en Biomarkers (diagnosis & treatment) Biomarkers (diagnosis & treatment) Original Article Original Article <div style="text-align: justify;">Radiation-induced lung injury is one of the most prominent factors that interfere with chest cancer radiotherapy, and poses a great threat to patients exposed to total body irradiation. Upregulation of pro-oxidant enzymes is one of the main mechanisms through which the late effects of ionizing radiation on lung injury can be exerted. Interleukin (IL)-4 and IL-13 are two important cytokines that have been proposed to be involved in this process. Through stimulation of dual oxidase 1 and 2 <em>(DUOX1</em> & <em>2</em>), they induce chronic oxidative stress in irradiated tissues. In this study, we evaluated the effects of curcumin treatment on the regulation of <em>IL-4</em> and <em>IL-13</em>, <em>DUOX1</em> & <em>2 </em>genes as well as the pathological changes developed by this treatment. Twenty male Wistar rats were divided into four groups: radiation only; curcumin only; radiation + curcumin; and control group with neither pharmacotherapy nor radiation. Curcumin was administered for 4 and 6 consecutive days before and after irradiation, respectively. Also, the chest area was irradiated with 15 Gy using a cobalt-60 gamma rays source. All rats were sacrificed 67 days after irradiation followed by assessment of the levels of IL-4 and IL-13; the expression of IL-4 receptor-a1 (<em>IL4Ra1</em>), <em>IL13Ra2</em>, <em>DUOX1</em> and <em>DUOX2</em>, and finally the histopathological changes were evaluated. Radiation led to the increased level of IL-4, while the level of IL-13 showed no change. QPCR results showed the upregulation of<em> IL4Ra1</em>, <em>DUOX1</em> and <em>DUOX2</em> following lung irradiation. Histopathological evaluation also showed a remarkable increase in pneumonitis and fibrosis. Treatment with curcumin downregulated the expression of <em>IL-4</em>, <em>IL4Ra1</em>, <em>DUOX1</em> & <em>2</em>. Furthermore, it could mitigate pneumonitis and fibrosis following lung irradiation. The late effects of radiation-induced lung injury may be due to the upregulation of <em>DUOX1</em> & <em>2</em> genes. Curcumin, through modulation of these genes, may contribute to the protection against ionizing radiation.&nbsp;</div> Curcumin, radiation, radioprotection, DUOX1, DUOX2 212 219 http://ijmcmed.org/browse.php?a_code=A-10-1547-3&slc_lang=en&sid=1 Paiman Amini amini.peyman91@yahoo.com 100319475328460014126 100319475328460014126 No Nanobiotechnology Research Centre, Baqiyatallah University of Medical Sciences, Tehran, Iran. Hana Saffar saffar.hana281@yahoo.com 100319475328460014127 100319475328460014127 No Clinical and Anatomical Pathologist at Tehran University of Medical Science, Imam Khomeini Hospital Complex, Tehran, Iran. elahe motevaseli e-motevaseli@tums.ac.ir 100319475328460014128 100319475328460014128 No Department of Molecular Medicine, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran, Iran. masoud najafi najafi_ma@yahoo.com 100319475328460014129 100319475328460014129 No Radiology and Nuclear Medicine Department, School of Paramedical Sciences, Kermanshah University of Medical Sciences, Kermanshah, Iran. Ramezan Ali Taheri taherirm@bums.ac.ir 100319475328460014130 100319475328460014130 No Nanobiotechnology Research Centre, Baqiyatallah University of Medical Sciences, Tehran, Iran. Ali Qazvini qazvinia@bums.ac.ir 100319475328460014131 100319475328460014131 No Chemical Injuries Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran. Mohammad Reza Nourani r.nourani@yahoo.com 100319475328460014132 100319475328460014132 Yes Nanobiotechnology Research Centre, Baqiyatallah University of Medical Sciences, Tehran, Iran.