动物造模,药效评价,心肌梗死 z-bio 2024-09-06 956

　　1. Modeling material animals: Wistar rats, male or female, weighing 150-250g; Medications: Ketamine, Penicillin; Equipment: BL-420 biological function experimental system, animal artificial ventilator, 1411 small high-frequency knife.

　　2. Modeling method: Wistar rats were anesthetized with intraperitoneal injection of 100mg/kg ketamine, and an oral cannula was connected to an animal ventilator with a respiratory ratio of 1:1, a frequency of 80/min, and a tidal volume of approximately 14-16ml/kg. Make an oblique incision along the left side of the sternum, sequentially incise the skin, superficial fascia, and deep fascia, and use hemostatic forceps to bluntly separate the pectoralis major muscle and serratus anterior muscle at the junction. Use hemostatic forceps to bluntly separate the 3rd and 4th intercostal spaces near the sternum to enter the chest, and open the intercostal spaces to expose the heart. Lift the pericardial wall layer with tweezers, then carefully cut the pericardium with small scissors. Use a cotton swab to push the thymus upwards and locate the left coronary vein at a distance of about 3mm from the aortic root between the lower edge of the left atrial appendage and the pulmonary artery cone. Using this as a marker, place the electrocautery electrode of the 1411 small high-frequency knife in the deep part of the anterior descending branch of the left coronary artery and electrocoagulate for 1-2 seconds. Observing the dynamic changes of electrocardiogram using BL-420 biological function experimental system, if the ST segment is raised by more than 0.2mV in two or more limb leads with corresponding lead changes, and the electrocoagulation area turns gray white under naked eye observation, it can be preliminarily judged that the surgery is successful. Carefully examine the heart, and if there is no bleeding, close the chest. Postoperative intramuscular injection of 400000 U of penicillin to prevent infection.

　　3. The production of animal models of myocardial infarction is an important means of studying the mechanisms of occurrence, development, and treatment of myocardial infarction. A myocardial infarction model was replicated by electrocoagulation using a 1411 high-frequency knife.

　　4. Pathological changes after modeling: Tissue sections of myocardial necrosis area 12 hours after surgery showed that the cell outline remained intact, the cytoplasm showed obvious eosinophilic color, the transverse stripes disappeared, and nuclear condensation, fragmentation, and dissolution were visible. Neutrophils infiltrated the infarct area, showing typical coagulative necrotic changes. In normal myocardial tissue slices, the morphology of myocardial cells is intact, with clear boundaries, clear horizontal stripes in the cytoplasm, and oval shaped nuclei. Two days after surgery, granulation tissue can be seen growing into the infarcted lesion from the surrounding area, with white blood cells and macrophages exuding around the lesion. Two weeks after surgery, the infarcted lesion was replaced by granulation tissue and turned into a scar.

　　5. Precautions: Surgical instruments should be strictly disinfected to prevent surgical infections, surgical trauma should be minimized, and aseptic operation should be strictly enforced.