EffectofEPECendotoxinandbifidobacteriaonintestinalbarrierfunctionthroughmodulationoftoll-likereceptor2andtoll-likereceptor4expressioninintestinalepithelialcell-18

摘要： AIMToinvestigatetoll-likereceptor2(TLR2)andTLR4expression,followingbifidobacteriaandlow-doseEPECendotoxintreatment,andintestinalbarrierfunctioninratintestinalepithelialcell-18(IEC-18).METHODSSixexperimentalgroupswereestablished-normalcontrol,EPEC,Bifidobacteriainfantis(B.infantis),B.longum,B.bifidum,andB.youthgroups.OptimalEPECendotoxinconcentration,bifidobacteriafolddilution,andtreatmentdurationweredetermined.Quantitativereal-timepolymerasechainreactionandwesternblot,respectively,wereconductedtodetectTLR2andTLR4mRNAandproteinexpressioninIEC-18cells.Transepithelialelectricalresistance(TEER)wasmeasuredbytheEVOMchopstickvoltohmmeterineachgroup.AllexperimentswereconductedintriplicateanddatawereanalyzedonSPSS16.RESULTSTLR2andTLR4mRNAandproteinexpressionintheEPECgroupweresignificantlyhigherthaninthecontrolgroup(P<0.05).TLR2mRNAandproteinexpressionintheB.infantis,B.longumandB.youthgroupsweresignificantlylowerthaninthenormalcontrolgroup(P<0.05).TLR4mRNAandproteinexpressionintheB.bifidumandB.youthgroupsweresignificantlylowerthaninnormalcontrols(P<0.05).Inaddition,theTEERinB.infantis,B.longum,B.bifidum,andB.youthgroupsweredecreasedby19%,18%,23%and23%,respectively,after120minofintervention,ascomparedtothecontrolgroup.However,theTEERintheEPECgroupwassignificantlydecreasedby67%incomparisontothenormalcontrolgroup(P<0.05).CONCLUSIONBifidobacteriaprotectIEC-18cellsagainstinjurybydown-regulatingTLR2andTLR4expressionandenhanceintestinalbarrierfunctiontoprotecttheintestinalepithelialcellsfrompathogenicinvasion. ... （共8页）