髓系触发受体-1在脆弱类杆菌诱导小鼠脓毒血症中的作用

Effect of TREM-1 in sepsis caused by bacteroides fragilis in mice

目的探讨小鼠TREM-1基因重组慢病毒干扰载体(Lentivector,LV)TREM-1 vshRNA对脆弱杆菌脓毒血症小鼠脾脏中促炎症因子TNF-α,IL-1β,IL-6表达及NF-κB通路的影响。方法将清洁级BALB/c雄性小鼠分成4组,即正常对照组(C组),脆弱类杆菌脓毒症模型生理盐水组(S组),TREM-1 vshRNA干扰实验组(T组)和GFPvshRNA干扰实验组(G组)。观察各组中小鼠脾内TREM-1,TNF-α,IL-1β,lL-6的蛋白表达以及IkBa,pDAP12,NF-κB p65的表达情况的变化。结果与C组比,T组TREM-1 mRNA及蛋白表达均有显著增加(P<0.01);T,G,S组脾细胞中TNF-α,IL-1β,IL-6的含量均较C组显著增加(P<0.01);T组脾细胞中TNF-α,IL-1β,IL-6的含量均较S,G组明显降低(P<0.01)。S组脾细胞中的pDAP12和核内NF-κB p65蛋白表达水平明显增强,IκBa蛋白表达水平降低;而T组与S组比较,pDAP12和NF-κB p65蛋白的表达水平显著下调。结论小鼠TREM-1基因重组慢病毒干扰载体可选择性抑制TREM-1表达,下调脆弱类杆菌诱导的促炎症因子的分泌,而转染可能是通过下调DAP12的表达,稳定IkBa/NF-κB复合物,抑制TNF-α,IL-1β,IL-6,IL-8基因的转录,而对脆弱类杆菌脂多糖炎症反应产生抑制作用。

Objective To explore the effect and the mechanism of TREM- 1 vshRNA in the form of sepsis in mice caused by live bacteroides fragilis and the expression of TNF-α, IL-1β, IL-6 and IL-8. Methods Male mice （ BALB/c ） were randomly divided into 4 groups ： positive control （ group C ） , saline （ group S ） , TREM-1 vshRNA（ group T ） and GFPvshRNA control vshRNA （group G ） groups. Bacteroides fragilis （25mg/ kg） was injected via caudal veins in each group to establish the murine septic model. The expression of TREM-1, tumor necrosis factor alpha （TNF-α） , IL-1β,1L-6, IkBa, pDAP12 and NF-KBp65 in spleen was observed in each group. Results In comparison with group C there was marked elevation of expession of TREM-1 mRNA and protein in group T （ P 〈 0.01 ） . Compared to group C there was marked elevation of TNF-α, IL-1β and IL-6 content in splenic cells of groups T, G and S （P 〈 0.01 ）. The level of TNF-α, IL-1β and IL-6 in splenic cells of group T was markedly lower than that of groups S and G （P 〈0.01 ）. In splenic ceils of group S, pDAP12 and NF-κBP 65 protein expression was markedly increased compared to group T ; the expression of 1 κBa protein in splenic cells of groups was decreased. Conclusions The interference of TREM-1 signal pathway by TREM-1 vshRNA may inhibit the genetic transcriptions of inflammatory factors, such as TNF-α, IL-1β , IL-6 by downregulating the expression of DAP12, so to stablize the compound of IkBa/NF-κB, can inhibit the inflammatory reaction induced by Bacteroides fragilis.