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目的建立稳定、高质量心肌梗死动物模型对心脏病实验研究十分重要,模型个体间的梗死面积和心功能差异过大可能对研究结果构成混杂和干扰。由于猪对角支变异较大,以对角支为坐标结扎前降支(LAD)建立的心肌梗死模型心功能变异较大,本研究探讨猪LAD结扎百分位点和心肌梗死体积、左室射血分数(LVEF)的关系,以期指导研究者根据急性心肌梗死模型的心功能要求选择合适的LAD结扎百分位点。方法小型猪开胸结扎心脏LAD中远段约30％-75％的不同百分位点,分别于术前、术后1 h心脏超声检查LVEF,术后3 d进行常规冠状动脉造影,4周处死测量LAD结扎位点和梗死体积,最后用简单直线回归模型分析LAD结扎百分位点和心肌梗死体积、LVEF回归方程和相关系数．结果①47头猪LAD结扎后因心室颤动死亡28头,39头存活动物冠状动脉造影均显示LAD中远段结扎部位处完全闭塞,表明手术成功。②39头存活动物术前LVEF为(67．67±5．88)％,术后1 h为(41．47±8．82)％;大体病理学测量LAD全长平均为(8．78±0．25)cm,有3-6个左室分支,分支的大小、位置和数量均不固定,D1和D2分别位于(18±5)％和(34±8)％百分位点;LAD远段绕过心尖约0．3-1．5 cm。LAD结扎百分位点为22．5％-72．9％,平均为(44．51±13．94)％。左室梗死区重量占左室重量的(18．13±8．21)％。③LAD结扎百分位点与术后1 h LVEF、术后1 h LNEF下降值、梗死心肌体积均明显相关(r=0．87、0．78和0．90,P值均<0．01),其回归方程分别为:术后LNEF(％)= 65．88-0．55×结扎百分位点,术后LNEF下降值(％)=0．15-0．59×结扎百分位点,心肌梗死体积(％)=0．53×结扎百分位点-5．43。据此推算,于70％、60％、50％、40％和30％百分位点结扎猪心脏LAD,心肌梗死动物模型的心肌梗死体积分别为32％、26％、21％、16％和10％,相应的术后LNEF分别为28％、33％、38％、44％和49％。结论猪LAD结扎百分位点与术后左室功能、梗死心肌体积均存在显著相关性,可根据实验目的和对心功能的要求选择合适的结扎百分位点。
Objective To establish an animal model of stable and high quality myocardial infarction is very important for the experimental study of heart disease. Too much difference in infarct size and cardiac function between model individuals may cause confusion and disturbance to the research results. Due to the large diagonal branch variation in pigs, cardiac function variations in myocardial infarction models established by diagonal branch ligament anterior descending coronary artery occlusion (LAD) are quite large. This study investigated the relationship between pig LAD ligation percentage and myocardial infarction volume, left ventricular Ejection fraction (LVEF) relationship, with a view to guide the researchers according to the cardiac function of acute myocardial infarction model to select the appropriate LAD ligation percentile. Methods Mini-pigs underwent open heart thoracotomy for about 30% -75% of different percentiles in the mid-LAD of the heart. LVEF was performed at 1 h before and 1 h after operation. Conventional coronary angiography was performed 3 days after operation and was sacrificed at 4 weeks LAD ligation sites and infarct volume were measured. Finally, simple linear regression model was used to analyze LAD ligation percentage and myocardial infarction volume, LVEF regression equation and correlation coefficient. Results ①47 pigs died of ventricular fibrillation after LAD ligation, and 39 of them survived coronary angiography showed complete occlusion of the LAD mid-distal ligation site, indicating that the operation was successful. (2) The preoperative LVEF of 39 surviving animals was (67.67 ± 5.88)%, and (41.47 ± 8.82)% 1 h after the operation; the average length of LAD in the gross pathology was (8.78 ± 0) .25) cm with 3-6 left ventricular branches, the size, location and number of branches were not fixed, D1 and D2 were located at (18 ± 5)% and (34 ± 8)% percentiles; LAD Section around the apex of about 0.3-1.5 cm. LAD ligation percentage point was 22.5% -72.9%, with an average of (44.51 ± 13.94)%. The weight of left ventricular infarction area accounted for (18.13 ± 8.21)% of left ventricular weight. (3) The LAD ligation percentile was significantly correlated with the LVEF 1 h after operation, the LNEF depression at 1 h, and the myocardial infarct size (r = 0.87, 0.78 and 0.90, P <0.01) , The regression equation was: postoperative LNEF (%) = 65.88-0.55 × ligation percentile, postoperative LNEF decreased value (%) = 0.15-0.59 × ligation percentage points , Myocardial infarction volume (%) = 0.53 × ligation percentage point -5.43. Based on the above data, myocardial infarction volumes of myocardial infarction models were 32%, 26%, 21% and 16% at the LAD of 70%, 60%, 50%, 40% and 30% The corresponding postoperative LNEF were 28%, 33%, 38%, 44% and 49%, respectively. Conclusion There is a significant correlation between LAD ligation percentage and postoperative left ventricular function and myocardial infarct size. The suitable ligation percentile can be selected according to the purpose of experiment and the requirement of cardiac function.