从树突状细胞探讨肠源性感染的成因

Dendritic cells:another possible carrier for gastrointestinal bacterial translocation

目的观察创伤后肠道树突状细胞迁移和形态变化情况,初步探讨树突状细胞和肠道细菌移位之间的关系。方法48只Wistar大鼠随机分为2组,假手术组(n=8)不放血,失血性休克组(n=40)按Wigger's法复制失血性休克模型。分别于术后3、6、12、24、48 h取肠系膜淋巴结行抗S-100免疫组化染色及细菌培养,分析各时间段系膜淋巴结内细菌和树突状细胞数量之间的变化关系。结果树突状细胞和细菌数量同时在术后12 h达到高峰,两者在时间变化上密切相关(r=0.89)。结论在创伤后肠源性感染的发生机制中,树突状细胞极有可能和巨噬细胞一样,携带活菌迁移,构成细菌淋巴途径移位的重要载体。

Objective To observetheimmigrationand morphologicalchangesof peripheraldendriticcells(DCs)after hemorrhagicshockandto understandtheroleof DCsin bacterialtranslocation(BT)fromthegastrointestinaltract.Methods Forty-eightWistarratswererandomlydividedintosham-openratedgroup(n=8)whichdidnot receivephlebotomyand hemorrhagicshockgroup(n=40)in whichhemorrhagicshockwas inducedwithWigger'smethod,withthecarotidpressure manipulatedat5.3kPafor1h beforeresuscitationby transfusionof thebloodfrompreviousphlebotomyalongwithinfusion of Ringer'ssolutionof thesamevolume.Usingsteriletechnique,themesentericlymphnodes(MLNs)weresampledat3,6,12,24and48h respectively(n=8)followingtheresuscitation,andimmunohistochemicalstudyandbacterialculturewere conducted.Results In thesham-operatedgroup,bacterialcultureyieldedonlyl positiveresults,whileinthehemorrhagic shockgroupallanimalswereshownpositivefor bacteria.The numberof DCs and amountof thebacteriain theMLNs increasedsignificantlyafterhemorrhagicshock,bothreachingthemaximumat12h ina highlycorrelativemanner(r=0.89).Morphologically,DCsinthehemorrhagicshockgroupwithabundantdendriticprocessesdifferedfromthoseofthesham-operated rats,thelatterwithscarcechangesduringtheexperiment.Conclusion Hemorrhagicshockresultsin morphologicaland functionaltransformationsof gastrointestinalDCs,thenumberof whichis inpositivecorrelationwiththeamountof bacteria intheMLN,indicatingthatDCs,besidesthemacrophages,arealsoimportantbacteriacarriersduringthegenerationof BT.