Introduction: When establishing a myocardial infarction model in rabbits, artificial ventilation under endotracheal intubation is required to prevent pulmonary collapse caused by pneumothorax. However, it is difficult to carry out endotracheal intubation due to the rabbit anatomy. We therefore attempted to develop a myocardial infarction model in rabbits without endotracheal intubation.
Materials and methods: A facial oxygen mask with a flow rate of 200 mL/min was placed on anesthetized rabbits (n = 17). The sternum was carefully incised along the midline to avoid injury to the parietal pleura. The major branch of the left coronary artery was then ligated and the surgical wound was closed. To investigate the effects of the surgical procedure on physiological parameters, blood pressure and blood gas were measured during the same procedure using 10 other rabbits.
Results: During the surgery, PaO(2) and PaCO(2) were stable at approximately 230 and 50 mm Hg, respectively. In addition, the animals did not experience severe ventilatory impairment. Four weeks after the myocardial ischemia, the overall mortality rate was 29.4% (5/17). All of the surviving animals showed Q-waves on ECG and myocardial infarction upon histological examination.
Conclusions: Our new method established a chronic rabbit model of myocardial infarction without the need for endotracheal intubation.