Abstract:Background and Aim Animal models of myocardial infarction (MI) had been widely used to study the pathological and physiological changes that occur in MI, and to objectively evaluate the efficacy of new treatments. They were an important tool in this procedure. However, the mortality rate of MI animal models had so far been higher than in real-life situations. The aim of this study was to explore the use of a modified retrograde traction tracheal intubation (MRTI) method for increasing the success rate of MI models in rats. Methods 125 male Sprague-Dawley rats were used in the experiment. Using the MRTI method and the breath tube intubation (BTI) method to establish artificial airway, we established the MI model by ligation of the left anterior descending branch of the coronary artery. At week 4 after induction of the MI in rat model, the cardiac structure and left ventricular ejection fraction (LVEF) were assessed by echocardiography. After the animals were sacrificed, cardiac collagen volume fraction (CVF) was evaluated by Masson staining. We analyzed the effects of MRTI, the use of lidocaine, operative details, nursing considerations during the operation, and post-operative factors on the success rate of the MI model in rats. Results The success rate of establishing artificial airway by using MRTI (100%) was higher than that by using BTI (85%). The success rate of generating a MI model in rats could be significantly increased using the following methods: (1)Setting up the artificial airway through the use of MRTI by using a single-lumen central venous catheter (2)Selecting a ligation site: 2 mm below the midpoint of the connection between the left atrial appendage and the pulmonary cone (3)Adding a drop of lidocaine to the surface of the heart to slow down the heart rate, to make the operation easier to perform, and to prevent arrhythmias postoperatively (4)Clearing up airway secretions timely both intra and postoperatively (5)Making sure that rats were in a warm state both intra and postoperatively (6)Preventing wound infection. Four weeks later, echocardiography showed that compared with normal rats, MI rats’ left ventricular end-systolic diameter was increasing, left ventricular posterior wall was compensatory hypertrophy, LVEF was reduced, and cardiac CVF was increasing These indicators differences had no statistical significances between the two groups. For the success rate of rat myocardial infarction model, MRTI group (76.7%) was higher than BTI group (65.0%). Conclusions Use of the MRTI method can quickly establish an artificial airway in rats.