牙龈卟啉单胞菌脂多糖对单核细胞THP-1表达CC类趋化因子受体2的影响

Effect of Porphyromonas gingivalis lipopolysacchearide on the expression of CC chemokine receptor 2in monocytes

目的研究牙龈卟啉单胞菌脂多糖（Porphyromonas gingivalis lipopolysacchearide，Pg-LPS）对单核细胞THP-1表达CC类趋化因子受体2（ CC chemokine receptor 2, CCR2）的影响，从分子水平探讨牙周炎与心血管疾病之间的关系。方法采用不同质量浓度[0μg／L（空白对照组）、10μg/L（T1组）、100μg／L（T2组）、1000μg/L（T3组）]Pg-LPS处理THP-1细胞1、4和24h，流式细胞术和实时荧光定量PCR法检测THP-1表达CCR2蛋白和mRNA的变化。结果除1h的T1组CCR2受体蛋白表达量（55．74±0．96）外，所有实验组不同时间点CCR2的蛋白和mRNA表达水平均显著高于空白对照组（P〈0．05）；24h时T1-T3组CCR2的蛋白表达量（52．56±0．61、40．98±0．86、26．50±0．67）和mRNA表达量（0．095±0．006、0．070±0．004、0．046±0．004）均显著低于空白对照组CCR2蛋白和mRNA表达（56．99±0．44、0．104±0．003），差异均有统计学意义（P〈0．05）；所有实验组CCR2蛋白和mRNA表达水平均在4h时增加，24h时降低，与空白对照组相比差异均有统计学意义（P〈0．05）。结论Pg-LPS作用于单核细胞的早期阶段，可呈浓度依赖性刺激单核细胞表面CCR2受体的表达，促进单核细胞的趋化作用；牙周致病菌导致的单核细胞趋化作用增强可能是牙周炎促进动脉粥样硬化斑块形成的原因之一。

Objective To investigate the effects of Porphyromonas gingivalis lipopolysacchearide （Pg-LPS） on the expression of CC chemokine receptor 2 （CCR2） in THP-1 monocyte and to explore the relationship between periodontitis and cardiovascular disease in molecular level. Methods THP-1 monocytes were incubated with different concentrations of Pg-LPS（ 10,100,1000 μg/L） for 1,4 and 24 h respectively, then flow cytometry and reverse transcription-PCR were adopted to determine cell surface protein levels and mRNA levels of CCR2. Results The protein levels and mRNA levels of CCR2 were higher in all experiment groups of 1 h and 4 h than that in the control group（P 〈0. 05）, except the protein expression of CCR2 in T1 group of 1 h（55.74 ± 0. 96）. The protein expression （52. 56 ±0. 61,40. 98±0. 86,26. 50±0. 67） and mRNA levels（0. 095 ±0. 006,0. 070±0. 004,0. 046 ±0. 004） of CCR2 were lower in all experiment groups than that in the control group （ 56. 99± O. 44,0. 104± 0. 003 ） at 24 h （ P 〈 0. 05 ）. The protein levels and mRNA levels of CCR2 were increased in all experiment groups at 4 h and reduced at 24 h （ P 〈 0.05 ）. Conelusions Pg-LPS can upregulate CCR2 expression on THP-1 monocyte surface in concentration dependent manner in early stage, promoting the monocyte chemoattractant. Periodontitis may promote atherosclerosis by enhancing monocyte chemoattractant through periodontal pathogens.