[Changes of lung function and inflammatory factors in rat models of coal workers' pneumoconiosis]

Objective: To observe the changes of lung function and inflammatory factors in rat models of coal workers' pneumoconiosis at different time points. Methods: In June 2021, 96 healthy male SD rats with SPF grade were divided into 1, 3, and 6-month control group and dust staining group (coal dust group, coal silica dust group, quartz group) according to random number table method, with 8 rats in each group. After one week of adaptive feeding, a one-time non-exposed tracheal perfusion method (1 ml/ piece) was used. The dust dyeing group was given 50 g/L coal dust, coal silica mixed dust and quartz dust suspension, respectively, and the control group was given 0.9% normal saline solution. At 1, 3 and 6 months after perfusion, lung function was detected by animal lung function apparatus, then all lung tissues and alveolar lavage fluid were killed, and lung histopathological morphological changes were observed by HE staining, and the contents of interleukin (IL-1β), IL-18, IL-4 and IL-10 in alveolar lavage fluid were detected by ELISA. One-way analysis of variance was used to compare groups. Two factors (inter-group treatment factor (4 levels) and observation time factor (3 levels) ) were used in the analysis of the effects of inter-group treatment and treatment time on related indicators. Results: HE staining results showed that coal spot appeared in the lung tissue of coal dust group, coal spot and coal silicon nodule appeared in the lung tissue of coal dust group, and silicon nodule appeared in the lung tissue of quartz group. Compared with the control group, the forced vital capacity (FVC) and forced expiratory volume at 0.2 second (FEV(0.2)) of rats in the dust staining group had interaction between the treatment and treatment time (P<0.05). With the increase of dust dyeing time, FVC and FEV(0.2) decreased significantly at 3-6 months of dust dyeing, and the maximum gas volume per minute (MVV) decreased significantly at 1-3 months of dust dyeing (P<0.05). The lowest lung function index was in quartz group, followed by coal-silica group and coal-dust group. There were statistically significant differences in the main effect and interaction effect of the pro-inflammatory factor IL-18 among all groups in treatment and treatment time (IL-18: F=70.79, 45.97, 5.90, P<0.001), and interaction existed. The highest content of inflammatory factors in alveolar lavage fluid of all dust groups was quartz group, followed by coal silica group and coal dust group. There were significant differences in the main effect and interaction effect of anti-inflammatory factors between groups and treatment time (IL-4: F=41.55, 33.01, 5.23, P<0.001, <0.001, <0.001; IL-10: F=7.46, 20.80, 2.91, P=0.002, <0.001, 0.024), and there was interaction. The highest content of anti-inflammatory factor was in quartz group, followed by coal silica group and coal dust group. Conclusion: Lung function decreased and levels of inflammatory fators increased in rat models of coal workers' pneumoconiosis, with the quartz group being the most severely damaged. Lung function is mainly impaired in thrid-six months, and the content of inflammatory factors begins to change in first-thrid months. MVV are the earliest and most obvious in lung function. IL-18 is suitable for monitoring changes in the pro-inflammatory response of coal workers' pneumoconiosis, and IL-10 is suitable for monitoring changes in anti-inflammatory response.