| Project/Area Number |
08670409
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Hygiene
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| Research Institution | The Institute for Science of Labour |
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Principal Investigator |
KAWAMI Masaki The Institute of Science of Labour, 労働環境保健研究部, 主任研究員 (80153005)
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| Co-Investigator(Kenkyū-buntansha) |
EBIHARA Isamu The Institute of Science of Labour, 労働環境保健研究部, 主任研究員 (80124311)
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| Project Period (FY) |
1996 – 1998
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| Project Status |
Completed (Fiscal Year 1998)
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| Budget Amount *help |
¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 1998: ¥100,000 (Direct Cost: ¥100,000)
Fiscal Year 1997: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 1996: ¥600,000 (Direct Cost: ¥600,000)
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| Keywords | chlorpyrifos / dichlofenthion / immunotoxicty / thymus atrophy / apoptosis / thymocytes subpopulation / organophosphorus insecticide / thymus microenvironment / ジクロフェンチオン / 動物実験 |
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| Research Abstract |
Chlorpyrifos (CP) and dichlofenthion (ECP) are widely used as organophosphorus insecticide. The purpose of this study is to examine the immunotoxicological effects of CP and ECP on the thymus of rat as target organ of immunotoxicty.
The thymus of the F344 rat was studied in vitro and in vivo. For studies assessing the in vitro effect of si multaneous exposure of thymocytes to CP and ECP, rat thymocytes cultures were harvested and processed for flow cytometric analysis of DNA content. For the in vivo effect of CP and ECP, male F344 rats were exposed to CP (10, 20, 40mg/kg) and ECP (20, 40, 80mg/kg) by gavage, daily for 7 days.
We observed that rat thymocytes cultures exposed to CP and ECP exhibited dose-dependent induction of apoptosis as a discrete subpopulation containing less than the diploid complement of DNA when analyzed by flow cytometry. On the in vivo effect of CP and ECP, we found that CP and ECP treatment induced significant thymic atrophy on highest dose. Determination of the thymocytes subpopulation showed a significant reduction of percentage of CD4+CD8+ cells as immature cells. Using a histochemical approach, on the thymus of ECP treatment. CD4+CD8+ cell in cortex were less frequently observed than vehicle control. The cortex of ECP-treated rat showed increased numbers of macrophages containing cell debris. These macrophages may correlate with subsequent removal of dead cell remnants by phagocytosis.
These results suggest that CP and ECP induced thymus atrophy and reduction of percentage of CD4+CD8+ cells as immature cells, which might associate with apoptosis.
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