Fractionated irradiations lead to chronic allergic airway inflammation through increasing the influx of macrophages.
OBJECTIVE
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.


METHODS
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.


RESULTS
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.


CONCLUSIONS
Our study showed that fractionated irradiation lead to the chronic allergic airway inflammation through increasing the influx of macrophages and active TGF-β levels.
Radiation Division for Biotechnology, Advanced Radiation Technology Institute, Jeongeup Campus of Korea Atomic Energy Research Institute (KAERI), 1266 Sinjeong-dong, Jeongeup-si, Jeonbuk, Republic of Korea. hrpark@kaeri.re.kr
Hae-Ran
HR
Park
Sung-Kee
SK
Jo
Dong-Kyung
DK
Yu
Uhee
U
Jung
D000818:Animals; D001249:Asthma / Q000209:etiology*; D002908:Chronic Disease; D003094:Collagen / Q000378:metabolism; D019583:Dose Fractionation, Radiation; D005260:Female; D007073:Immunoglobulin E / Q000096:biosynthesis; D007074:Immunoglobulin G / Q000096:biosynthesis; D007371:Interferon-gamma / Q000032:analysis; D020381:Interleukin-17 / Q000032:analysis; D015847:Interleukin-4 / Q000032:analysis; D008264:Macrophages / Q000502:physiology / Q000528:radiation effects*; D051379:Mice; D008810:Mice, Inbred C57BL; D053773:Transforming Growth Factor beta1 / Q000502:physiology
D007074:Immunoglobulin G; D020381:Interleukin-17; D053773:Transforming Growth Factor beta1; D015847:Interleukin-4; D007073:Immunoglobulin E; D007371:Interferon-gamma; D003094:Collagen