In addition, in the lung tissues of patients and mice with pulmonary fibrosis, the apoptosis levels of alveolar epithelial cells (AECs) were increased, the expression of acetyl-p53, PAI-1, and miR-34a was increased, and the expression of SIRT1 was decreased; however, the above process could be reversed by knockout of the miR-34a gene (Shetty et al., 2017). This evidence concerns the gene SIRT1 and pulmonary fibrosis.