Intraperitoneal injection of indole-3-acetic acid into emphysema model mice reduced the decreases in lung function, emphysema, tissue damage, collagen deposition, and levels of TNF-α, IL-1β, IL-6, and IL-17A.223 By comparing the differences in sputum bacteria between pneumoconiosis patients and controls, scientists found an increased percentage of Streptococcus, Granuliococcus, and Bacillus in pneumoconiosis patients. This evidence concerns the gene IL17A and pulmonary emphysema.