动物造模,药效评价,心肌缺血 z-bio 2024-07-02 318

　　1. Animal modeling materials: Experimental miniature pigs, both male and female, weighing (16 ± 3.0) kg; Medication: pentobarbital; Instrument: RM-6008 8-channel physiological recorder.

　　2. Method of modeling: After intraperitoneal injection of pentobarbital anesthesia, it is fixed on the operating table in a supine position, and the trachea is cut open for assisted breathing. Cut open the sternum at the center, expose the heart, and sew the open center to make a hammock; Measure the length of the left anterior descending (LAD) branch of the coronary artery, free the artery at the junction of the lower one-third, and ligate it with a 4th line. Separate the common carotid artery and insert a catheter to connect a pressure transducer filled with heparin saline to measure arterial blood pressure; Insert a catheter into the left ventricle from the apex of the heart and measure left ventricular pressure (LVP) using a pressure transducer; LVP electrical signals are processed using a differentiator to record the rate of left ventricular pressure rise (dp/dt); Use subcutaneous needle electrode to record lead II electrocardiogram. The above parameters are synchronously recorded on the RM-6008 8-channel physiological recorder. Record the basic values of the above measurement indicators. Then ligate the LAD.

　　3. The principle of modeling is to establish an acute myocardial ischemia model by ligating the anterior descending branch of the left coronary artery through thoracotomy.

　　4. Changes in hemodynamics after modeling: After ligation of LAD, myocardial contractility decreased, manifested as Vmax and maximum rate of increase in left ventricular pressure dp/dt max decreasing at 15 and 30 minutes after ligation, respectively, and continuing until 120 minutes after ligation without returning to pre ligation levels. There were no significant changes in peak left ventricular pressure (LVP max), left ventricular end diastolic pressure (LVEDP), and mean arterial pressure (MAP) during each time period compared to before ligation. Heart rate (HR) starts to increase 15 minutes after ligation, reaches its peak at 30 minutes, and gradually returns to pre ligation levels after 90 minutes.

　　Epicardial electrocardiogram: ∑ ST significantly increased in various time periods after ligation, especially 30 minutes after ligation. During the early stage of ligation, frequent ventricular premature contractions can also be observed.

　　Myocardial infarction range: NB-T staining showed that the infarct range was (12.2 ± 4.0)% 6 hours after ligating the lower one-third of the LAD in pigs.

　　5. Precautions: Surgical instruments should be strictly disinfected to prevent surgical infections, surgical trauma should be minimized, and sterile operations should be strictly carried out.