缺血/再灌注心肌肌浆网肌钙调控蛋白mRNA表达的变化

THE CHANGES IN THE mRNA LEVELS OF CALCIUM REGULATORY PROTEINS IN ISCHEMIA/REPERFUSION RAT VENTRICLES

目的:研究缺血/再灌注损伤心肌肌浆网四种钙调控蛋白mRNA表达的变化。方法:将SD大鼠分为正常对照组和缺血/再灌注损伤组,采用Langendorff离体灌流技术,全心停灌15 min后行45 min复灌制备缺血/再灌注模型,记录心脏收缩功能各项参数(左室发展压、+dp/dt-max-、dp/dt-max),进行心律失常评分,同时对两组心肌标本进行半定量RT-PCR检测,测定SERCA、PLBI、P3R2和RyR2四种蛋白质的mRNA表达水平的变化。结果:与正常对照组比较,各时间点缺血再灌注心脏左室发展压、+dp/dt-max-、dp/dt-max均显著下降,再灌注阶段的心律失常评分明显增高,同时发现心脏SERCA,IP3R2,RyR2mRNA表达降低,然而PLB mRNA表达未出现变化。结论:缺血再灌注损伤造成心脏功能减退,心律失常增多,并可诱导心室肌钙调控蛋白SERCAI、P3R2、RyR2mRNA表达下调。

Aim： To investigate the changes in the expression of four kinds of calcium regulatory proteins mRNA on the isolated ischemia/ reperfusion（IR） hearts. Methods： The rat hearts were divided into two groups： control group and IR group which received 45 min exposure to Krebs- Henseleit solution after 15 min zero-flow global ischemia. The indexes of left ventricular function, such as LVDP, ＋ dp/dtmax, -dp/dtmax, and an arrhythmia scoring system were compared between the two groups. The messenger ribonucleic acid （mRNA） amount of sarcoplasmic reticulum（SR） Ca^2＋ ATPase （SERCA）, phospholamban（PLB）, inositol 1,4,5- trisphosphate receptor2 （ IP3R2 ） and ryanodine receptor2 （ RyR2 ） was measured by reverse transcription-polymerase chain reaction （RT-PCR） and norma lized to the mRNA levels of β-actin. Results： In the IR group, LVDP, ＋ dp/dtmax and -dp/dtmin of the isolated hearts were depressed and the high rate of arrhythmias occurred during reperfusion. The levels of SERCA, IP3R2 ,RyR2 mRNA were lower in the IR isola ted hearts group than those in the control group, while there was no difference in the level of phospholamban. Conclusion： These data suggest that myocardial ischemia/reperfusion can induce the depression of cardiac performance and an increased risk of arrhythmias, concomitanting with the decrease in SERCA,IP3R2 ,RyR2 mRNA steady state levels.