TLR4/MyD88依赖性通路和Caveolin-1的表达与2型糖尿病神经病变患者炎症状态的相关性

Study on the expression of TLR4/MyD88-dependent pathway molecules and Caveolin-1 in monocytes and their relationship with inflammatory conditions in type 2 diabetes patients with peripheral neuropathy

目的探讨单核细胞Toll样受体4(TLR4)/下游髓样分化蛋白(MyD88)依赖性通路和陷窝蛋白-1(Caveolin-1)的表达与2型糖尿病神经病变患者炎症状态的相关性。方法 120例受试者均分为三组:健康志愿者组(NC组)、2型糖尿病不伴有神经病变组(TDM组)和2型糖尿病伴有神经病变组(DPN组);单次抽取各研究对象清晨空腹血8ml;应用密度梯度离心法分离和提取外周血单核细胞;分别通过RT-PCR检测Caveolin-1mRNA和TLR4表达,Western blot检测Caveolin-1和TLR4及其下游信号(MyD88、IκB、p-IκB)蛋白表达,ELISA检测血浆肿瘤坏死因子α(TNF-α)和白细胞介素-6(IL-6)的水平。结果与TDM和NC组比较,DPN组患者血浆TNF-α、IL-6和TLR4及其下游信号蛋白表达明显增加(P<0.05),而Caveolin-1表达明显降低(P<0.05);Spearman相关性分析显示TLR4mRNA与TNF-α(r=0.723,P<0.01)和IL-6(r=0.486,P<0.01)呈正相关,且与TNF-α密切程度高于IL-6,与Caveolin-1mRNA呈负相关(r=-0.782,P<0.01)。结论 DPN患者炎症状态与单核细胞TLR4/MyD88依赖性通路介导的炎症级联反应相关;低表达的Caveolin-1与DPN患者TLR4/MyD88依赖性通路异常活化有关。

Objective To measure the expression of toll-like receptor 4（TLR4）/MyD88-dependent pathway molecules and Caveolin-1,and explore the relationship between TLR4,Caveolin-1and inflammatory conditions in type 2 diabetes patients with peripheral neuropathy（DPN）.Methods One hundred and twenty individuals were divided into three groups（n=40）：healthy volunteers（NC）group,type 2diabetes patients without peripheral neuropathy（TDM）group and DPN group.Early in the morning,8ml of venous blood specimen was drawn from every single subject in a fasting state.Peripheral blood mononuclear cells（PBMCs）were isolated with Ficoll-Hypaque density-gradient centrifugation.Expression of Caveolin-1,TLR4/MyD88-dependent pathway molecules in freshly isolated monocytes as well as TNF-αand IL-6were measured with RT-PCR,Western blotting and ELISA,respectively.Results Expression of TNF-α,IL-6and TLR4/MyD88-dependent pathway molecules in group DPN were higher than those in group TDM and group NC but Caveolin-1mRNA levels were significantly lower（P〈0.01）.A positively linear correlation between the levels of plasma TNF-α（r=0.723,P〈0.01）and TLR4 mRNA was observed in patients with DPN（P〈0.01）,which was weaker between IL-6（r=0.486,P〈0.01）.TLR4 mRNA showed a negative correlation with Caveolin-1（r=-0.782,P〈0.01）.Conclusion Our results indicate that TLR4/MyD88-dependent signaling pathway mediated synthesis and release of inflammatory cytokines in monocytes is implicated in inflammation conditions in DPN and a reduction in Caveolin-1contributes to the abnormal activation of TLR4/MyD88-dependent pathway molecules.