Mesenchymal stem cells-extracellular vesicles alleviate pulmonary fibrosis by regulating immunomodulators

Figure 7 Mesenchymal stem cells-extracellular vesicles can inhibit the inflammatory response in the process of pulmonary fibrosis. A: The expressions of nuclear factor-kappaB (NF-κB) p65 and interleukin (IL)-1β in A549 cells of each group were verified by western blot; B and C: The statistical analysis of the expression levels of each protein. MSV-EVs can’t induce an immune inflammatory response (P > 0.05). Transforming growth factor (TGF)-β can induce the immune inflammatory response of cells (NF-κB p65: ^dP < 0.05 vs control group; IL-1β: ^eP < 0.01 vs control group). However, mesenchymal stem cells-extracellular vesicles (MSC-EVs) can reverse the immune inflammatory response caused by TGF-β (NF-κB p65: ^aP < 0.05; IL-1β: ^aP < 0.05); D: The expression of IL-1β in lung tissue was observed by immunohistochemical (IHC) staining; E: The statistical analysis of the expression level of IL-1β in IHC staining. On day 14 and day 28, IL-1β (14 d: ^fP < 0.001 vs sham group; 28 d: ^fP < 0.001 vs sham group) deposition was observed in the bleomycin + phosphate buffered saline group, and the above pathological changes could be reversed after MSC-EVs treatment (14 d: ^cP < 0.001; 28 d: ^cP < 0.001); F: The western blot results of each protein’s expression in mice’s lung tissue in each group; G-I: The statistical analysis of western blot results of each protein in mouse lung tissue. No matter whether on day 7, 14, or 28, the expression of immune inflammatory response gene-related nuclear factor-kappaB (NF-κB) p65 (7 d: ^dP < 0.05 vs sham group; 14 d: ^eP < 0.01 vs sham group; 28 d: ^dP < 0.05 vs sham group), IL-2 (7 d: ^eP < 0.01 vs sham group; 14 d: ^fP < 0.001 vs sham group; 28 d: ^eP < 0.01 vs sham group) and IL-1β (7 d: ^eP < 0.01 vs sham group; 14 d: ^dP < 0.05 vs sham group; 28 d: ^dP < 0.05 vs sham group) in lung tissue of mice was significantly higher than that in the sham group. After MSC-EVs treatment, the expression of NF-κB p65, IL-2, and IL-1β decreased significantly at 7 d (NF-κB p65: ^aP < 0.05; IL-2: ^cP < 0.001; IL-1β: ^bP < 0.01) in the acute phase, 14 d in subacute phase (NF-κB p65: ^bP < 0.01; IL-2: ^cP < 0.001; IL-1β: ^aP < 0.05) and 28 d in chronic phase (NF-κB p65: ^aP < 0.05; IL-2: ^cP < 0.001; IL-1β: ^aP < 0.05). MSC: Mesenchymal stem cell; EV: Extracellular vesicle; BLM: Bleomycin; PBS: Phosphate buffered saline; TGF: Transforming growth factor; NF-κB: Nuclear factor-kappaB; IL: Interleukin.