猪急性心肌梗死模型的建立

目的：探讨应用经皮腔内冠状动脉成形术（PTCA）球囊堵闭猪冠状动脉建立急性心肌梗死动物模型的实验方法。方法：选用苏中幼猪12只，麻醉后经股动脉置入PTCA球囊至冠状动脉左回旋支分支，堵闭血流90min，行心电图、血流动力学、心脏二维超声、TTC染色及光镜、电镜检查以判断急性心肌梗死模型是否成功建立。结果：12只猪均完成冠状动脉左回旋支分支的封堵，部分实验动物显示心电图呈典型急性心肌梗死动态图形变化，球囊堵塞1h后超声检查出现心室局部运动异常；堵塞90min再灌注30min后处死猪，取出心肌作TTC染色及光镜、电镜检测，证明成功建立猪急性心肌梗死模型。结论：应用门CA球囊封堵冠状动脉可成功建立猪急性心肌梗死模型，方法简便易行，具有创伤小、死亡率低等优点。     

中国实验用小型猪急性心肌梗死再灌注模型的建立

目的：探讨介入球囊堵闭冠状动脉的方法建立中国实验用小型猪急性心肌梗死（AMI）再灌注模型的可行性。方法：中国实验用小型猪11只,在麻醉状态下通过介入球囊堵闭前降支远端90min,然后撤出球囊形成AMI再灌注模型。通过心电图（ECG）、磁共振成像（MRI）进行活体评价,并与氯化三苯四唑（TTC）染色对照分析。结果：8只猪模型制作成功,其余3只死于室颤,成功率72．73％。ECG显示sT段呈弓背向上抬高型心肌缺血再灌注损伤图形。MRI显示梗死心肌均位于心尖部、左心室前壁和室间隔前部,其体积百分比为（21．6±6．1）％。TTC染色所示梗死心肌部位与MRI一致,体积百分比为（21．1±6．2）％。两者问的差别无统计学意义（P〉0．05）。结论：介入球囊堵闭冠状动脉的方法可成功建立AMI再灌注模型,为相关研究提供实验动物模型基础。     

小型猪心肌梗死模型的制作和判定

制作小型猪心肌梗死和缺血模型，并建立活体判断模型建成与否的观察指标。方法：12只16～22kg小型猪分为2组，每组6只，第一组结扎回旋支制作心肌梗死模型，第二组用ameroid环制作心肌缺血模型。用心肌^99mTc-MIBI血流灌注显像在活体确定其梗死区或缺血区，并在处死动物后用TTC法验证其梗死或缺血灶。结果：成功建立小型猪心肌梗死和缺血的动物模型，^99mTc—MIBI心肌血流灌注显像可在活体上显示小型猪模型心肌梗死灶的放射性缺损区和缺血灶灌注缺损区的放射性再充填。离体心肌TTC染色可显示相应的梗死或缺血灶。结论：结扎回旋支和ameroid环缩窄回旋支是制备小型猪心肌梗死和缺血模型的较好方法，可用^99mTc-MIBI心肌灌注显像在活体上确定模型成与否。     

经皮球囊扩张封堵冠状动脉前降支制备巴马香猪急性心肌梗死模型

目的探讨经皮球囊扩张封堵冠状动脉前降支（LAD）制备巴马香猪急性心肌梗死（AMI）模型的方法及可行性。方法经右股动脉置人冠状动脉球囊导管至左前降支;预适应3～4次,每次球囊充盈30s,间隔5～10min;以3～5atm扩张球囊封闭LAD远端血流,40min后撤除球囊。结果8头巴马香猪中有6头存活,造模成功率为75％。模型梗死面积变异系数为11．7％（33．2±3．9）。封堵后心电图呈动态变化,心肌酶学指标（CK、CK—MB、cTnI、Myo、LDH）较术前明显升高,心脏彩超左心室舒张末内径、左心室舒张末容积及左心室收缩末容积均增大,LVEF均下降,部分实验猪出现心室壁瘤,TIC染色、HE染色证实心肌梗死模型建立成功。结论经皮球囊扩张封堵法制备巴马香猪急性心肌梗死模型成功率高,保持了梗死区冠脉可重复进行造影,为干细胞植入梗死区心肌治疗AMI提供了较好的动物模型。     

