右美托咪定通过Toll样受体4减轻小鼠肺缺血/再灌注损伤

摘要

目的 探讨盐酸右美托咪定(Dex)对小鼠肺缺血/再灌注损伤(LIRI)的保护作用机制.方法 将野生型( WT)和Toll样受体4敲除(TLR4-/-) C57BL/6雌鼠,随机分为:假手术组(S组)、LIRI组(I/R组)、0.9% NaCl组(NS组)和Dex 干预组( D 组).肺组织 HE 染色;RT-qPCR 检测肺组织 TLR4 mRNA 的表达;ELISA 检测肺组织中TNF-ɑ、IL-6和IL-1β(WT和TLR4--)水平;Western blot检测肺组织Nod样受体蛋白3(NLRP3)炎性小体表达量.结果 Dex明显改善WT小鼠肺缺血/再灌注病理损伤,显著降低其肺组织中TLR4表达和多种前炎性因子的产生(P＜0.01),抑制NLRP3炎性小体的产生和活化(P＜0.01).但是在TLR4--小鼠中未观察到对各种炎性因子的抑制作用.结论 Dex可通过抑制TLR4的表达,减少前炎性因子释放和NLRP3炎性小体的形成与活化,达到保护LIRI的作用.%Objective To investigate the protective mechanism of dexmedetomidine ( Dex) hydrochloride to lung ischemia/reperfusion injury ( LIRI) in mice. Methods The wild type ( WT) and Toll-like receptor 4 knockout ( TLR4-/-) C57BL/6 Balb/c female mouse randomly divided into four groups: sham group ( S group) , pulmona-ry ischemia/reperfusion group ( I/R group) , normal saline group ( NS group) and Dex group ( D group) . In S group, the chest was opened only, but in I/R group, NS group and D group, model of lung ischemia/reperfusion injury in mice was made by clamping left pulmonary hilum for 30 min, and then reperfusion for 3 h. The lung tis-sue was observed by HE staining. RT-qPCR detected the expression of TLR4 mRNA, and ELISA measured the TNF-α, IL-6 and IL-1 levels, including WT and TLR4-/-. Western blot measured the expression of NLRP3 in lung tissue in both WT and TLR4-/-. Results Dex significantly decreased the pathological damage of LIRI, re-duced the expression of levels of TLR4 mRNA and the production of inflammatory cytokines ( P＜0.01) , and also suppress production and activation of NLRP3 ( P＜0.01) in lung ischemia/reperfusion tissue in WT mice. But no cytokines was found to be inhibited in TLR4-/- mice. Conclusions Dex may decrease the release of a variety of pro-inflammatory factors and inhibit production and activation of NLRP3 inflammasome by TLR4, thereby protect lung against LIRI.