MRC1 and chronic obstructive pulmonary disease: In this study, we detected the changes in the number of M2-type macrophage-associated autophagy-positive cells in lung tissues of mice from control group and COPD model group by double immunofluorescence method, using CD206 to label M2 macrophages, LC3B to label autophagy-associated protein, and found that CD206+LC3B+ cells were significantly higher in the COPD group compared with the control group, which was statistically significant (p<0.05, Supplementary file Figures 2A and 2B), indicating that M2 macrophages are closely related to autophagy.