实验用猪急性心肌梗死模型的制备

目的：探讨经皮冠状动脉内球囊封堵法建立实验用猪急性心肌梗死模型的可行性及有效性。方法：健康家猪14只，3～5月龄，体重25～40kg（35．5±6．6）。麻醉后穿刺股动脉，行冠脉造影后沿血管送冠脉球囊至冠状动脉左前降支（LAD）近中段，即第二间隔支动脉分出处。动物随机分为2组，A组动物（n=7）行缺血预适应处理，依次扩张球囊阻断前向血流1、2、5min，每次间隔60s，然后扩张60min，扩张压力为2atm。B组动物（n=7）不行缺血预适应处理，直接扩张球囊阻断前向血流扩张60min，扩张压力为2atm。建立模型前、建立模型后1h行心脏MRI及心电图检查，术中行心电监护。结果：成功建立猪心肌梗死模型12例，B组动物死亡2例。术中共有12例动物发生室颤，其中10例经过电复律等抢救成功转复。12例建模成功动物术中心电图出现急性心肌梗死典型图形变化，术后心脏MRI检查出现间隔及前壁首过灌注缺损，延迟强化。结论：经皮腔内冠脉球囊封堵冠状动脉可以建立实验用猪急性心肌梗死模型，缺血预处理可提高建模成功率。     

经皮冠脉内球囊封堵建立猪心梗模型

目的探讨经皮冠状动脉内球囊封堵建立猪急性心肌梗死模型的方法。方法健康猪11只，4-5月龄，体重25～40kg。其中7例球囊置于第三间隔支动脉分出处，4例置于第二间隔支动脉分出处。试验前每只动物均进行缺血预适应，阻断前向血流1min、2min、5min，每次间隔60s，然后持续阻断前向血流60min。球囊扩张压力为2atm。观察心电图、心脏二维超声及冠状动脉和左心室造影。结果成功建立猪心肌梗死模型9例，2只因术中顽固性室颤死亡，死亡者一例为左前降支中段阻断，心电图及活检证实为广泛前壁心梗。共有7例发生室颤，其余5例均抢救成功。心电图显示急性心肌梗死典型图形变化，术后1h超声检查出现梗塞部位局部运动异常，心脏MRI检查出现梗塞部位首过灌注缺损，延迟强化。结论经皮腔内球囊封堵冠状动脉可成功建立猪急性心肌梗死模型，具有创伤小、动物生存时间长并易于术后饲养等优点。     

缺血后处理抗猪心肌梗死致心律失常的作用研究

目的探讨球囊封堵冠脉建立猪心肌梗死动物模型中心律失常的发生和防治方法．方法实验猪11只,随机分为2组．实验组（n=6）：在X线的监控下,经右股动脉置入冠状动脉球囊导管至左前降支,球囊扩张阻断血流60min,予8次30s／30s短暂缺血再灌注即缺血后处理;对照组（n=5）：不行缺血后处理,直接撤除球囊．行持续监测心电及血压,并行心电图检查．结果冠脉造影、心电图,心肌酶学及病理学检查证实9只猪成功建立心肌梗死模型．实验组3只发生再灌注心律失常（50％）,无1只死亡,建模成功率为100％．对照组5只发生再灌注心律失常（100％）,死亡2只（40％）,建模成功率为60％．2组比较差异有统计学意义（P〈0．05）．结论缺血后处理可有效地减少心梗模型中心律失常的发生,提高建模成功率．     

