心肌缺血期应用环孢素A对大鼠心肌功能的影响

Effect on rats′ myocardial function induced by Cyclosporine A during myocardial ischemic period

目的:通过大鼠心肌缺血期应用线粒体通透性转换孔(mPTP)抑制剂环孢素A(CsA),观察其心肌保护能力,探讨该方式诱导大鼠心肌保护的可行性。方法:42只健康雄性Wistar大鼠经胸骨下段切口暴露心脏,打活结的方式结扎冠状动脉左前降支(LAD),建立在体心肌缺血/再灌注损伤模型。①Sham组(n=8):将缝线穿过LAD下方,但不结扎。②缺血/再灌注组(IR组,n=12):心脏LAD实施30 min缺血/180 min再灌注处理;③心肌缺血期短暂肢体缺血处理组(RP组,n=12):心脏LAD实施30 min缺血/180 min再灌注处理;在实施心肌缺血期间对双下肢实施3次5 min缺血/5 min再灌注;④环孢素A组(CS组,n=10):心脏LAD实施30 min缺血/180 min再灌注处理;心肌缺血期间经心脏测压管注射CsA 10 mg/kg。计算缺血期心律失常(ischemia arrhythmia,IA)及再灌注性心律失常(reperfusion ar-rhythmia,RA)评分;比较左心室发展压(LVDP)、左心室压上升/下降最大速率(±dp/dtmax);HE染色观察心肌组织形态,TTC染色法测定心肌梗死面积。结果:CS组与RP组再灌注早期RA评分均低于IR组(P=0.045、0.023),但CS组与RP组比较差异无统计学意义(P>0.05)。CS组再灌注30、60、120、180 min时,LVSPmax(P=0.033、0.001、0、0)和再灌注120、180 min时±dp/dtmax(P=0.046/0.020和P=0.015/0.025)显著低于IR组。CS组再灌注60、120、180 min时,LVSPmax(P=0.012、0、0)、再灌注60 min时-dp/dtmax(P=0.026)及再灌注180 min时±dp/dtmax显著低于RP组(P=0.014/0.012)。HE染色发现CS组存在严重心肌组织水肿。CS组心梗范围介于RP、IR组之间,RP组心梗范围显著小于IR组(P=0.001)、CS组(P=0.043),CS组显著小于IR组(P=0.026)。结论:心肌缺血期心腔注射CsA通过抑制mPTP的开放,减少RA,其效果与RP相当,但同时存在对心肌的严重副损伤。针对CsA和心肌mPTP的研究可能对心肌保护产生积极影响。

Objective： To study the capability of myocardial protection of Cyclosporin A,the inhibitor of mitochondrial permeability transition pore（mPTP） applied during myocardial ischemic period of rats,and to discuss the feasibility of that method.Methods： Healthy male Wistar rats were administered.The heart was exposed through lower sternal incision and the left anterior descending coronary artery was ligated by slipknot to establish the ischemia/reperfusion model.42 rats were assigned randomly into four groups.①Sham group（n=8）： rats were threaded a silk suture under the left coronary artery anterior descending（LAD） and laid up throughout the experiment.②IR group（ischemial reperfusion group）（n=12）： rats were subjected to 30 min LAD occlusion followed by 180 min reperfusion.③RP group（transient limb ischemic conditioning during myocardial ischemia period,remote perconditioning group）（n=12）： rats were subjected to three episodes of 5 min double hind limbs occlusion followed by 5 min reperfusion during 30 min myocardial ischemia period which followed by 180 min reperfusion.④CS group（Cyclosporine A group）（n=10）： rats were subjected to 30 min LAD occlusion followed by 180 min reperfusion while CsA was injected into the left ventricle from the catheter dosed with 10 mg/kg.The scores of ischemia arrhythmia and reperfusion arrhythmia,the left ventricular developing pressure,the maximal change index of LV（±dp/dtmax） were calculated.The myocardial morphology was observed by HE staining.Myocardial infarct size was measured by TTC staining technique.Results： RA scores of CS group and RP group were lower significantly than IR group（P=0.045,0.023）,while no significant difference was found compared to RP group.Compared to IR group,LVSPmax was lower significantly at reperfusion time of 30,60,120 and 180 min（P=0.033,0.001,0,0）;±dp/dtmax was lower significantly at reperfusion time of 120 and 180 min（P=0.046/0.020 and P=0.015/0.025）.Compared to RP group,LVSPmax was lower at reperfusion time of 60,120 and 180 min（P=0.012,0,0）;-dp/dtmax at reperfusion time of 60 min and ±dp/dtmax at reperfusion time of 180 min were lower significantly（P=0.026,and P=0.014/0.012）.Severe myocardial edema was found in CS group.The infarct size of CS group fell in between RP group and IR group.The infarct size of RP group was significantly smaller than that of IR group（P=0.001） and CS group（P=0.043） while the difference of infarct size between CS and IR group was statistically significant（P=0.026）.Conclusion： CsA which injected into heart chamber during myocardial ischemic period can inhibit open of mPTP and reduce RA.The effect is similar to the method of remote conditioning by transient limb ischemia,but it can induce severe side injury.Research aiming at CsA and myocardial mPTP may generate positive impact on myocardial protection.