Effects of coal mine dust on lung function in rats

Objective: To explore the impacts of coal mine dust on lung function in rats, so as to provide the basis for the early prevention and treatment of coal worker's pneumoconiosis. Methods: Seventy-two SPF-grade 8-week-old male Sprague-Dawley rats were randomly divided into the coal dust group, the coal-silica dust group, the silica dust group and the control group. The rats in the first three groups of rats were administered 1 mL corresponding dust suspension into the lungs using non-exposure tracheal instillation, while the rats in the control group were administered 1 mL normal saline. Respiratory rate (f), forced vital capacity (FVC), peak expiratory flow (PEF) and dynamic pulmonary compliance (Cdyn) were measured at 1, 3 and 6 months after dust exposure. Lung tissues were collected to measure reactive oxygen species (ROS) and adenosine triphosphate (ATP) levels using corresponding ELISA kits and ATP assay kits, respectively. The relative mRNA expressions of peroxisome proliferators-activated receptor gamma coactivator 1-alpha (PGC-1α) and mitochondrial transcription factor A (TFAM) were detected using real-time fluorescent quantitative polymerase chain reaction assay. The relative protein expressions of PGC-1α and TFAM were detected using Western blotting. Results: There was no interaction between dust type and exposure duration on f (P>0.05), but there were interactions on FVC, PEF and Cdyn (all P<0.05). Compared with the control group at 6 months after dust exposure, the f of the rats in the silica dust group were increased, while the FVC and PEF of the rats in the coal-silica dust and silica dust groups were decreased, and Cdyn of the rats in the coal dust, coal-silica dust and silica dust groups were decreased (all P<0.05). There were interactions between dust type and exposure duration on ROS and ATP levels, the relative mRNA and protein expressions of PGC-1α and TFAM (all P<0.05). Compared with the control group at 3 and 6 months after dust exposure, the ROS levels in the rats in the coal dust, coal-silica dust and silica dust groups were increased, while the ATP levels, the relative mRNA and protein expressions of PGC-1α and TFAM were decreased (all P<0.05). Conclusion: The lung function impairment in rats caused by different types of coal mine dust is related to PGC-1α-mediated mitochondrial biogenesis dysfunction, which leads to increased ROS levels, decreased ATP and TFAM levels.