Partial volume rat lung irradiation: Temporal fluctuations of in-field and out-of-field DNA damage and inflammatory cytokines following irradiation

Purpose: The current study investigated the early activation of inflammatory cytokines and macrophages in different regions of the lung following partial volume irradiation. We examined temporal fluctuations in DNA damage, cytokine expression and macrophage activation during 16 weeks post-irradiation. Materials and methods: We irradiated the lower lung of Sprague-Dawley rats with 10 Gy. A micronucleus assay was used to examine DNA damage. Real-time Reverse Transcription-Polymerase Chain Reaction (RT-PCR) was used to analyse the RNA expression of Interleukin-1 alpha (IL-1α), Interleukin-1 beta (IL-1β), Interleukin-6 (IL-6), Tumour Necrosis Factor alpha (TNF-α) and Transforming Growth Factor beta (TGF-β) relative to Glyceraldehyde-3-Phosphate Dehydrogenase (GAPDH). The activation of macrophages was determined using the antibody ED-1 for immunohistochemical analysis. Results: The expression of DNA damage, the activation of macrophages and the expression of inflammatory cytokines all fluctuated in a cyclic pattern. The initial induction of cytokine expression and the activation of macrophages occurred at very early times (1 h) following irradiation. Waves of cytokine expression and macrophage activation were also seen at later times (up to 16 weeks) following irradiation. DNA damage also occurred in a cyclic pattern though this was less pronounced out-of-field. The levels of cytokines and activated macrophages were elevated to a similar degree both in- and out-of-field, whereas there was a greater micronuclei yield in-field than out-of-field. Conclusions: An inflammatory response triggered by the partial volume irradiation occurs in the whole rat lung at very early times following irradiation and is maintained in a cyclic pattern to later times when the onset of functional symptoms is expected. We hypothesize that Reactive Oxygen Species (ROS) induced by this response play an important role in the induction of both in-field and out-of-field DNA damage.

[1]  N. Willich,et al.  Increased expression of pro-inflammatory cytokines as a cause of lung toxicity after combined treatment with gemcitabine and thoracic irradiation. , 2004, Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology.

[2]  Z. Liao,et al.  Spatial heterogeneity of the volume effect for radiation pneumonitis in mouse lung. , 1997, International journal of radiation oncology, biology, physics.

[3]  H. Kampinga,et al.  Pulmonary radiation injury: identification of risk factors associated with regional hypersensitivity. , 2005, Cancer research.

[4]  J. Hong,et al.  Rapid induction of cytokine gene expression in the lung after single and fractionated doses of radiation. , 1999, International journal of radiation biology.

[5]  M. Dewhirst,et al.  Overexpression of extracellular superoxide dismutase protects mice from radiation-induced lung injury. , 2002, International journal of radiation oncology, biology, physics.

[6]  S. Breit,et al.  Radiation and the lung: a reevaluation of the mechanisms mediating pulmonary injury. , 1995, International journal of radiation oncology, biology, physics.

[7]  Z. Liao,et al.  Damage and morbidity from pneumonitis after irradiation of partial volumes of mouse lung. , 1995, International journal of radiation oncology, biology, physics.

[8]  N. Willich,et al.  Modulation of radiation-induced tumour necrosis factor alpha (TNF-alpha) expression in the lung tissue by pentoxifylline. , 2002, Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology.

[9]  P. Rubin,et al.  Molecular biology mechanisms in the radiation induction of pulmonary injury syndromes: interrelationship between the alveolar macrophage and the septal fibroblast. , 1992, International journal of radiation oncology, biology, physics.

[10]  J. Van Dyk,et al.  Partial volume rat lung irradiation: an evaluation of early DNA damage. , 1998, International journal of radiation oncology, biology, physics.

[11]  I. Yeung,et al.  Partial volume rat lung irradiation; assessment of early DNA damage in different lung regions and effect of radical scavengers. , 2003, Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology.

[12]  P. Rubin,et al.  Differences in correlation of mRNA gene expression in mice sensitive and resistant to radiation-induced pulmonary fibrosis. , 1995, Radiation research.

[13]  H. Rodemann,et al.  Cellular basis of radiation-induced fibrosis. , 1995, Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology.

[14]  R. Jaszczak,et al.  Quantification of radiation-induced regional lung injury with perfusion imaging. , 1997, International journal of radiation oncology, biology, physics.

[15]  N. Willich,et al.  Dose-dependent induction of transforming growth factor beta (TGF-beta) in the lung tissue of fibrosis-prone mice after thoracic irradiation. , 2000, International journal of radiation oncology, biology, physics.

[16]  A. Churg An inflation procedure for open lung biopsies. , 1983, The American journal of surgical pathology.

