| Project/Area Number |
01480532
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
放射線5生物学
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| Research Institution | University of Tokyo |
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Principal Investigator |
IJIRI Kenichi Tokyo Univ., Radioisotope Center, Associate Professor, アイソトープ総合センター, 助教授 (40111447)
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| Co-Investigator(Kenkyū-buntansha) |
NOGAWA Norio Tokyo Univ., Radioisotope Center, Technical staff, アイソトープ総合センター, 教務職員 (60208311)
TAO Kazuyuki Tokyo Univ., Radioisotope Center, Assistant, アイソトープ総合センター, 助手 (00211996)
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| Project Period (FY) |
1989 – 1991
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| Project Status |
Completed (Fiscal Year 1991)
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| Budget Amount *help |
¥3,400,000 (Direct Cost: ¥3,400,000)
Fiscal Year 1991: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 1990: ¥2,000,000 (Direct Cost: ¥2,000,000)
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| Keywords | Stem cells / Intestine / Crypt / Cell death / Apoptosis / Radiation / Radiosensitivity / Hypersensitive cells |
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| Research Abstract |
A technique for separating mouse small intestinal epithelial cells in vitro was established. The technique employed the mechanical and chemical separation methods together, and the validity of this technique was checked using the small intestine of the mice injected with I-125 deoxyuridine. Then, repeated injections of tritiated (H-3) thymidine were carried out from 18 hours till the 5th day after 10 Gy, and. at the points from half a month to 4 months later mice were sacrificed. Thirty minutes before the sacrifice, C-14 thymidine was injected into mice, their small intestines were excised, and cells were separated using the separation technique mentioned above. The radioactivity of H-3 and C-14 of each separated fractions were measured by the liquid scintillation counter. The fraction of the peak H-3 count and that of C-14 count slightly differed, showing that the (long-lived) stem cell population and rapidly-cycling cell population are the two different populations in the intestinal epithelium. Cell death (apoptosis) induced by a small dose of gamma rays were also examined in the intestinal crypts, of which stem cells were labelled as above and left for 0.5 to 6 months. The autoradiographs of the crypts cells were also made. The results clearly revealed that the stem cells and the target cells for apoptosis (hypersensitive cells) are different cell populations.
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