Fractionated irradiations lead to chronic allergic airway inflammation through increasing the influx of macrophages
In our previous study, repeated irradiations showed persistent depression of immune response, especially Th1-related immune response. Here, we hypothesized and determined that irradiation may exacerbate development of allergic airway inflammation.
C57BL/6 mice were irradiated repeatedly at 1 Gy or 0.5 Gy. At 6 months after irradiation, mice were sensitized and challenged short-term with OVA. Antigen-specific immunoglobulins, the percentages of inflammatory cells, chemokine expression, cytokine levels, and collagen deposition were tested.
In irradiated mice, IgG2a in serum was lower when compared with that of control mice, while IgG1 was significantly higher. Interestingly, the percentages of macrophages in bronchoalveolar lavage fluid (BALF) and the lung of irradiated mice were significantly higher. Conversely, the percentages of neutrophil were significantly lower in BALF of irradiated mice. In the lung of irradiated mice, MCP-1 and IP-10 for attraction of macrophages showed the higher expression level, but KC expression for neutrophils showed no difference. Next, TGF-β1 and IL-17A in BALF were higher in irradiated mice. In addition, phosphorylated-Smad2/3 was increased in irradiated mice. Finally, the deposition of collagen was increased in irradiated mice.
Our study showed that fractionated irradiation lead to the chronic allergic airway inflammation through increasing the influx of macrophages and active TGF-β levels.
KeywordsIonizing radiation Fractionated irradiations Airway inflammation Asthma Chronic inflammation
This work was supported by creative research project funded from Korea Atomic Energy Research Institute (KAERI), Korea.
Conflict of interest
The authors declare that they have no competing interests.
- 2.Tago F, Tsukimoto M, Nakatsukasa H, Kojima S. Repeated 0.5 Gy gamma irradiation attenuates autoimmune disease in MRL-lpr/lpr Mice with suppression of CD3+CD4-CD8-B220+ T-cell proliferation and with up-regulation of CD4+CD25+Foxop3+ regulatory T cells. Radiat Res. 2008;169:59–66.PubMedCrossRefGoogle Scholar
- 12.Bousquet J, Jeffery PK, Busse WW, Johnson M, Vignola AM. Asthma. From bronchoconstriction to airways inflammation and remodeling. Am J Respir Cri Care Med. 2000;161:1720–45.Google Scholar