内毒素血症大鼠膈肌iNOS活性和凋亡相关基因表达的变化  

The changes of inducible nitric oxide synthase activity and apoptosis-related gene expression in endotoxemia-induced rat diaphragm

作　　者：方迎艳[1] 关宿东[1] 郭晓磊[1] 叶红伟[1] 汪华学[2] 高琴[1] 

机构地区：[1]蚌埠医学院生理学教研室,安徽蚌埠233030 [2]蚌埠医学院第一附属医院ICU,安徽蚌埠233004

出　　处：《中国应用生理学杂志》2013年第3期209-212,共4页Chinese Journal of Applied Physiology

基　　金：国家自然科学基金项目(81000074);安徽省高等学校省级自然科学研究项目(KJ2012Z254);蚌埠医学院科技发展基金项目(Bykf12B19)

摘　　要：目的:观察内毒素血症大鼠膈肌诱导型一氧化氮合酶(iNOS)活性及凋亡相关基因Bc-l 2、Bax和caspase-3mRNA表达的变化,探讨内毒素血症大鼠膈肌损伤的细胞凋亡机制。方法:32只雄性SD大鼠随机分成4组(n=8):生理盐水对照组和内毒素24 h、48 h和96 h组,即内毒素12 mg/kg腹腔注射,分别于注射内毒素后24 h、48 h、96h处死大鼠,测定大鼠体重和膈肌重/体重比值,检测膈肌组织结构型NOS(cNOS)、iNOS和琥珀酸脱氢酶(SDH)活性,RT-PCR检测大鼠膈肌凋亡相关基因Bc-l 2、Bax和caspase-3 mRNA的表达。结果:与正常对照组比较,内毒素血症96 h组大鼠体重和膈肌重/体重比值明显降低(P<0.05);膈肌组织cNOS和iNOS活性明显增强,96 h组较48 h、24 h组显著升高(P<0.01);SDH活性明显降低,96 h组较48 h、24 h组明显降低(P<0.01);Bax mRNA表达明显增强,48 h、96 h组较24 h组明显增强;Bc-l 2mRNA表达及Bc-l 2/Bax比值明显降低,48 h、96 h组较24 h组明显降低(P<0.01);caspase-3 mRNA表达显著增强,48 h、96 h组较24 h组明显增强(P<0.01)。结论:内毒素血症大鼠膈肌组织iNOS的激活,损伤线粒体,上调促凋亡基因Bax,下调抑凋亡基因Bc-l 2,启动经caspase-3细胞凋亡途径,导致膈肌损伤和萎缩。Objective： To study the changes of inducible nitric oxide synthase（iNOS） activity and apoptosis-related genes Bcl-2,Bax and caspase-3 mRNA expressions in endotoxemia-induced rat diaphragm injury and analyze the related apoptosis mechanism.Methods： Thirty-two male SD rats were randomly divided into 4 groups（n=8）： control group（saline 0.5 ml ip）,endotoxin 24 h,48 h and 96 h group（endotoxin 12 mg/kg ip,animals were killed either 24,48 or 96 h after injections）.Body weight were measured,the ratio between diaphragm weight and body weight,activities of constitutive nitric oxide syntheses（cNOS）,iNOS and succinate dehydrogenase（SDH） were also measured.The expressions of Bcl-2,Bax and caspase-3 mRNA were detected by RT-PCR analysis.Results： Endotoxin induced significant reductions in diaphragm mass in endotoxin 96 h group（P0.05）.Endotoxin increased diaphragm cNOS or iNOS activities,and they were significantly higher in endotoxin 96 h group than those in endotoxin 24 h and 48 h groups,diaphragm SDH activity was reduced,and it was lower in endotoxin 96 h group than that in endotoxin 24 h and 48 h groups（P0.01）.Endotoxin significantly increased Bax and caspase-3 mRNA expressions,and they were higher in endotoxin 48 h and 96 h groups than those in endotoxin 24 h group（P0.01）.Endotoxin significantly reduced Bcl-2 mRNA expression and the ratio of Bcl-2/Bax,and they were lower in endotoxin 48 h and 96 h groups than those in endotoxin 24 h group（P0.01）.Conclusion： iNOS is activated in endotoxemia-induced rat diaphragm injury.It damages mitochondria,upregulates Bax expression and downregulates Bcl-2 expression,then induces caspase-3 related apoptotic pathway.These changes may cause diaphragm injury and atrophy.

关 键 词：内毒素血症 膈肌 诱导型一氧化氮合酶 Bc-l2 Bax caspase-3 

分 类 号：R363.2[医药卫生—病理学]