机械牵张对缺血缺氧心肌细胞肌球蛋白重链mRNA表达的影响  

Influence of mechanical stretch on the expression of myosin heavy chain mRNA in cardiomyocyte subjected to ischemia and hypoxia

作　　者：李晓东[1] 黄跃生[1] 张家平[1] 

机构地区：[1]第三军医大学西南医院全军烧伤研究所,创伤烧伤复合伤国家重点实验室,重庆400038

出　　处：《中华烧伤杂志》2004年第3期138-140,共3页Chinese Journal of Burns

基　　金：国家杰出青年科学基金资助项目 (3 0 12 5 0 40 ) ;国家重点基础研究发展规划资助项目 (G1990 5 42 0 2 );创伤烧伤复合伤国家重点实验室开放课题基金资助项目 (2 0 0 3 0 4)

摘　　要：目的　探讨机械牵张对缺血缺氧心肌细胞肌球蛋白重链 (MHC)mRNA表达的影响。方法　建立离体培养的SD乳鼠心肌细胞机械牵张模型 ,并施加无糖缺氧刺激因素 ,模拟烧伤后缺血缺氧损害。实验分 10 %牵张组、缺血缺氧培养组、10 %牵张 +缺血缺氧培养组 ,每组每时相点 3皿细胞。各组分别在刺激前和刺激后 1、3、6、12h时相点进行观察。采用二步法逆转录聚合酶链反应检测心肌细胞MHCmRNA表达的变化 ,并用凝胶软件进行分析。　结果　与刺激前比较 ,10 %牵张组α、β型MHCmRNA表达均增加 ,但以 β型增加为主 (P <0.0 1)。缺血缺氧培养组α MHCmRNA向 β MHCmRNA转化加速 ,且缺氧 12h后心肌细胞α MHCmRNA下调明显 (P <0.0 5);β MHCmRNA表达先升后降 ,6h表达最强 (P <0.0 5 )。10 %牵张 +缺血缺氧培养组α MHCmRNA向 β MHC mRNA转化明显 ,随机械刺激时间的延长转化加剧 ;12h后α、β型MHCmRNA表达均下调 (P <0.0 5)。　结论　机械牵张进一步加剧缺血缺氧对MHCmRNA表达的下调 ,可能是严重烧伤后早期心肌功能降低的原因之一。Objective To investigate the influence of mechanical stretch on the expression of myosin heavy chain (MHC) mRNA in cardiomyocyte subjected to ischemia and hypoxia. Methods Mechanical stretch model of in vitro cultured cardiomyocyte was established for the study. The cells were processed by non-sugar hypoxic stimuli to simulate postburn ischemic and/or hypoxic injuries. The cells were then divided into normal control (N), 10% stretch (S), ischemic and hypoxic culture (IHC), 10% stretch with ischemia and hypoxia (SIHC) groups. The changes in MHC mRNA expression were observed at 1,3,6 and 12 post treatment hours (PTHs) by RT-PCR and were statistically analyzed with gel image analysis software. Results The expression of both α and β MHC mRNA increased in 10% stretch group, especially of β MHC mRNA ( P < 0.01). The transformation of α MHC mRNA to β MHC mRNA was accelerated in IHC group, and α MHC mRNA expression was decreased at 12 PTH. The expression of β MHC mRNA was increased after ischemia and hypoxia, peaked at 6 PTH, and decreased thereafter ( P <0.05). The transformation of α MHC mRNA to β MHC mRNA was more obvious in SIHC group, and which was intensified along with the elapse of stimulation time. The expression of both α and β MHC mRNA were down-regulated at 12 PTH ( P < 0.05 ). Conclusion Down regulation of MHC mRNA expression by ischemia and hypoxia could be aggravated by mechanical stretch, indicating that mechanical stretch might be a possible cause for cardiac dysfunction.

关 键 词：机械牵张 缺血缺氧心肌细胞肌球蛋白重链 MRNA 表达 心肌缺血 

分 类 号：R644[医药卫生—外科学]