TNF and pulmonary fibrosis: The results showed that inflammatory factors TNF‐α, IL‐1β and IL‐6 expression were significantly up‐regulated by silica, which indicated that the rats still had significant inflammatory response 56 days after exposure to silica suspension, but after BMSCs treatment, both mRNA and protein levels of inflammatory factors were down‐regulated, suggesting that BMSCs had anti‐inflammatory effects in silica‐induced pulmonary fibrosis in rats.