内毒素耐受状态小鼠对大肠埃希菌敏感性及促炎细胞因子水平变化的研究  

The sensitivity of LPS tolerance mice to Escherichia coli is mediated through modulation of pro-inflammatory cytokine release

作　　者：李攀[1] 赵祎博 李小丽[1] 李斌[1] 周红[1] 

机构地区：[1]第三军医大学药学系药理学教研室,重庆400038

出　　处：《中国临床药理学与治疗学》2015年第3期261-265,326,共6页Chinese Journal of Clinical Pharmacology and Therapeutics

基　　金：第三军医大学科技成果转化基金项目(2013XZH03)

摘　　要：目的:研究内毒素耐受状态对大肠埃希菌的敏感性及促炎细胞因子水平的变化。方法:采用小剂量LPS(1mg/kg)连续腹腔注射5d并在第6天尾静脉注射大剂量LPS(50mg/kg)建立小鼠内毒素耐受模型。观察小鼠7d存活率或采用ELISA法检测注射大剂量LPS后6、12h血清中TNF-α、IL-6水平。然后,采用不同浓度的大肠埃希菌攻击耐受小鼠,观察小鼠7d存活率;或采用血培养方法检测血液中细菌数量,ELISA法检测血清中TNF-α、IL-6水平。结果:大剂量LPS攻击组(攻击组)小鼠存活率为0%,LPS耐受组(耐受组)小鼠存活率为100%;耐受组小鼠血清TNF-α、IL-6水平较攻击组显著降低(P<0.01)。5.0×108 CFU/kg大肠埃希菌可导致正常小鼠100%死亡,但是仅1.0×107 CFU/kg大肠埃希菌就可导致耐受组小鼠100%死亡;耐受组给予大肠埃希菌低、高剂量组小鼠血液中细菌数量远远高于相应的正常小鼠大肠埃希菌低或高剂量组(P<0.01),而血清中TNF-α、IL-6水平则远远低于相应的大肠埃希菌低或高剂量组(P<0.01)。结论:连续腹腔注射小剂量LPS 5d后并在第6天尾静脉注射大剂量LPS可成功建立LPS耐受模型;与正常对照组小鼠比较,较低数量的大肠埃希菌就可导致耐受组小鼠死亡,说明内毒素耐受小鼠对大肠埃希菌的敏感性较正常小鼠明显增高,其机制可能与内毒素耐受后促炎细胞因子水平降低、机体抵抗力降低有关。AIM：To study the sensitivity of LPS tolerance mice to Escherichia coli（E.coli）and the change of its pro-inflammatory cytokines.METHODS：Mice were intraperitoneally injected 1mg/kg LPS for 5days and then intravenously injected with 50 mg/kg LPS on the sixth day to establish LPS tolerance mice model.In this model,the seven days＇ survival rate was observed or serum TNF-α,IL-6levels at 6h,12 h after injection of 50mg/kg LPS were detected by ELISA assay.Then different concentration of E.coli were intraperitoneally administrated,the seven days＇ survival rate was observed,bacterialloads in blood were counted and serum TNF-α,IL-6levels were detected.RESULTS：The survival rate of 50 mg/kg LPS attack group was0%,however,the survival rate of LPS tolerance mice was 100%.The serum TNF-αand IL-6levels in LPS tolerance group were obviously lower than those of 50mg/kg LPS attack group（P〈0.01）.Only 1.0×10^7 CFU/kg of E.coli could lead to 100% death in LPS tolerance mice,while in normal control mice it was 5.0×10^8CFU/kg of E.coli.The blood bacterial load of LPS tolerance mice suffered fromE.coli hit was much higher than that of only E.coli attack mice（P〈0.01）.The serum TNF-αand IL-6levels were much lower in LPS tolerance mice suffered with E.coli hit compared to only E.coli attack mice（P〈0.01）.CONCLUSION：LPS tolerancemice model could be successfully established by intraperitoneal injection of 1 mg/kg LPS for 5consecutive days and then intravenous injection of 50mg/kg LPS on the sixth day.A lower concentration of E.coli could lead to LPS tolerance mice death,the results suggest that the sensitivity of LPS tolerance mice to E.coli significantly increased compared to normal mice,and the mechanism might be closely associated with the reduction of pro-inflammatory cytokine levels leading to decrease the body＇s resistance.

关 键 词：脓毒症 内毒素耐受 大肠埃希菌 细菌数量 促炎细胞因子 

分 类 号：R965.2[医药卫生—药理学]