应用MRI活体示踪干细胞心肌移植可行性的实验研究

目的：探讨应用MRI活体示踪干细胞心肌移植的可行性.方法：选择8只雌性家猪,体重35～45 kg,经导管应用球囊封堵前降支动脉建立心肌梗死模型后,将存活的7只随机分为Feridex标记的干细胞移植组（n=4）和Feridex未标记的干细胞移植组（n=3）.建立模型2周后开胸,在梗死区中央及梗死边缘区共5个点注射骨髓间充质干细胞（BMSC）（1.25～7.54×10^6）.于移植前及移植后1 h、1周、2周分别行心脏MRI 检查,比较移植前后MRI心脏影像学变化.移植后2周,取心脏组织行HE染色和普鲁士蓝染色.结果：移植后1 h,Feridex标记的干细胞移植组中4只动物（100%）间充质干细胞移植区在MRI上呈明显的低信号改变,术后1周示心脏低信号改变达100%（4只动物）,术后2周示2只动物（50%）细胞移植区有低信号改变.病理检查示梗死区内大量炎性细胞浸润,Feridex标记的干细胞移植组心脏注射点处的组织普鲁士蓝染色阳性.结论：Feridex标记的干细胞在MRI上呈低信号改变,应用MRI活体示踪BMSC是可行的.     

猪缺血再灌注损伤与心肌细胞凋亡的实验研究

目的探讨猪心肌梗死不同区域细胞凋亡的分布。方法滇南小耳猪10只,随机分为两组,每组5只。(1)假手术组(S组),在X线的监控下,经右股动脉置入冠状动脉球囊导管至左前降支,不行冠脉封堵心肌缺血;(2)缺血再灌注组(I/R组),冠脉球囊扩张阻断冠脉血流60min致心肌缺血,撤除球囊恢复冠脉灌注。再灌注72h,行猪心肌末端标记法(TUNEL法)检测凋亡细胞及免疫组化法检测Bcl-2和Bax的蛋白表达。结果再灌注后72h,S组未发生心肌梗死及心肌细胞凋亡,I/R组在心肌梗死区、边缘区、非梗死区的心肌组织均存在细胞凋亡现象,梗死区和边缘区的心肌细胞凋亡指数(AI)明显高于非梗死区,且相应区域的Bax蛋白表达及Bax/Bcl-2比值均较非梗死区增加(P<0.05)。结论猪心肌缺血再灌注损伤后心肌梗死区、梗死边缘区、非梗死区均存在心肌细胞凋亡现象,细胞凋亡主要分布在梗死区和边缘区。     

闭胸式冠状动脉插管法建立犬急性心肌缺血模型

目的 探讨应用闭胸式冠状动脉插管法建立犬急性心肌缺血模型的方法及可行性.方法 杂种犬11只,麻醉后经右侧颈总动脉置入冠状动脉成形术球囊至冠状动脉前降支远端,堵闭120 min,建立急性心肌缺血后再灌注模型;注入手术逢线或细颗粒状明胶海绵,建立急性心肌梗死模型.梗死及正常区域取标本进行TTC大体染色及HE染色观察.结果 3只犬成功建立了急性心肌缺血后再灌注模型,5只犬成功建立了急性心肌梗死模型并存活3 d,TTC染色发现梗死范围与左前降支供血范围一致,HE染色证实心肌梗死区域.1只因麻醉过量死亡;1只误栓入右冠状动脉;1只误栓入左冠状动脉主干,栓塞后4 min诱发心室颤动而死亡.结论 闭胸式冠状动脉插管法建立犬急性心肌梗死模型具有创伤小、动物生存时间长,技术要求相对较低、可重复进行冠状动脉造影和电生理检查等优点,此种建立急性心肌梗死模型的方法具有可行性.     

Establishment and evaluation of a swine model of acute myocardial infarction and reperfusion–ventricular fibrillation–cardiac arrest using the interventional technique

BackgroundVentricular fibrillation is the main cause of sudden cardiac death among patients with acute myocardial infarction (AMI). Substantial benefits could be obtained by both researchers and practitioners if an AMI reperfusion-ventricular fibrillation-cardiac arrest model were established.MethodsTwenty swine were anesthetized and underwent occlusion of the left anterior descending branch for 90 minutes prior to blood reperfusion. Throughout this process, continuous 12-lead electrocardiography (ECG) was used to monitor heart rate, rhythm, and electrocardiogram alteration. Thereafter, AMI was confirmed by ECG and left ventricular angiography. Heart tissue was collected for pathological analysis, and for evaluation of the establishment of a model of AMI reperfusion.ResultsSeven swine died during the model establishment, and the 13 surviving swine were proven to have myocardial infarction; nine of those survivors had ventricular fibrillation–cardiac arrest after reperfusion based on the electrocardiograph and pathological examination.ConclusionBlocking the left anterior descending branch by inflation of an over-the-wire coronary balloon catheter in swine can result in successful establishment of a swine model of AMI and reperfusion–ventricular fibrillation–cardiac arrest, with good reproducibility and a high survival rate.     

