A Silicosis Mouse Model Established by Repeated Inhalation of Crystalline Silica Dust

Silicosis can be caused by exposure to respiratory crystalline silica dust (CSD) in an industrial environment. The pathophysiology, screening, and treatment of silicosis in humans have all been extensively studied using the mouse silicosis model. By repeatedly making mice inhale CSD into their lungs, the mice can mimic the clinical symptoms of human silicosis. This methodology is practical and efficient in terms of time and output and does not cause mechanical injury to the upper respiratory tract due to surgery. Furthermore, this model can successfully mimic acute/chronic transformation process of silicosis. The main procedures were as follows. The sterilized 1-5 µm CSD powder was fully ground, suspended in saline, and dispersed in an ultrasonic water bath for 30 min. Mice under isoflurane-induced anesthesia switched from shallow rapid breathing to deep, slow aspiration for approximately 2 s. The mouse was placed in the palm of a hand, and the thumb tip gently touched the lip edge of the mouse's jaw to straighten the airway. After each exhalation, the mice breathed in the silica suspension drop by drop through one nostril, completing the process within 4-8 s. After the mice's breathing had stabilized, their chest was stroked and caressed to prevent the inhaled CSD from being coughed up. The mice were then returned to the cage. In conclusion, this model can quantify CSD along the typical physiological passage of tiny particles into the lung, from the upper respiratory tract to the terminal bronchioles and alveoli. It can also replicate the recurrent exposure of employees due to work. The model can be performed by one person and does not need expensive equipment. It conveniently and effectively simulates the disease features of human silicosis with high repeatability.