1．0mg／L组MIF分泌量[分别为（1772．58±495．05）、（1692．58±337．45）ng／L]与对照组相比均显著升高（P〈0．05），约为对照组的1．5倍；10、30、60ug/L重组人MIF均可促进HDPC的增殖（P〈0．05）。结论MIF在人牙髓组织中有表达且一定浓度脂多糖可促进HDPCMIF的分泌，重组人MIF可促进HDPC增殖，MIF可能在牙髓炎症发展过程中发挥一定作用。

Objective To investigate the expression of macrophage migration-inhibitory factors （MIF） in clinically healthy and inflamed human pulp tissues and the effects of rhMIF on the proliferation of human dental pulp cells （HDPC）. Methods Immunohistochemistry was used to detect the localization of MIF expression in clinically healthy pulp and inflamed pulp tissues. Quantitative real-time polymerase chain reaction（PCR） was performed to evaluate the mRNA levels of MIF in pulp specimens. In addition, the culture supernatants of HDPC were collected after HDPC was stimulated by lipopolysaccharide （LPS） for 24 h, and then the MIF levels were assayed by quantitative sandwich enzyme-linked immunosorbent assay. Meanwhile, the effects of rhMIF on the proliferation of HDPC at different concentrations for 24 and 48 h were observed by cell counting kit-8 （CCK-8）. Results MIF was mainly distributed in odontoblasts of healthy pulp tissue, however, in inflamed pulp tissue, it was widely detected in fibroblasts, inflammatory infiltrates and endothelial ceils as well as odontoblasts. Quantitative real-time PCR showed that there was no significant difference in MIF mRNA levels between inflamed pulps and healthy pulps （P 〉 0. 05）. Additionally, the secretion of MIF was significantly increased by stimulation with LPS at the concentration of 0. 1 and 1.0 mg/L[ （ 1772. 58 ± 495. 05）, （ 1692. 58 ± 337. 45） ng/L] （P 〈 0. 05） , and the concentration was （ 1048.53 ± 161.81 ） ng/L in control group, rhMIF stimulated the HDPC＇s proliferation at the concentration of 10,30,60 ug/L for 24 and 48 h. Conclusions MIF was expressed in pulp tissue and its expression was increased after stimulation by LPS. rhMIF increased the proliferation of HDPC. These results suggest that MIF may be involved in the process of pulpal inflammation.