CpG-ODN prevent pulmonary fibrosis by regulating the expression of Th1/Th2 cytokines

To investigate the mechanism of CpG-ODN in the prevention of radiation pulmonary fibrosis by focusing on the regulation of balance between Th1/Th2 cytokines. The entire thorax of female C57BL/6 mice was exposed to a single radiation at a dose of 15 Gy. The Th1/Th2-related cytokines and profibrogenic cytokines were detected by enzyme linked immunosorbent assay for 20 weeks after radiation. Alveolar macrophages, pulmonary fibrosis, and phosphorylated Mitogen-activated protein kinase (MAPK) family proteins were detected by immunohistochemistry. The results suggested that CpG-ODN promoted Th1-related cytokine secretion and inhibited Th2-related cytokine secretion, leading to a predominantly Th1 immune response, reduced alveolar macrophage accumulation, and profibrogenic cytokine (TGF-β1 and IGF-1) expression, which may be involved in the inhibition of phosphorylation of MAPK family proteins. This indicates that CpG-ODN prevents pulmonary fibrosis by regulating the imbalance between Th1/Th2 after irradiation. (authors)