| Project/Area Number |
17591784
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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 |
Otorhinolaryngology
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| Research Institution | Nagoya University |
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Principal Investigator |
TERANISHI Masaaki Nagoya University, Granduate School of Medicine, Associate Professor (20335037)
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| Co-Investigator(Kenkyū-buntansha) |
NAKASHIMA Tsutomu Nagoya University, Granduate School of Medicine, Professor (30180277)
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| Project Period (FY) |
2005 – 2007
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| Project Status |
Completed (Fiscal Year 2007)
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| Budget Amount *help |
¥3,680,000 (Direct Cost: ¥3,500,000、Indirect Cost: ¥180,000)
Fiscal Year 2007: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000)
Fiscal Year 2006: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 2005: ¥2,300,000 (Direct Cost: ¥2,300,000)
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| Keywords | inner ear / aging / nitric oxide(NO) / oxidative stress / nitric oxide (NO) / 蝸牛 / Akt / PKB / 加齡 |
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| Research Abstract |
Age-related hearing loss decreases quality of life of elderly people. Prevention and treatment of age-related hearing loss are important and urgent tasks. We investigated auditory function by auditory brain stem (ABR) responses, using C57BIJ8 mice as an experimental model of age-related hearing loss. We observed changes of nitric oxide and free-radical related substances in the inner ear using an immunohistcehemical method under a light microscope. ABE demonstrated that hearing levels of 7-8 month-old mice and 12 month-old mice were worse than those of 7 week-old mice. Hearing levels of 12 month-old mice were worse than those of 7-8 month-old mice. Expressions of inducible type NO synthase (NOS) and nitrotyrosine, a marker of peroxynitrite which is a strong radical, were enhanced in Corti organ, spiral ganglion cells and lateral wall of cochleae in 7-8 month-old mice, compared with 12 month-old mice. These results suggest that NO and oxidative stress is associated with cell damage and cell death of cochleae of aged mice. Hearing levels of mice with NOS gene deletion tend to be worse, as they grow old, compared with wild type, suggesting that NOS functions in a protective way for age-related heaving Ices. Active firm of Alit (phospho-Akt) influences NO production by activation of endothelial NOS (eNOS). Expression of Akt was observed in cochlea and vestibule in our experiments. This suggested that phospho-Akt is associated with survival signal in the inner eat.
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