激动维甲类X受体抑制心肌细胞缺氧／复氧损伤  

Activating retinoid X receptor protected rat cardiomyocytes H9c2 from hypoxia/reoxygenation injury

作　　者：单培仁[1] 黄周青[1] 卜军[2] 黄伟剑[1] 

机构地区：[1]温州医科大学附属第一医院心内科,浙江省温州325000 [2]上海交通大学医学院附属仁济医院心内科

出　　处：《中华急诊医学杂志》2013年第10期1117-1122,共6页Chinese Journal of Emergency Medicine

基　　金：温州市科技局项目（Y20100010）;浙江省教育厅项目（Y200906376）;国家自然基金资助项目（81270282、81070176、30600242、81170192）;上海市曙光计划资助项目（12SG22）

摘　　要：目的探讨激动维甲类X受体（retinoid X receptor，RXR）对大鼠心肌细胞H9c2缺氧／复氧（ hypoxia-reoxygenation, H/R）损伤的保护作用及其机制。方法将心肌细胞缺氧2h／复氧4h，建立H／R损伤模型。以9-顺式维甲酸（9-cis retinoid acid, c-RA）为RXR激动剂，HX531为RXH拮抗剂，实验随机（随机数字法）分4组：健康对照组（N组）、H／R损伤组、H／R＋100nmoL／Lc-RA组（RA组）、I-I／R＋100nmo]／Lc—RA＋2．5ixmoL／LHX531组（HX组），MTT法检测细胞活性，流式细胞技术检测细胞凋亡比例，荧光探针JC-1测定线粒体膜电位，Westernblot印迹法检测Bcl-2、Bax及活性片段Caspase-9蛋白表达。所有计量资料以均数±标准差（i±5）表示，采用单因素方差分析，Dennett-t检验，以P〈0．05为差异具有统计学意义。结果c-RA明显抑制H／R损伤引起的细胞活性下降、凋亡增加、线粒体膜电位下降，Westernblot印迹检测发现，H／R损伤组Bax、Caspase-9活性片段蛋白表达明显增加，Bcl-2表达明显下降，c—RA预处理后能明显下调Bax、Caspase-9活性片段蛋白表达及上调Bcl-2表达，而所有这些保护作用均被RXR拮抗剂HX531阻断。结论激动核受体RXR可以保护心肌细胞H／R氧化应激损伤，其机制与抑制线粒体凋亡通路有关。Objective To determine the protective effects and potential mechanism of activating retinoid X receptor （ RXR ） on rat cardiomyoeytes H9c2 against hypoxia/reoxygenation （ H/R ） induced oxidative injury. Methods The model of H/R injury was established with hypoxia for 2 hours and reoxygenation for 4 hours in eardiomyocytes of H9c2, and 9-cis-retinoic acid （c-RA） was obtained as RXR agonist, and HX531 as RXR antagonist. Cultured eardiomyocytes were randomly （random number） divided into four groups： sham group, H/R group, H/R ＋ c-RA-pretreated group （ 100 nmoL/L e-RA） and H/R ＋ c-RA ＋ HX531-pretreated group （2. 5 μmoL/L HX531 ）. We measured the cell viability by MTT （methyl thiazolyl tetrazolium ）, apoptosis rate of eardiomyoeytes by using flow cytometry , and mitoehondrial membrane potential by JC-1 fluorescent probe, protein levels of Bel-2, Bax and cleaved Caspase-9 with Western blot. All measurement data were expressed as （x- ＋ s ） , and statistically analyzed using One-way ANOVA and Dunnett-t test. Differences were considered significant when P 〈 0. 05. Results Pretreatment with RXR agonist enhanced cell viability, reduced apoptosis ratio, stabilized mitochondrial membrane potential. Dot blotting experiments demonstrated that under H/R stress conditions, Bel-2 protein leveldecreased, while Bax and cleaved Caspase-9 increased. The c-RA administration prior to H/R stress prevented these effects, however, overall protective effects of activating RXR on rat cardiomyocytes against H/R induced oxidative injury were abolished when pretreated with RXR pan-antagonist HX531. Conclusions Activating RXR has the protective effects against H/R injury in rat cardiomyocytes H9c2 through attenuation of mitochondria apoptosis signaling pathway.

关 键 词：维甲类X受体 心肌细胞 凋亡 线粒体 缺氧 复氧 

分 类 号：R965[医药卫生—药理学]