缺血后处理对猪急性心肌梗死后的抗氧化作用

目的探讨缺血后处理对猪急性心肌梗死后的抗氧化作用.方法滇南小耳猪15只,随机数字表法分为3组,假手术组(S组,n=5),缺血再灌注组(IR组,n=5),缺血后处理组(IPC组,n=5).用球囊封堵冠脉建立猪闭胸式心肌梗死模型,术中监测心电及血压,测定缺血前、再灌注2 h及24 h血清超氧化物岐化酶(SOD)活力及丙二醛(MDA)含量,再灌注72 h采用2,3,5氯化三苯基氯四氮唑(TTC)染色确定心肌梗死面积.结果 (1)与假手术组相比,缺血再灌注组再灌注2 h,24 h MDA含量明显增加,SOD活力明显降低(P<0.05);与缺血再灌注组相比,缺血后处理组再灌注2 h,24 h MDA含量明显下降,SOD活力明显增加(P<0.05);(2)假手术组未发生心肌梗死,缺血再灌注组及缺血后处理组心肌梗塞的面积分别是(23.26±3.13)%,(10.89±2.02)%,缺血后处理组心肌梗塞面积较缺血再灌注组明显降低(P<0.05).结论缺血后处理对猪的心肌保护作用可能与其减少脂质过氧化产物MDA的含量,提高抗氧化物质SOD活性的抗氧化作用有关.     

Increased incidence of silent ischemia after acute myocardial infarction.

OBJECTIVE--To determine the incidence of angina pectoris during induced myocardial ischemia in patients who have had thrombolytic therapy for acute myocardial infarction in comparison with patients with angina pectoris. DESIGN--During percutaneous transluminal coronary angioplasty, both study groups had coronary artery occlusion by the balloon dilatation catheter for 5 minutes. SETTING--A tertiary, cardiology referral center. PATIENTS--Twenty-five patients with angina pectoris who were undergoing angioplasty were compared with 30 patients having angioplasty 2 days after thrombolytic therapy for acute myocardial infarction. OUTCOMES--Development of angina pectoris during balloon occlusion of the coronary artery was the primary end point; the ischemic response and muscle viability were assessed using both surface and intracoronary electrocardiograms and pulmonary artery wedge pressure. RESULTS--During balloon occlusion 16 (64%) of 25 patients in the angina pectoris group developed angina. In contrast, nine (30%) of 30 patients in the thrombolysis group had angina pectoris during balloon occlusion of the infarct artery (P less than .01). The electrocardiographic response to ischemia and changes in pulmonary wedge pressure were similar in the two study groups. CONCLUSION--After thrombolytic therapy for myocardial infarction, silent ischemia may be the rule rather than the exception.     

骨髓间充质干细胞移植治疗小型猪急性心肌梗死的转归

 【目的】 探讨超顺磁性氧化铁(SPIO)活体动态示踪小型猪骨髓间充质干细胞(MSC)移植治疗心肌梗死的可行性。【方法】 采用密度梯度离心法获取小型猪自体骨髓MSC,用携带绿色荧光蛋白(GFP)基因的慢病毒载体转染MSC,并用SPIO体外标记MSC-GFP。采用经皮球囊封堵法制备急性心肌梗死(AMI)模型,双标记的MSC经冠脉移植入小型猪心肌梗死区域,移植后24 h、3周、8周在MRI下进行活体动态示踪。【结果】 普鲁士蓝染色显示25 µg Fe/mL SPIO与0.8 µL/mL阳离子脂质体联合对MSC的标记率达95% ~ 100%,对绿色荧光蛋白的表达无影响,标记细胞仍均具备多向分化能力冠脉移植MSC后24 h、3周、8周MRI成像均可见梗死区域的室间隔有明显区别于周边组织的低信号。离体组织学检查可见心梗边缘区有普鲁士蓝染色阳性,荧光阳性细胞存在。【结论】 SPIO标记MSC可在MRI成像下表现出理想的信号强度和示踪时间,SPIO活体动态示踪小型猪骨髓MSC移植治疗心肌梗死是可行的。     

