高氧预适应对大鼠心肌缺血损伤时抗氧化酶的影响

抗氧化酶具有减轻心肌缺血再灌注损伤的作用，在抗氧化酶中，比较重要的是超氧化物歧化酶（ＳＯＤ），谷胱甘肽过氧化物酶（ＧｌｕｔａｔｈｉｏｎｅＰｅｒｏｘｉｄａｓｅ，ＧＳＨｐｘ）和过氧化氢酶（ＣＡＴ）。为了解高氧预适应（ＨｙｐｅｒｏｘｉｃＰｒｅｃｏｎｄｉｔｉｏｎｉｎｇ，ＨＯＰ）对大鼠心肌缺血损伤时抗氧化酶的影响，本实验将实验组大鼠放入高压氧舱内，每日吸８０－８５％氧气（１ａｔｍ，１５－２０％为氮气）６ｈ，连续７ｄ。利用Ｌａｎｇｅｎｄｏｒｆ装置做成心肌缺血再灌注模型。实验动物随机分为二个部分。第一部分可逆性心肌缺血（ＨＯＰＡ组与对照Ａ组）：缺血１０ｍｉｎ，再灌注６０ｍｉｎ。观察冠脉回流液中ＳＯＤ活力，检测心肌内抗氧化酶活力（ＳＯＤ，ＧＳＨｐｘ，ＣＡＴ）。第二部分不可逆性心肌缺血（ＨＯＰＢ组与对照Ｂ组）：缺血６０ｍｉｎ，再灌注６０ｍｉｎ。测定冠脉回流液中肌酸磷酸激酶（ＣＰＫ）含量，ＳＯＤ及心肌内抗氧化酶活力。结果表明：对于可逆性心肌缺血：ＳＯＤ，ＧＳＨｐｘ活力升高；对于不可逆性心肌缺血损伤：ＨＯＰ能减少ＣＰＫ释放，ＳＯＤ活力升高。

EFFECTSOFHYPEROXICPRECONDITIONINGONANTIOXIDANTENZYMESINMYOCARDIALISCHEMIAINJURYINRATS

Inordertoinvestigatetheefectsofhyperoxicpreconditioning(HOP)onmyocardialischemiain juryandantioxidantenzymesinisolatedratheartswerestudiedwithLangendorfmethod.RatswererandomlydividedintoHOPgroups(exposedto80-85%O2,1atm,sixhourseachdayforsevendaysbeforetheexperiment)andcontrolgroups(exposedtoroomairfor7daysbeforetheexperiment).Theratheartsunderwent10minischemiafolowedby60minreperfusioninHOP A(reversiblemy ocardialischemia,n=5)andcontrolA(n=5)groups,and60minischemiafolowedby60minreper fusioninHOP B(ireversiblemyocardialischemia,n=5)andcontrol B(n=5)groups.CPK,theac tivitiesofSODincoronaryefluentandSOD,glutathioneperoxidase(GSH px)andcatalase(CAT)inmyocardiumweremeasured.TheresultsshowedthatCPKinHOP Bgroupincoronaryefluentweresignificantlylesthanthatincontrolgroupafterreperfusion,andtheactivitiesoftheantioxidanten zymsSOD,GSH pxinmyocardiumweresignificanflyhigherinbothHOP AandBgroupsthanthatincontrolgroups.CATdidnotshowstatisticaldiferencebetweenthetwogroups.Theresultsindi catedthatHOPmayplayaprotectiveroleonmyocardialischemiainjury.