BACKGROUND:Studieshavedemonstratedthatthemechanismsunderlyingcellularapoptosissignaltransductionfocusontwopathways:intracellularmitochondriaandextracellulardeathreceptor.Thecurrentevidencesupportsthatsignaltransductionofcellularapoptosisalsoincludesendoplasmicreticulumstresssignaltransduction.OBJECTIVE:ToobserveCaspase-12expressionandcellularapoptosisfollowingischemiainratswithprogressivespinalcordcompression,andtoverifytheinfluenceofendoplasmicreticulumstressontheapoptosisinducedbyspinalcordinjury.DESIGN,TIMEANDSETTING:Arandomized,controlled,animaltrialwasperformedattheInstituteofNeuroscienceinChongqingMedicalUniversitybetweenJanuaryandOctoberin2006.MATERIALS:Immunohistochemicalkit,diaminobenzidine,andTUNELkitwerepurchasedfromBeijingZhongshanBiotechnology,China;rabbitanti-ratCaspase-12monoclonalantibodywasprovidedbySantaCruz,USA.METHODS:SixtyWistarrats,aged3-4months,wererandomlyassignedtoamodelgroup(n=50),whichunderwentspinalcordcompressionintheL_1segmentfollowingL_1laminectomyandarticularprocessexcisiontoestablishamodelofprogressivespinalcordcompression,andasham-surgerygroup(n=10),whichunderwentonlylaminectomy.Startingwiththefirstdayaftersurgery,theratswerelocallyanesthetized,theskinwasopened,andthescrewwasrotatedby1/4ofacycle,twiceweekly.MAINOUTCOMEMEASURES:At3,7,14,21,and28daysaftersurgery,ratsfromeachgroupwereanesthetized,andthespinalcordswereresected.Pathologicalchangesfollowingspinalcordcompressionweredeterminedusinghematoxylin-eosinstaining,Nissldye,andtransmissionelectronmicroscopy.TheTUNELmethodwasusedtoobserveneuronalapoptosisinthecompressedspinalcordsegments.ImmunohistochemistryandWesternblotwereutilizedtodetectCaspase-12expressioninthecompressedsegments.RESULTS:Cellularswelling,neuraldegeneration,andalteredendoplasmicreticulumstructureswereobservedat3days
