To explore the relationship between ER stress and myofibroblast transformation of LR-MSC during lung fibrosis, we introduced TGFβ1, a classic profibrotic growth factor, and tunicamycin (TM) to induce myofibroblast transformation and ER stress of LR-MSC in vitro, respectively. The gene discussed is TGFB1; the disease is pulmonary fibrosis.