TNF-α对体外培养人牙囊细胞表达RANKL、OPG的影响

Effects of TNF-α on receptor activator of nuclear factor-kappa B ligand (RANKL) and osteoprotegerin (OPG) expression of human dental follicle cells in vitro

目的研究不同浓度的肿瘤坏死因子-α(TNF-α)对体外培养人牙囊细胞中核因子-κB受体活化子配体(RANKL)、骨保护素(OPG)mRNA表达的影响,探讨牙齿萌出过程中TNF-α对破骨细胞形成的作用。方法原代培养人牙囊细胞,取生长状态良好的第5代人牙囊细胞分别与浓度为0(对照)、5、10、25、50、100ng/ml的TNF-α共同孵育6h,提取细胞RNA,RT-PCR检测RANKL、OPG的mRNA表达。以β-actin作内参物,比较各组PCR产物的光密度比值。结果与对照组(TNF-α 0ng/ml)比较,5ng/ml TNF-α可降低人牙囊细胞中OPG的表达(P<0.05),其他不同浓度TNF-α作用后OPG的表达与对照组比较无显著性差异。TNF-α浓度为25、50、100ng/ml时RANKL的表达增强,与对照组比较有显著性差异(P<0.05)。结论TNF-α可增强人牙囊细胞RANKL的表达,降低OPG的表达,提高RANKL/OPG的比值,提示TNF-α在牙齿萌出过程中对破骨细胞的形成有重要作用。

Objective To study the effect of different concentration of tumor necrosis factor-α （TNF-α） on expression of the receptor activator of nuclear factor-kappa B ligand （RANKL） and osteoprotegerin （OPG） mRNA on human dental follicle cells in vitro, and investigate the role of TNF-α in osteoclast formation during tooth eruption. Methods The 5th passage of primary cultured human dental follicle cells were treated with 0 （control group）, 5, 10, 25, 50 and 100ng/ml TNF-α, respectively, for 6 hours. Total RNA was then isolated from human dental follicle cells and subjected to RANKL and OPG mRNA assay by reverse transcription-polymerase chain reaction （RT-PCR） technique. The relative expression levels of RANKL and OPG mRNA were normalized to β-actin gene expression. Results The mRNA expression of OPG in human dental follicle cells with 5ng/ml TNF-α treatment was down regulated significantly compared with that in control group （P〈20.05）, whereas there was no obvious reduction of OPG expression in human dental follicle cells with treatment of TNF-α in other eoncentrations. Compared with cells without TNF-α treatment, cells treated with 25, 50 and 100ng/mL of TNF-α showed a significant up-regulation of RANKL mRNA expression （P〈20.05）. Conclusions TNF-α may increase the RANKL expression, but inhibit OPG expression. The raised RANKL/OPG ratio implies that TNF-α plays an important role in stimulation of osteoclastogenesis, and TNF-α is essential for osteoclast formation during tooth eruption.