Replication of animal models of myocardial ischemia and myocardial infarction

Methods for replicating myocardial ischemia and myocardial infarction in animals include ligation of coronary arteries, and ligation of left-handed coronary arteries, but most of them are ligated to the left anterior descending coronary artery. In view of the high mortality of ligated coronary arteries, multiple ligation is also used. The method is to simultaneously ligature several branches of the coronary artery to form an infarct area. Experience has shown that the ligated coronary arteries determine the area of ​​myocardial infarction because of the distribution of the myocardium and whether there are other coronary arteries in the area. The ligation method is a very early and still common method. In addition, oily, cecroporous or mercury is used for diffuse coronary microembolization or selective coronary infarction. The former is mostly used in the early years. In recent years, plastic particle surgery has been invented, and the number of infarcts in different ranges is determined by the number of the particles and the size of the sphere. In the latter case, a coronary artery is targeted, and a granular or small ball foreign body is input through a catheter. This method requires skill and strict conditions. There are also methods such as energization to cause embolization in the coronary arteries. However, these methods are not used much because of various conditions.

In recent years, in order to establish a gradual development of myocardial infarction model, a water-swellable cellulose ring (Ameriod) is widely used. The cellulose ring is placed on the coronary artery that is expected to be occluded, and the outer ring is made of metal. The ring (such as stainless steel) is fixed and the coronary artery can be gradually occluded two weeks or more after surgery. This model is easier to manufacture and has a higher animal survival rate. But the use of such methods still lacks the pathological basis of human atherosclerosis. Recently, it has been reported that domestic pigs can be fed a high-fat diet to form atherosclerosis of the coronary arteries, causing myocardial ischemia, and the atherosclerotic plaque can be resolved by changing diet or treatment. It seems that this is a goal worthy of exploration.

The animals selected for replication of the myocardial infarction model are mostly mammals, the most common of which are dogs. Others include rabbits, calves, pigs, guinea pigs, and rats. The dog is moderately sized and temperate and easy to train. However, the coronary vascular structure of dogs is quite different from that of humans, especially in the canine coronary artery variability, the collateral anastomosis is abundant, and the ventricular septal artery is particularly developed, which often makes the researchers distressed. In recent years, the structure of the coronal circulatory system is similar to that of humans. Therefore, experimental research on the use of domestic pigs or piglets for myocardial infarction has been advocated, but no report has been reported in China. Other small arteries, rabbits, mice, etc., are too small, and the materials are limited, so there are not many used except for specific conditions. Primate cockroaches and monkeys of course have incomparable superiority to other animals, but their materials are rare and difficult to use. Domestic replication methods for myocardial ischemia and myocardial infarction models:

1 . Electrical stimulation

It is a relatively new method established in recent years to cause experimental myocardial ischemia in animals. The experiment generally uses adult male rabbits. After anesthesia, insert two stainless steel needles coated with insulating paint with a directional instrument to stimulate the right hypothalamus with weak and strong stimulation (weak stimulation is 0.8-1.6 mA, strong stimulation is 4-8 mA). The medial dorsal nucleus is stimulated for 5 minutes each time, with an interval of 1 to 3 minutes.

2 . Drug law

It is also a method adopted in recent years. The most commonly used modeling drug is 4% isoproterenol, and the rats are injected subcutaneously with 50 mg/kg body weight; or the drug is added to 500 ml of saline and instilled from the rabbit ear vein at a constant rate (4 hours). Dosing 10, 20, 30 mg, or directly injecting the drug into the abdominal cavity can be molded. Anesthetized dogs can also be used to intravenously administer ergot xinxin 0.2 mg/kg body weight, resulting in coronary artery spasm.

3 . Coronary artery occlusion