心律失常,冠状动脉结扎 z-bio 2021-03-18 501

　　(1) Reproduction method Male rats weighing 250-350g were anesthetized with ether and fixed in the supine position. Cut the skin in the middle of the neck, separate the trachea for tracheal intubation, connect to an artificial ventilator for artificial respiration, maintain the ventilation at 15-20ml/kg body weight, and breathe at 50-60 times/min. Pass through a three-way tube and contain ether The anesthesia bottle is connected to maintain anesthesia. Preoperative subcutaneous injection of atropine 0.2mg/only can reduce the secretion of respiratory secretions. Separate the left common carotid artery, insert an arterial cannula into the heart, connect a pressure transducer, and inject heparin saline (1500U/ml) into the lumen to prevent blood clotting in the tube. Separate the left external jugular vein and insert a soft plastic tube with a diameter of 0.5 to 1 mm for drug injection. Remove the left chest hair, make a 2cm transverse incision along the fourth intercostal space, bluntly separate the pectoralis major and pectoralis minor muscles, cut the thoracic cavity to the left along the fourth intercostal space on the left edge of the sternum, and cut the pericardium to expose the heart. Thread a No. 0 silk thread under the left anterior descending branch of the coronary artery. Pass the two ends of the silk thread through two small plastic rings (3mm in diameter) connected together, and then pass the two ends together through a hard plastic with a diameter of 1 to 2 mm. Use a trocar to puncture the chest wall from the inside to the outside and reach the back through the two shoulder blades. Lead the hard plastic tube out of the chest cavity to the back. Withdraw the trocar. Keep the plastic tube in the chest cavity and align the inside with the coronary artery. After the outer end of the plastic tube is fixed, it is connected to the electronic peristaltic pump for continuous negative pressure suction for 2 hours, sucking out the blood and gas in the chest cavity, quickly closing the chest cavity under positive pressure breathing, suture the chest wall muscle and skin layer by layer, remove the tracheal intubation, and stop the inhalation Ether and artificial respiration, after the animal breathes smoothly, the trachea and neck skin are sutured. The placement of the limb lead electrodes is to insert a stainless steel wire with a diameter of 0.5mm and a length of about 5cm into the 8 gauge needle wire and bend it into a 3mm hook, and pierce the left lower limb and right upper limb under the outer skin. The hooks are fixed behind the subcutaneous tissue. , Withdraw the needle and keep the wire electrode for recording the ECG. On the 5th day after the operation, the animal was placed in a small wooden basin, electrodes were connected, lead II electrocardiogram was recorded, and the common carotid artery cannula was connected to a pressure transducer to record blood pressure. After the animal moves naturally for 30 minutes, the coronary artery is ligated. The method is that the operator holds the plastic tube with the ligation thread in his left hand, and gradually tightens the double-strand ligation thread with the right hand, so that the plastic tube pushes two plastic rings to compress and occlude the coronary artery, and then fix the ligation. line. Ventricular premature beats usually begin 4 to 6 minutes after ligation, followed by ventricular tachycardia and ventricular fibrillation. Some animals may suddenly experience ventricular fibrillation and die. The severity of arrhythmia peaks at 8-10 minutes, and fatal ventricular fibrillation often occurs at 6-11 minutes. After 10 minutes, the arrhythmia gradually decreases and disappears naturally after 20 minutes. The animals were sacrificed 6 hours after the coronary artery was ligated, the heart was quickly taken out, the atrium and the right ventricle were cut off, placed in the refrigerator for 1 hour, and the ventricle was cut into 5 pieces of equal thickness parallel to the coronary sulcus under the coronary artery ligation line, and 0.1% nitro was added. In a tetrazolium blue (N-BT) solution, shake and dye for 10 min in a constant temperature water bath at 37°C. The normal myocardium is stained dark blue, and the infarcted myocardium is not colored light red. Trace, scan, use Osiris software to calculate the percentage of the infarcted area to the left ventricular area, and observe the effect of the drug on the myocardial infarcted area.

　　(2) Model characteristics The arrhythmia of coronary artery ligation in conscious rats is similar to that of anesthetized rats, but the degree is more serious. The incidence of ventricular fibrillation and death risk coefficient of conscious rats are higher than those of anesthetized rats. And you can observe the intervention effects of animal autonomic nerves and sympathetic nerves when arrhythmia occurs in the awake state.

　　(3) Comparative medicine. Under the conditions of anesthesia and artificial respiration, opening the thorax and ligating the coronary arteries to cause myocardial ischemic arrhythmia is a simple method with a high success rate to study antiarrhythmic drugs, but under anesthesia, cardiovascular function and Nerve reflexes are suppressed, and the type of anesthetic and the depth of anesthesia will affect the arrhythmia. The model established by this method can overcome the above-mentioned shortcomings and provide an animal experiment method for the study of the body's self-regulatory function during the onset of the human body.