1999 Fiscal Year Final Research Report Summary
Project for development of in vivo rat model internal 131-iodine exposure in thyroid grand
| Project/Area Number |
09558072
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 展開研究 |
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| Research Field |
環境影響評価(含放射線生物学)
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| Research Institution | Nagasaki University School of Medicine |
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Principal Investigator |
YAMASHITA Shunichi Nagasaki University School of Medicine, Professor, 医学部, 教授 (30200679)
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| Co-Investigator(Kenkyū-buntansha) |
ITO Masahiro Nagasaki University School of Medicine, Subprofessor, 医学部, 助教授 (30184691)
SEKINE Ichiro Nagasaki University School of Medicine, Professor, 医学部, 教授 (60039922)
NAMBA Hiroyuki Nagasaki University School of Medicine, Subprofessor, 医学部, 助教授 (80237635)
MATSUYAMA Toshifumi Nagasaki University School of Medicine, Professor, 医学部, 教授 (30165922)
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| Project Period (FY) |
1997 – 1999
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| Keywords | Thyroid tumor / Radiation / Iodine-131 / Animal Model |
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| Research Abstract |
After Chernobyl disaster at 1986, the number of childhood thyroid cancer increased there. We were joining the Chernobyl Sasakawa Health and Medical Cooperation Project form 1991 to 1996. We screened more than 13000 children during 5 years. The incidence of childhood thyroid cancer is 100 times higher than Japan. Unfortunately, we did not have the data about the direct thyroid dosimetory of these patients at the time of the accident. The direct relationship between radiation and thyroid cancer is still uncertain. On the other hand, previous reports showed no increase of thyroid cancer among patients who were diagnosed or treated using Iodine-131. To elucidate whether radio-iodine intake cause thyroid cancer, we have tried to make animal model that is internally exposed by Iodine-131. Iodine-131(0, 0.2, 0.6, 1Mbq) was peritoneally injected to rats that previously took low iodine diets (n=10/each group). One, two, six or twelve months after radiation exposure, rats were sacrificed and analyzed pathophigiologically. We observed no increase of thyroid tumor among exposed rats. The result does not lead to any concrete conclusions because the number of examined rats is not good enough to statistically analyze. Furthermore, we speculate that rat spicies and their ages relate to sensitivity to cause thyroid tumors following radiation exposure. In future, we win further examine to answer the relationship between thyroid cancer and Iodine-131 exposure.
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