疾病动物模型,结扎法心肌梗死模型 z-bio 2021-10-14 257

　　[Modeling mechanism] Through ligation, the coronary arteries of the model animals are stenosis or occlusion, and the myocardium supplied by the coronary arteries is ischemia and necrosis, thereby causing myocardial infarction in the model animals.

　　[Modeling method] In short, general coronary artery ligation can be divided into three main steps: first, after the animal is anesthetized, the left atrium is operated in the fourth intercostal space, and then the pericardium is carefully opened, and the left pericardium is bandaged. If the ligation is successful, the anterior descending coronary artery (left anterior descending branch, LAD) at the distal end of the left atrial appendage. An electrocardiogram (ECG) shows a typical ST elevation, which turns white when observing the anterior wall of the left ventricle, and finally closes the chest cavity. If you need to model myocardial ischemia-reperfusion injury, ligating the LAD and then ligating after 30 minutes may result in ischemia-reperfusion injury. The specific modeling method takes the following animals as an example.

　　Boar: Choose a piglet weighing 18-22 kg, and first apply 30 g/L pentobarbital to the ears of the pig in a 3-5 ml bolus dose to soothe the pig. For 5 minutes, the pig was unstable and lay down. Then a trocar was used to quickly establish a vein leading to the pig ear vein, and after a slow bolus injection of 30 g/L pentobarbital (1 ml/kg) after anesthesia, the animal was placed on the operating table on its back. local. In the intervention room. The trachea is separated and exposed and cannulated into the trachea. Connect the ventilator. Open the chest along the fourth intercostal space of the sternum to expose the heart, lift the pericardium, make a longitudinal incision, and make a pericardial bed. At the junction of the middle and lower 1/3 of the LAD torso, tie a silk thread underneath for ligation. Four multi-point fixed epicardial electrode linings were sewn on the surface of the heart. A multi-channel physiological recorder was used to record the epicardial potential before and after ligation, and ST elevation was used as the criterion for the success of the model. Close the chest cavity and pull out the ventilator.

　　Dogs: Beagle dogs weighing 10-18 kg are usually used. The animals are weighed, and 3% sodium pentobarbital 30 mg/kg is administered intravenously for anesthesia and placed on the operating table on the right side, and fixed. The trachea is intubated and connected to the ventilator. Open the chest along the 4th or 5th intercostal space along the left edge of the sternum to expose the heart, cut the nipple, and form the pericardial bed. Separate the middle and lower 1/3 of the LAD trunk line, and tie it with silk thread below. A multi-point fixed epicardial electrode lining was sutured on the surface of the heart, a multi-channel physiological recorder was used to record the epicardial potential map before and after ligation, and ST elevation was used as the criterion for the success of the model. Close the chest cavity, pull out the ventilator, and handle the animal as needed. Rats: Adult Wistar rats weighing about 250g and pentobarbital sodium 10ml/kg are selected for intraperitoneal injection, and 20-30μg/kg of atropine is injected intraperitoneally before intubation. First, the trachea is intubated and connected to the ventilator. Fix the limbs of the rat in the supine position and remove the hair. The upper boundary is at the level of the upper boundary of the sternum, and the lower boundary is at the level of the sternum. The lower edge of the breastbone. After sterilization, a longitudinal incision of about 1.5-2.0 cm is made along the left edge of the sternum at the center of the strongest point at the top, and the chest cavity is opened layer by layer to enter the chest cavity. Cut the open heart capsule to expose the left atrial appendage, and insert a needle 2-3 mm below the left atrial appendage. The midpoint of the ligation is at the junction of the left atrial appendage and the pulmonary artery cone. The ligation direction is parallel to the end of the left atrial appendage and perpendicular to the atrioventricular junction. The insertion depth of the needle is 1.5 to 2.0 mm. Since the coronary arteries of rats are small and it is difficult to separate the myocardium, they are usually sutured and ligated with a portion of the myocardium. The binding strength is moderate to prevent damage. Myocardium or blood vessels. Return the heart to the chest cavity and quickly suture the chest wall. Stop artificial respiration. Signs of successful modeling are heart wall bleaching and ECG monitoring ST elevation.

　　Mouse: Use a mouse of 25 to 30 grams. Pentobarbital sodium (50 mg/kg) was injected intraperitoneally. After the mouse is anesthetized, paste it on the control panel. The chest hair was shaved, sterilized with 70% ethanol, and a 22G trocar was placed in the trachea under direct vision to reconstruct the airway. The breathing rate is set to 100-110 breaths/minute. Take the midline of the left sternum perpendicular to the ribs and cut the skin. The pectoralis major and pectoralis minor muscles are divided into several layers, and the third, fourth, and fifth ribs are removed during the exhalation phase of the mouse. Use a chest opener to support and fix the sternum, expose the heart and cut the sternum. capsule. Look for the left anterior descending artery under a microscope, and suture about 1 mm with 10.0 ophthalmic sutures at the lower end of the left atrium, with a span of about 1 mm, and ligate the left anterior descending artery. Observe the changes of ECGST-T and the color of myocardium. Remove the chest opener and close the chest cavity with 8-0 non-invasive sutures. After the operation, the skin was sutured and the ventilator was maintained for about 30 minutes. After waking up, the mice were weaned. [Model Features] Coronary artery ligation is the most commonly used method to replicate myocardial infarction models, and it is also a recognized model for studying myocardial ischemic injury. The scope of ligation methods for establishing myocardial infarction animal model is very clear, and the effect is very accurate. Different regions of the heart can be modeled according to research needs, and the model can be monitored and evaluated in real time through electrocardiogram, pathology and serum. Enzymology, etc. However, the ligation method requires thoracotomy in the animal and involves operations such as tracheal intubation, anesthesia, and post-operative care. The process is very complicated and requires complicated surgical techniques and equipment, so it is not suitable for general laboratory modeling research. The trauma is great, and the impact on animals is also great. In addition, the higher postoperative animal mortality further increases the cost of modeling. Some studies have shown that postoperative animal mortality may be as high as 60%.

　　[Model Evaluation and Application] Clinically, most myocardial infarctions are caused by coronary atherosclerosis. Thrombus formation after bleeding from unstable atherosclerotic plaque is the pathological basis of coronary artery occlusion. Since 50% of human myocardial ischemia occurs in the blood supply area of the left anterior descending branch, the animal model of acute myocardial ischemia caused by coronary artery ligation has a high degree of clinical similarity. Hemodynamics and myocardial metabolism after myocardial ischemia are used to study drugs for the prevention and treatment of myocardial ischemia. However, myocardial infarction caused by ligation does not have this pathological basis, and thoracotomy will cause physiological and biochemical changes in animals. Therefore, there are certain differences between model animals and clinical myocardial infarction. However, there is still a specific application space for precise modeling effects and precise control of connection methods. This model is suitable for studies that require clinical simulation of changes in myocardial injury or studies that require precise control of the time and degree of infarction. Because the modeling process is relatively complex, it must be performed by a laboratory with specific surgical instruments and technical foundations.