【Animal Modeling】-How to build an animal model of inhalation of atmospheric fine particles?

  Objective: To establish an animal model of physical injury caused by long-term inhalation of atmospheric particulate matter (PM2.5) aerosols.

  Method: Prepare a PM2.5 aerosol continuous inhaler. Different concentrations (100±10μg/m3, 150±10μg/m3, 200±10μg/m3), different time (1 week, 2 weeks, 4 weeks, 8 weeks, 12 weeks) and different methods (intratracheal) Study the effects of exposure). Perfusion and aerosol inhalation methods) and the effects of different animals (Wistar rats, BN rats and guinea pigs) on the establishment of the model. Observe the general condition of the animals and calculate weight gain and mortality. Test lung function, such as respiratory rate, forced expiratory volume, vital capacity ratio (FEV1/FVC), arterial blood oxygen partial pressure (PO2) and counting bronchoalveolar lavage fluid (BALF)) cell classification; optical microscopy to check pathology. We believe that pneumonia in the pathology of trachea and lung tissue is the standard for establishing a successful model, and determine the influencing factors of the establishment of the model. Results: After inhaling different concentrations of PM2.5 aerosol for eight consecutive weeks, Wistar rats became addicted, lost weight, and increased the total number of white blood cells and monocytes in bronchoalveolar lavage fluid (BALF). The increase in the proportion of macrophages showed that the lung function index showed an increase in respiratory frequency, arterial blood PO2 and FEV1/FVC decreased, and pathology showed changes in trachea and lung tissue inflammation and pulmonary fibrosis. Changes in inflammation are positively correlated. The exposure concentration is high, but the high concentration shows a high mortality rate. When Wistar rats at the same concentration were inhaled for different periods of time (1 week, 2 weeks, 4 weeks, 8 weeks, and 12 weeks), starting from 8 weeks, the trachea and lung tissues of the addicted animals changed significantly. no difference. few weeks. Wistar rats were inhaled by different methods (unexposed intratracheal perfusion and aerosol inhalation) for 8 consecutive weeks. The two methods have the same effect, but the inhalation method has lower animal mortality. Wistar rats, BN rats and guinea pigs were continuously inhaled for 8 weeks. The effects of these three animals are comparable, but the mortality rate of Wistar rats is very low.

  Conclusion: Using Wistar rats to inhale PM2.5 aerosol with a concentration of 150±10μg/m3 for 8 consecutive weeks can establish an animal model suitable for PM2.5-induced bodily injury. It is not only a large-scale model in China, but also has the characteristics of Fujian Province, and the personal injury model caused by PM2.5 promotes the development of PM2.5 prevention and treatment measures.