1998 Fiscal Year Final Research Report Summary
Cerebral cytochrome c oxidase and hemoglobin oxygenation by full spectrum near infrared spectroscopy and phosphocreatine / Pi by ィイD131ィエD1P-magnetic resonance spectroscopy during insulin-induced hypoglycemia in newborn piglet
| Project/Area Number |
09671193
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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 |
Embryonic/Neonatal medicine
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| Research Institution | Kagawa Medical University |
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Principal Investigator |
ONISHI Shoji Kagawa Medical School Professor, 医学部, 教授 (40080014)
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| Co-Investigator(Kenkyū-buntansha) |
IMAI Tadashi Kagawa Medical School Instructor, 医学部, 助手 (60176477)
ISOBE Kenichi Kagawa Medical School Assistant Professor, 医学部・附属病院, 講師 (00159815)
ITOH Susumu Kagawa Medical School Assistant Professor, 医学部, 講師 (80145052)
KAWADA Kou Kagawa Medical School Instructor, 医学部・附属病院, 助手 (40284369)
KUSAKA Takashi Kagawa Medical School Instructor, 医学部・附属病院, 助手 (50274288)
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| Project Period (FY) |
1997 – 1998
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| Keywords | redox state of cytochrome c oxidase / phosphocreatine / inorganic phosphate / insulin-indeced hypoglycemia / newborn piglet brain / ィイD131ィエD1P-magnetic resonance spectroscopy / cerebral oxygenation / full-spectrum near infrared spectroscopy / piglet |
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| Research Abstract |
Glucose is the major substrate for the cerebral energy metabolism, and brain damage can result when the glucose supply is severely restricted. The purpose of the present study was to investigate the relation between the redox state of cytochrome c oxidase and phosphocreatine/inorganic phosphate (PCr/Pi) during insulin-induced hypoglycemia in the newborn piglet brain. We simultaneously measured the cerebral energy metabolism by ィイD131ィエD1P-Resonance Spectroscopy (ィイD131ィエD1P-MRS) and the cerebral oxygenation by full-spectrum near infrared spectroscopy (fsNIRS). Five newborn piglets were studied ; within 24 hours after birth. Hypoglycemia was induced by bolus injection of rapid insulin.
Total Hb rose slightly, under insulin load, when there was a gradual decrease in blood glucose. While blood glucose remained above 10 mg/dl, the oxidized form of cytochrome c oxidase remained nearly unchanged or rose slightly. When blood glucose was reduced to a level lower than 10 mg/dl, the oxidized form of cytochrome c oxidase fell rapidly.
Moreover, PCr/Pi remained above 1.2, while the oxidized form of cytochrome c oxidase was almost constant between 55-70%. However, below 1.2, the oxidized form of cytochrome c oxidase decreased linearly with PCr/Pi. Furthermore, the oxidized form of cytochrome c oxidase during hypoglycemic loading was only slightly lower than the oxidized form of cytochrome c oxidase that had been reduced during hypoxic loading.
The administration of glucose caused the oxidized form of cytochrome c oxidase to recover to the prevalue in about 30 mm, whereas the recovery of PCr/Pi was slower.
The above results serve to explain that prolonged severe hypoglycemia causes the depletion of ATP in brain cells and in turn an insufficient amount of energy for the maintenance of microstructures within the cells, thus producing a strain on the subunits of cytochrome c oxidase. However, further detailed study is necessary.
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[Publications] T Kusaka, K Isobe, K Kawada, Y Ohtaki, S Itoh, K Hirao, S Onishi: "Photon Propagation in Tissues III Benaron DA, Benaron DA, Chance B, Ferrari M eds, SPIE- The International Society for Optical Engineering"Proceedings postnatal changes in the cerebral oxygenation on normal and asphyxiated neonates. PROGRESS IN BIOMEDICAL OPTICS EUROPTO SERIES Vol.3194. 92-102 (1998)
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