DDIT3 and pulmonary fibrosis: Moreover, western bolt validation experiments also confirmed that C/EBP-homologous protein (CHOP), Heat Shock Protein 60 (HSP60), and Alpha smooth muscle actin(α-SMA) proteins were increased in expression related to this pathway at the extreme stage of fibrosis, suggesting that the disruption of ion balance in the endoplasmic reticulum induced by endoplasmic reticulum stress or the disturbance of protein processing and transportation were involved in the occurrence and development of pulmonary fibrosis in mice.