Research for mechanisms of induction of hepatic ischemic tolerance by ischemic preconditioning.
| Project/Area Number |
17590615
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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 |
Gastroenterology
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| Research Institution | The University of Tokyo |
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Principal Investigator |
TEJIMA Kazuaki The University of Tokyo, Faculty of Medicine, Medical Staff, 医学部附属病院, 医員 (30396733)
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| Co-Investigator(Kenkyū-buntansha) |
IKEDA Hitoshi The University of Tokyo, Faculty of Medicine, Associate Professor, 医学部附属病院, 助教授 (80202422)
TOMIYA Tomoaki The University of Tokyo, Faculty of Medicine, Research Associate, 医学部附属病院, 助手 (90227637)
YANASE Mikio The University of Tokyo, Faculty of Medicine, Research Associate, 医学部附属病院, 助手 (50334397)
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| Project Period (FY) |
2005 – 2006
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| Project Status |
Completed (Fiscal Year 2006)
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| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2006: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 2005: ¥2,700,000 (Direct Cost: ¥2,700,000)
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| Keywords | Ischemic preconditioning / Ischemia / reperfusion injury / Kupffer cells / NADPH oxidase / Oxygen radicals / Oxidative stress / Transplantation and regeneration |
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| Research Abstract |
Brief ischemia/reperfusion renders tissues resistant against subsequent prolonged ischemia/reperfusion(I/R), a phenomenon called ischemic preconditioning(IP). We have previously reported that pretreatment with sublethal dose of H_2O_2 mimicked the effect of IP. However, it is not cleared how the pretreatment with H_2O_2 promotes such hepatoprotection. Therefore, our aim was to investigate the mechanisms of hepatocyte preconditioning by H_2O_2 against warm I/R injury. In in vitro experiments, isolated rat hepatocytes were preincubated with 0-1 mM H_2O_2 for 10 min and then incubated at 37℃ for 5h under anoxia followed by reoxygenation. Cell viability was determined by propidium iodide fluorometry. In liver perfusion experiments, livers were perfused through portal vein with physiological buffer and then preconditioned by 10 min perfusion with 1 mM H_2O_2 containing buffer or by 10 min ischemia/10 min reperfusion(IP). Subsequently, livers were stored at 37℃ for 40 min and reperfused for
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1h in recirrculating system for determination of liver enzymes in the perfusate. Some rats were injected intravenously with GdCl_3 at 24h before experiments to deplete Kupffer cells, or perfused with NADPH oxidase inhibitor(DPI). For histological evaluation of oxygen radical formation in Kupffer cells, livers of other non-treated rats were perfused with the buffer containing 1 mM H_2O_2 for 10 min and perfused with nitro blue tetrazolium(NBT). Preincubation with 0-1 mM H_2O_2 did not improve hepatocyte viability compared to control. Preconditioning by perfusion with 1 mM H_2O_2, however, reduced warm I/R injury. Treatment with GdCl_3 or DPI reversed the effect of H_2O_2 preconditioning. Liver perfusion with NBT showed oxygen radical formation in Kupffer cells alter brief perfusion with 1 mM H_2O_2 Hepatoprotective effect of ischemic preconditioning was also reversed by DPI. Therefore, it was suggested that H_2O_2 preconditioning, as well as IP, promoted hepatoprotection against warm I/R injury via NADPH oxidase in Kupffer cells. Less
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Report
(3 results)
Research Products
(5 results)
