DNA synthesis in irradiated intestinal epithelium |
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| Affiliation: | 1. Brown University, Providence, R.I., U.S.A.;2. Brookhaven National Laboratory, Upton, New York, U.S.A.;1. Department of Physics, University of the Punjab, Quaid-e-Azam Campus, 54590, Lahore, Pakistan;2. Centre for High Energy Physics, Punjab University, Quaid-e-Azam Campus, 54590, Lahore, Pakistan;3. Centre for Advanced Studies in Physics, GC University, Lahore, 54000, Pakistan;4. College of Engineering, Department of Chemical Engineering, King Saud University, Riyadh, Saudi Arabia;1. Graduate School of System Design, Tokyo Metropolitan University, Tokyo, Japan;2. Research Institute for Science and Technology, Kogakuin University, Tokyo, Japan;1. Graduate School of Engineering, Chubu University, Aichi 487-8501, Japan;2. College of Life and Health Sciences, Chubu University, Aichi 487-8501, Japan;3. Graduate School of Science and Technology, Tokushima University, Tokushima 770-8501, Japan;4. Institute of Engineering, Tokyo University of Agriculture and Technology, Tokyo 184-8588, Japan;5. The Institute of Scientific and Industrial Research, Osaka University, Osaka 567-0047, Japan;6. Faculty of Engineering, Hokkaido University, Hokkaido, 060-8628, Japan;7. Nisshin Electric Co., Ltd., Kyoto 615-8686, Japan;8. Toyota Technological Institute, Aichi 468-8511, Japan;1. Fundamental Science on Nuclear Safety and Simulation Technology Laboratory, Harbin Engineering University, Harbin 150001, China;2. Nigeria Atomic Energy Commission, Abuja, Nigeria;1. Institute and Department of Physiology, School of Medicine, National Yang-Ming University, Taipei 11221, Taiwan, ROC;2. Department of Medicine, School of Medicine, National Yang-Ming University, Taipei 11221, Taiwan, ROC;3. Department of Healthcare Administration, Asia University, Taichung 41354, Taiwan, ROC;4. Graduate Institute of Basic Medical Science, College of Medicine, China Medical University, Taichung 40402, Taiwan, ROC;5. Division of Allergy-Immunology-Rheumatology, Taipei Veterans General Hospital, Taipei 11217, Taiwan, ROC;1. Advanced Molecular Imaging Center, Faculty of Medicine, Oita University, 1-1 Idaigaoka, Hasama-machi, Yufu City, Oita 879-5593, Japan;2. Department of Radiology, Faculty of Medicine, Oita University, 1-1 Idaigaoka, Hasama-machi, Yufu City, Oita 879-5593, Japan |
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| Abstract: | - 1.1. DNA synthesis in the intestinal epithelium of X-irradiated mice was studied by means of autoradiography following labeling with tritiated thymidine. Radiation doses used varied from 200 to 3000 rads whole-body irradiation. The label was administered once or 5 times, at times ranging from one day before to 3 days after irradiation. The time from irradiation to sacrifice varied from 0 to 3 days.
- 2.2. Irradiation results in reduction of thymidine incorporation. The rapidity of development and the ultimate severity of this effect increase with dose.
- 3.3. An analysis of possible mechanisms indicates that the initial phase of the effect observed is a block of DNA synthesis in cells in the DNA synthesis phase.
- 4.4. The fate of cells irradiated while in DNA synthesis phase was studied. Some of them die, the majority mature precociously and emigrate into the region occupied by mature cells, and some remain in the zone of proliferation.
- 5.5. After moderate to heavy doses, DNA synthesis is resumed long before cell division. In heavily irradiated mice, the remaining crypt cells go through one to two cycles of DNA synthesis not followed by division.
- 6.6. The migration of mature cells along the villi is not markedly affected by irradiation. Emptying of the crypts occurs in heavily irradiated animals chiefly on the first and third day after irradiation, at times when there is no or little DNA synthesis.
- 7.7. These observations, combined with the results of previous studies, shed some light on the mechanisms which control cell movements, particularly the transitions from crypts to villi.
- 8.8. Qualitative and quantitative changes in the population of mature cells on the villi reflect the lack of cell proliferation and changes of cell retention in the crypts.
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