2.3. Pulmonary Function

After the modeling period, the mice were tracheostomized, and the trachea was cannulated. Then, the cannula was connected to a computer-controlled small animal ventilator with a sealed glass cover. It was worth noting that the mice will be given the appropriate anesthesia before these operations. Generally, mice were anesthetized with 1% pentobarbital sodium 10 ml/kg body weight intraperitoneally, and the dose could be adjusted according to the difference of anesthetic tolerances. After endotracheal intubation, the pulmonary function of the mice was measured using the FlexiVent system (SCIREQ, Montreal, Quebec, Canada). The pulmonary function tests, forced expiratory volume at 0.05 s (FEV_0.05s) and forced vital capacity (FVC), were registered, while the FEV_0.05s/FVC was calculated.