【Animal Modeling】-Animal Model of Digestive System Disease Myocardial Ischemia and Myocardial Infarction Animal Model

动物造模

z-bo

2022-02-03

392

Methods to replicate myocardial ischemia and myocardial infarction models in animals include coronary artery ligation and left circumflex coronary artery ligation, but most of the left anterior descending artery ligation. Considering the high mortality rate of major coronary artery ligation, there are multiple ligations. This method is to ligate multiple branches of coronary arteries at the same time to form the infarcted area. Experience has shown that the area of myocardial infarction depends on the area of the ligated coronary artery and the presence of other coronary arteries in the area. The ligation method was established very early and is still very common today.

　　 In addition, oil, Lycoris spores or mercury can be used for diffuse coronary microembolism or selective coronary artery infarction. The former is mainly the first method used. In recent years, plastic surgery has been invented and manufactured, and the number of infarcted areas and the size of the sphere are used to determine different infarcted areas. .. The latter is aimed at specific coronary arteries and uses a catheter method to inject particles or small spherical foreign bodies, which requires skilled technology and harsh conditions. There are also some methods, such as coronary embolism caused by electrification. However, due to various conditions, these methods are rarely used. In recent years, the cellulose ring (Ameriod) swells when exposed to water, and has been widely used to model progressive myocardial infarction. The cellulose ring is covered by the coronary artery, which may be occluded on the outside of the ring and fixed with a metal ring (stainless steel, etc.). The coronary artery can be gradually closed more than 2 weeks after the operation. Have. The model is easy to manufacture and has a high animal survival rate. However, even with this method, the pathological basis of human atherosclerosis is still lacking. A recent report pointed out that pigs fed a high-fat diet can cause coronary atherosclerosis and cause myocardial ischemia. Changes in diet and treatment may cause atherosclerotic plaques to disappear. doing. This seems to be a goal worth exploring. Most of the animals chosen to replicate the MI model are mammals, and the most commonly used is dog. Others include rabbits, calves, pigs, guinea pigs and rats. The dog is of moderate size, gentle temperament, and easy to train. However, compared with humans, the structure of canine coronary arteries is very different, and there are many changes, especially in canine coronary arteries, a large number of collateral anastomoses, and especially developed ventricular septal arteries, which often trouble researchers. . .. Recently, it has been reported that the coronary circulation structure of pigs is similar to that of humans. Therefore, some people advocate using domestic pigs or piglets for experimental research on myocardial infarction, but this is not available in China. .. Other small arteries, rabbits, mice, etc. are too small to obtain materials and are not used frequently unless under certain conditions. Although they have an undeniable advantage over other animals, let alone primates, baboons and monkeys, they have very few materials and are generally not easy to use. The replication method of myocardial ischemia and myocardial infarction in China:

　　 1. Electrical stimulation is a relatively new method recently established to induce experimental myocardial ischemia in animals. Adult male rabbits are usually used in experiments. After anesthesia, use a directional device to insert two stainless steel needles coated with insulating paint to alternately stimulate the right hypothalamus with weak and strong stimulation (weak stimulation is 0.8 to 1.6 mA, strong stimulation is 4). ? 8mA). Stimulate the dorsal medial nucleus for 5 minutes at intervals of 1 to 3 minutes.

　　2. Drug methods have also been adopted in recent years. The most commonly used fixative is 4% isoproterenol, injected subcutaneously into rats at a constant rate (4 hours), with a dose of 50 mg/kg body weight or 500 ml of normal saline, injected into the rabbit ear vein. ) Add to. It can be formed by administering 10, 20, 30 mg or directly injecting the drug into the abdominal cavity. Intravenous ergonovine 0.2 mg/kg body weight can also cause coronary artery spasm in anesthetized dogs.

　　3. Coronary artery occlusion is the most common method to create myocardial infarction model. Usually use adult healthy dogs or rabbits. After anesthesia, open the chest cavity and ligate the anterior descending artery to block the blood supply of the myocardium and cause disease. Some people use a closed thoracic selective coronary artery catheter or heart. The catheter is inserted through the carotid artery incision of the anesthetized dog and extends along the vena cava wall to the bottom of the left sinus. , The tip is sent to a depth of about 2 cm in the left coronary artery, and 120 mg/kg mercury is injected into the catheter to form an acute myocardial infarction. Some people use the method of tracking the coronary arteries to completely block the coronary arteries, thereby forming rabbit models of acute ischemia and endangered myocardium. In order to deal with changes in myocardial ischemia in the natural state, several organizations have recently used conscious dogs as models of acute ischemia and infarction. First, anesthetize the dog, then separate the coronary arteries by about 10 mm, wear a coronary compression ring, block the blood flow of the coronary arteries by injecting water, observe the myocardial ischemic response and the effect of drugs when awake.. In addition, humans have used isolated large The mouse coronary artery was ligated to reconstruct the ultrastructure of the myocardial hypoxia model.