简介：BACKGROUND:Theintegrityofthebloodbrainbarrier(BBB)playsanimportantroleinthepatho-physiologicalprocessofcerebralischemia/reperfusioninjury.Ithasbeenrecentlyobservedthatmetalloproteinase-9(MMP-9)iscloselyrelatedtocerebralischemia/reperfusioninjuryOBJECTIVE:ThisstudywasdesignedtoobserveMMP-9expressionintheratbrainaftercerebralischemia/reperfusioninjuryandtoinvestigateitscorrelationtoBBBpermeability.DESIGN,TIMEANDSETTING:Thisstudy,arandomizedcontrolledanimalexperiment,wasperformedattheInstituteofNeurobiology,CentralSouthUniversitybetweenSeptember2005andMarch2006.MATERIALS:NinetyhealthymaleSDrats,aged3–4months,weighing200–280g,wereusedinthepresentstudy.Rabbitanti-ratMMP-9polyclonalantibody(Boster,Wuhan,China)andEvansblue(Sigma,USA)werealsoused.METHODS:Allratswererandomlydividedinto9groupswith10ratsineachgroup:normalcontrolgroup,sham-operatedgroup,andischemiafor2hoursfollowedbyreperfusionfor3,6,12hours,1,2,4and7daysgroups.Intheischemia/reperfusiongroups,ratsweresubjectedtoischemia/reperfusioninjurybysutureocclusionoftherightmiddlecerebralartery.Inthesham-operatedgroup,ratsweremerelysubjectedtovesseldissociation.Inthenormalcontrolgroup,ratswerenotmodeled.MAINOUTCOMEMEASURES:BBBpermeabilitywasassessedbydeterminingthelevelofeffusionofEvansblue.MMP-9expressionwasdetectedbyanimmunohistochemicalmethod.RESULTS:All90ratswereincludedinthefinalanalysis.BBBpermeabilityalterationwascloselycorrelatedtoischemia/reperfusiontime.BBBpermeabilitybegantoincreaseatischemia/reperfusionfor3hours,thenitgraduallyreachedapeaklevelatischemia/reperfusionfor1day,andthereafteritgraduallydecreased.MMP-9expressionbegantoincreaseatischemia/reperfusionfor3hours,thengraduallyreacheditspeaklevel2daysafterperfusion,andthereafteritgraduallydecreased.CONCLUSION: