The Experimental Study Of M2 Macrophages Inhibiting The Transformation Of BMSCs Into Myofibroblasts After Radiation

Objective: To investigate the inhibitory effect of M2 macrophages on the transformation of BMSCs into myofibroblasts after radiation.Methods: Bone marrow mesenchymal stem cells derived from SD rats and M2 macrophages polarized from macrophages were cultured separately,and their surface markers were identified by flow cytometry.First,a model of irradiated BMSCs in vitro was established,and then the irradiated BMSCs were randomly divided into three groups for research : group 1,the irradiated BMSCs were co-cultured with M2 macrophages through the Transwell chamber(3 μm);group 2,the irradiated BMSCs were co-cultured with M2 macrophages through the Transwell chamber(8 μm);group 3,irradiated BMSCs.The cell morphology of BMSCs in each group was observed under light microscope at the corresponding time.The cell proliferation ability was detected by CCK-8 method,and the live cells were screened and detected.Western blot was used to detect the expression levels of α-smooth muscle actin(α-SMA),NADPH oxidase(NOX4)and bone morphogenetic protein 2(BMP-2)of BMSCs in each group.Results: The mature macrophages can be obtained by adding M-CSF(macrophage colonystimulating factor)30 ng / ml to the bone marrow mesenchymal stem cell culture medium of SD rats for 6-9 days;the mature macrophages were induced to become M2 macrophages by 20 ng/ml IL-4(interleukin-4)for 24 h.After co-culture of irradiated BMSCs and M2 macrophages through the Transwell chamber(8 μm)for 48 hours,the expression levels of α-SMA and NOX4 in BMSCs were significantly reduced,and the expression levels of BMP-2 were increased(P < 0.05).Conclusion: M2 macrophages can reduce the production of α-SMA and NOX4 and promote the expression of BMP-2 in BMSCs after irradiation,and inhibit the transformation of BMSCs into myofibroblasts after radiation,which may have a potential therapeutic effect on the osteoradionecrosis of jaws.