Document Type : Original Article
Departments of Medical Physics and Radiology, Faculty of Paramedical Sciences, Kashan University of Medical Sciences, Kashan, Iran
Department of Radiology, Faculty of Paramedical, Tehran University of Medical Sciences, Tehran, Iran
Clinical and Anatomical Pathologist at Tehran University of Medical Science, Imam Khomeini Hospital Complex, Tehran, Iran
4Department of Molecular Medicine, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran, Iran
5Department of Medical Radiation Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran
6Department of Medical Physics and Biomedical Engineering, Faculty of Medicine, Tehran University of Medical Sciences (International Campus), Tehran, Iran ;7Department of Physiology, College of Medicine, University of Mi
6Department of Medical Physics and Biomedical Engineering, Faculty of Medicine, Tehran University of Medical Sciences (International Campus), Tehran, Iran ;8Research Center for Molecular and Cellular Imaging, Tehran Univ
9Radiology and Nuclear Medicine Department, School of Paramedical Sciences, Kermanshah University of Medical Sciences, Kermanshah, Iran
The Lung is one of the most radiosensitive organs of the body. The infiltration of macrophages and lymphocytes into the lung is mediated via the stimulation of T-helper 2 cytokines such as IL-4 and IL-13, which play a key role in the development of fibrosis. It is likely that these cytokines induce chronic oxidative damage and inflammation through the upregulation of Duox1, and Duox2, which can increase the risk of late effects of ionizing radiation (IR) such as fibrosis and carcinogenesis. In the present study, we aimed to evaluate the possible increase of IL-4 and IL-13 levels, as well as their downstream genes such as IL4ra1, IL13ra2, Duox1, and Duox2.
Materials and Methods
In this experimental animal study, male rats were divided into 4 groups: i. Control, ii. Melatonin- treated, iii. Radiation, and iv. Melatonin (100 mg/kg) plus radiation. Rats were irradiated with 15 Gy 60Co gamma rays and then sacrificed after 67 days. The expressions of IL4ra1, IL13ra2, Duox1, and Duox2, as well as the levels of IL-4 and IL-13, were evaluated. The histopathological changes such as the infiltration of inflammatory cells, edema, and fibrosis were also examined. Moreover, the protective effect of melatonin on these parameters was also determined.
Results showed a 1.5-fold increase in the level of IL-4, a 5-fold increase in the expression of IL4ra1, and a 3-fold increase in the expressions of Duox1, and Duox2. However, results showed no change for IL-13 and no detectable expression of IL13ra2. This was associated with increased infiltration of macrophages, lymphocytes, and mast cells. Melatonin treatment before irradiation completely reversed these changes.
This study has shown the upregulation of IL-4-IL4ra1-Duox2 signaling pathway following lung irradiation. It is possible that melatonin protects against IR-induced lung injury via the downregulation of this pathway and attenuation of inflammatory cells infiltration.