液氮冷冻大鼠左冠状动脉前降支中上1／3所支配区域建立心肌梗死模型

Establishment of Myocardial Infarction Models by Freezing Regional Dominance of the Middle-upper 1/3 Segment of the LAD in Rats with Liquid Nitrogen

目的探讨大鼠左冠状动脉前降支中上1/3所支配的区域液氮冷冻处理后对心肌形态学及心功能的影响,以建立适合移植干细胞再生修复心肌梗死研究的一种新的大鼠心肌梗死模型制作方法。方法80只雄性SD大鼠,随机分为3组即:冷冻组、结扎组、对照组。大鼠麻醉后,行气管插管连通动物呼吸机,打开胸廓暴露心脏,用特制的直径为0.6 cm冷冻头置入液氮中冷冻降温后迅速冷冻大鼠左冠状动脉前降支中上1/3所支配的区域,或结扎左冠状动脉前降支中上1/3处。分别于处理后1 d、3 d7、d1、4 d、28 d观察心脏病理组织学变化,并于处理28 d后检测心功能的变化。结果在液氮冷冻大鼠心脏后,大鼠心肌组织出现凝固性坏死,继而有肉芽组织长人梗死灶内,最后形成疤痕。用液氮冷冻法可成功复制心肌梗死大鼠动物模型。与冠状动脉结扎法相比较,操作简单,手术时间短,死亡率低,心肌梗死面积变异小。结论液氮冷冻法作为一种复制心肌梗死模型的方法,有其自身的优势,可用于心肌梗死发生机制和干细胞治疗等方面的研究。

Objective To explore the effect of freezing regional dominance of the middle-upper 1/3 segment of left anterior distending artery （LAD） in Rats on Myocardial（ morphology and cardiac function after being frozen instantly by liquid nitrogen, which provides a considerably reliable model for the study of repair or rebuild rat myocardial infarction by stem cells transplantation. Methods 80 male SD rats were randomly divided into three groups： refrigeration group, hgation group, control group. Rats were anesthetized and intubated and ventilated via a tracheal cannula using ventilator, then left thoracoto was performed. Myocardial infarction was induced by ligation of the middle-upper 1/3 segment of the LAD or by freezing regional dominance instantly by liquid nitrogen of the middle-upper 1/3 segment of the LAD with a magnitude of the diameter of 0.6 cm frozen needle, lday,3day, lweek,2weeks or 4weeks after different treatment, Pathological morphology were be observed and at 4weeks cardiac functions were detected and analyzed. Results After rat heart was frozen with liquid nitrogen, myocardial tissue occurred coagulation necrosis, and then there were granulation tissue in infarction areas. Finally scar was formed. Compared with ligating coronary artery, applicating with frozen method has simpler operation, shorter surgery time, low mortality and smaller myocardial infarction area variation Conclusion Myocardial infarction model through freezing with liquid nitrogen has its own advantages, and can be used to study the mechanism of myocardial infarction and stem cell therapy repairing injured heart.