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Cell cycle dependent modulating effects of melatonin on radiation induced cytogenetic damages in lymphocytes of normal individuals and breast cancer patients
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H. Mozdarani   , S. Mozdarani , E. Samei , S. Mozdarani , F. Pakniat , H. Nosrati |
| Department of Medical Genetics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran , mozdarani@modares.ac.ir |
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Abstract: (42 Views) |
Background: The use of radioprotectors to ameliorate the deleterious effects of radiation could be an option to reduce normal tissue radiotoxicity. In this study, melatonin as an efficient naturally occurring antioxidant was used to explore its modulating effects on radiation induced cytogenetic damages at G0 and G2-lymphocytes of control and breast cancer (BC) patients. Materials and Methods: Whole blood samples were collected from 20 BC patients, and also 10 healthy individuals. Lymphocyte culture was initiated, irradiation was applied in G0-lymphocytes 1 hour before culture initiation using a 6 MV linear accelerator at dose of 3Gy and 4 hours before harvesting for G2-lymphocytes at a dose of 1Gy in the presence or absence of melatonin (800 µg/ml). Cytogenetic damages were assessed using cytochalasin-B blocked micronucleus (CBMN) assay and chromosomal aberrations were analyzed using G2-assay according to standard methods. Data were statistically analyzed and P-value <0.05 was considered as significant difference. Results: Results obtained for G0-irradiated lymphocytes in the presence of melatonin, showed a profound reduction in the frequency of CBMN in both lymphocytes of normal control and BC patients compared to radiation alone (p<0.05). Conversely, a significant increase in the frequency of radiation induced chromosomal aberrations was observed in both groups (p<0.05). Conclusion: Apparently melatonin exerts its modifying effect on radiation induced cytogenetic damages in a cell-cycle dependent manner. It acts as a radioprotector when lymphocytes have been irradiated in G0-phase of the cell cycle. Conversely it acts as radiosensitizer when used for lymphocytes exposed at G2-phase of the cell cycle. |
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| Keywords: Breast cancer, lymphocytes, antioxidants, ionizing radiation, radioprotector, radiosensitizer, cell cycle. |
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Full-Text [PDF 1019 kb]
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Type of Study: Original Research |
Subject:
Radiation Biology
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