Attenuated Lung Fibrosis in Interleukin 6 Knock-out Mice after C-ion Irradiation to Lung

作者：Saito Fujita Tomoko; Iwakawa Mayumi^*; Nakamura Etsuko; Nakawatari Miyako; Fujita Hidetoshi; Moritake Takashi; Imai Takashi

来源：Journal of Radiation Research, 2011, 52(3): 270-277.

DOI：10.1269/jrr.10094

• IL-6
• C-ion
• Lung
• Fibrosis
• Mouse

There is a great deal of evidence that a cyclic cascade of inflammatory cytokines, together with the activation of macrophages, is initiated very early after irradiation to develop lung fibrosis in a late phase. To understand the persistent effects of cytokines, the cytokine gene of knock out or transgenic mouse is one of the useful tools. In this study, we evaluated a role of a key molecule, interleukin-6 (IL-6), in the late-phase inflammatory response and subsequent fibrotic changes after irradiation using wild-type (WT) and IL-6 knock out (IL-6 KO) mice. The mice underwent thoracic irradiation with 10 Gy of C-ion beam or sham-irradiation and were examined by histology. Immunoreactivity for IL-6 was induced at the site of bronchiolar epithelium, in pneumocytes and in monocytes by C-ion irradiation. At 24 weeks after irradiation, the infiltration of macrophages, detected by positive immunohistological staining with Mac3 antibody, was observed in alveolar spaces both in WT and IL-6 KO mice. The thickening of bronchiolar and alveolar walls exhibited in WT mice, but not KO mice, and fibrotic changes detected by Masson-Trichrome staining, were observed only in the lungs of WT mice, while it was attenuated in IL-6 KO mice. These results indicated that IL-6 might not be essential for activating macrophages in the late phase, but plays an important role for fibrotic changes of the alveolar wall after irradiation.

• 出版日期2011-5