[17]  D. Hallahan,et al.  Increased tumor necrosis factor alpha mRNA after cellular exposure to ionizing radiation. , 1989, Proceedings of the National Academy of Sciences of the United States of America.

[18]  N. Willich,et al.  Modulation of radiation-induced tumour necrosis factor α (TNF-α) expression in the lung tissue by pentoxifylline , 2002 .

[19]  Jacqueline P. Williams,et al.  INFLAMMATORY CELL RECRUITMENT FOLLOWING THORACIC IRRADIATION , 2004, Experimental lung research.

[20]  M. Epperly,et al.  Intratracheal injection of manganese superoxide dismutase (MnSOD) plasmid/liposomes protects normal lung but not orthotopic tumors from irradiation , 2000, Gene Therapy.

[21]  P. Rubin,et al.  Early and persistent alterations in the expression of interleukin-1 alpha, interleukin-1 beta and tumor necrosis factor alpha mRNA levels in fibrosis-resistant and sensitive mice after thoracic irradiation. , 1996, Radiation research.

[22]  R. Cartun,et al.  An Immunocytochemical Technique Offering Increased Sensitivity and Lowered Cost with a Streptavidin-Horseradish Peroxidase Conjugate , 1989 .

[23]  S. McDonald,et al.  A perpetual cascade of cytokines postirradiation leads to pulmonary fibrosis. , 1995, International journal of radiation oncology, biology, physics.

[24]  C. Marquette,et al.  Characterization of the Acute Inflammatory Response after Irradiation in Mice and its Regulation by Interleukin 4 (Il4) , 2001, Radiation research.

[25]  D. Clarençon,et al.  Acute induction of inflammatory cytokine expression after gamma-irradiation in the rat: effect of an NF-kappaB inhibitor. , 2004, International journal of radiation oncology, biology, physics.

[26]  P. Okunieff,et al.  Radiation pneumonitis and early circulatory cytokine markers. , 2002, Seminars in radiation oncology.

[27]  M. Dewhirst,et al.  Overexpression of extracellular superoxide dismutase reduces acute radiation induced lung toxicity , 2005, BMC Cancer.

[28]  J. Battista,et al.  In-field and out-of-field effects in partial volume lung irradiation in rodents: possible correlation between early dna damage and functional endpoints. , 2000, International journal of radiation oncology, biology, physics.

[29]  I. Yeung,et al.  Partial volume rat lung irradiation: the protective/mitigating effects of Eukarion-189, a superoxide dismutase-catalase mimetic. , 2006, Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology.

[30]  T. Buchholz,et al.  Accumulation of the common mitochondrial DNA deletion induced by ionizing radiation , 2004, FEBS letters.

[31]  N. Willich,et al.  Dose-dependent induction of transforming growth factor β (TGF-β) in the lung tissue of fibrosis-prone mice after thoracic irradiation , 1999 .

[32]  H Meertens,et al.  Loco-regional differences in pulmonary function and density after partial rat lung irradiation. , 2003, Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology.

[33]  Harm Meertens,et al.  Radiation damage to the heart enhances early radiation-induced lung function loss. , 2005, Cancer research.

[34]  N. Willich,et al.  The bronchiolar epithelium as a prominent source of pro-inflammatory cytokines after lung irradiation. , 2004, International journal of radiation oncology, biology, physics.

[35]  A small molecular weight catalytic metalloporphyrin antioxidant with superoxide dismutase (SOD) mimetic properties protects lungs from radiation-induced injury. , 2002, Free radical biology & medicine.

[36]  G. Hunninghake,et al.  Lung inflammation and fibrosis. , 1998, American journal of respiratory and critical care medicine.

[37]  T. Samulski,et al.  Radioprotection of Lungs by Amifostine is Associated with Reduction in Profibrogenic Cytokine Activity , 2002, Radiation research.

[38]  M. Anscher,et al.  Radiation-induced lung injury. , 2003, Seminars in radiation oncology.

[39]  J. P. Kamat,et al.  Oxidative damage to mitochondria in normal and cancer tissues, and its modulation. , 2000, Toxicology.

[40]  Z. Liao,et al.  Estimation of the spatial distribution of target cells for radiation pneumonitis in mouse lung. , 1997, International journal of radiation oncology, biology, physics.

[41]  N. Willich,et al.  Irradiation Induces a Biphasic Expression of Pro-Inflammatory Cytokines in the Lung , 2004, Strahlentherapie und Onkologie.

[42]  C. Hsu,et al.  Bronchoalveolar lavage and interstitial cells have different roles in radiation-induced lung injury , 2003, International journal of radiation biology.

[43]  Ž. Vujašković,et al.  Plasma TGFβ level in rats after hemithoracic irradiation , 1997 .