大蒜素可预防心肌梗死猪模型再灌注无复流现象

Objective： To evaluate whether garlicin can prevent reperfusion no-reflow in a catheter-based porcine model of acute myocardial infarction （AMI）. Methods： Twenty-two male Chinese mini swines were randomized into 3 groups： sham-operation group （n=6）, control group （n=8）, and garlicin group （n=8）. The distal part of left anterior descending coronary artery （LAD） in swines of the latter two groups was completely occluded by dilated balloon for 2 h and a successful AMI model was confirmed by coronary angiography （CAG） and electrocardiograph （ECG）, which was then reperfused for 3 h. In the sham-operation group, balloon was placed in LAD without dilatation. Garlicin at a dosage of 1.88 mg/kg was injected 10 min before LAD occlusion until reperfusion for 1 h in the garlicin group. To assess serial cardiac function, hemodynamic data were examined by catheter method before AMI, 2 h after occlusion and 1, 2, and 3 h after reperfusion. Myocardial contrast echocardiography （MCE） and double staining with Evans blue and thioflavin-S were performed to evaluate myocardial no-reflow area （NRA） and risk area （RA）. Results： Left ventricular systolic pressure and left ventricular end-diastolic pressure significantly improved in the garlicin group after reperfusion compared with the control group （P〈0.05） and 2 h after AMI （P〈0.05）. MCE showed garlicin decreased reperfusion NRA after AMI compared with the control group （P〈0.05）. In double staining, NRNRA in the garlicin group was 18.78%, significantly lower than that of the control group （49.84%, P〈0.01）. Conclustions： Garlicin has a preventive effect on the porcine model of myocardial infarction reperfusion no-reflow by improving hemodynamics and decreasing NRA.     

Efficiently tracking of stem cells in vivo using different kinds of superparamagnetic iron oxide in swine with myocardial infarction

Background  Superparamagnetic iron oxide (SPIO) particles have shown much promise as a means to visualize labeled cells using molecular magnetic resonance imaging (MRI). Micrometer-sized superparamagnetic iron oxide (MPIO) particles and nanometer-sized ultrasmall superparamagnetic iron oxide (USPIO) are two kinds of SPIO widely used for monitoring stem cells migration. Here we compare the efficiency of two kinds of SPIO during the use of stem cells to treat acute myocardial infarction (AMI).

Methods  An AMI model in swine was created by 60 minutes of balloon occlusion of the left anterior descending coronary artery. Two kinds of SPIO particles were used to track after intracoronary delivered 10⁷ magnetically labeled mesenchymal stem cells (MR-MSCs). The distribution and migration of the MR-MSCs were assessed with the use of 3.0T MR scanner and then the results were confirmed by histological examination.

Results  MR-MSCs appeared as a local hypointense signal on T₂^*-weighted MRI and there was a gradual loss of the signal intensity after intracoronary transplantation. All of the hypointense signals in the USPIO-labeled group were found on T₂^*-weighted MRI, contrast to noise ratio (CNR) decreased in the MPIO-labeled group (16.07±5.85 vs. 10.96±1.34) and USPIO-labeled group (11.72±1.27 vs. 10.03±0.96) from 4 to 8 weeks after transplantation. However, the hypointense signals were not detected in MPIO-labeled group in two animals. MRI and the results were verified by histological examination.

Conclusions  We demonstrated that two kinds of SPIO particles in vitro have similar labeling efficiency and viability. USPIO is more suitable for labeling stem cells when they are transplanted via a coronary route.