1998 Fiscal Year Final Research Report Summary
Does DNA fragmentation in myocytes in infarct area really mean apoptosis?
| Project/Area Number |
09670708
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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 |
Circulatory organs internal medicine
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| Research Institution | Gifu University |
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Principal Investigator |
TAKEMURA Genzou Gifu University, Medicine, Assistant Professor, 医学部・附属病院, 助手 (40283311)
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| Co-Investigator(Kenkyū-buntansha) |
FUJIWARA Hisayoshi Gifu University, Medicine, Professor, 医学部, 教授 (80115930)
NODA Toshiyuki Gifu University, Medicine, Associate Professor, 医学部・附属病院, 講師 (00262759)
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| Project Period (FY) |
1997 – 1998
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| Keywords | apoptosis / DNA fragmentation / ultrastructure / cardiac myocyte / ischemia / reperfusion / myocardial infarction |
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| Research Abstract |
Thirty rabbits were divided into 5 groups (n=6 each) that were subjected to a sham operation or to 30-minute ischemia followed by 0-minute, 30-minute, 2-hour, or 4-hour reperfusion of a coronary artery. In the 2- and 4-hour reperfusion groups only, DNA electrophoresis showed a ladder pattern, and a light microscopic TUNEL finding was positive in the nuclei of myocytes localized in the infarcted area (6"+"2% and 11"+"3%, respectively). Electron microscopic TUNEL showed that nuclei with a significant accumulation of immunogold particles (indicating an electron microscopic TUNEL-positive result) were observed only in the infarcted myocytes with irreversibly oncotic ultrastructures that were found in the hearts of the 2- and 4-hour reperfusion groups (41 3% and 83 4%, respectively). Irreversibly oncotic myocytes (indicated by swelling, inhomogeneously clumped chromatin in nuclei, dense bodies in mitochondria, and/or ruptured plasma membranes) were also seen in the 0- and 30-minute reperfusion groups, which did not exhibit TUNEL-positive myocytes. There was no evidence of apoptotic ultrastructures in the myocytes.
DNA fragmentation occurs in the myocytes that had already shown irreversibly oncotic, but not apoptotic, ultrastructures with ischemia and/or reperfusion. Therefore, DNA fragmentation itself does not always mean apoptosis, and so-called apoptotic infarcted myocytes may belong to a category of cell death other than apoptosis.
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Research Products
(10 results)
