| Project/Area Number |
07671910
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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 |
Ophthalmology
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| Research Institution | Hamamatsu University School of Medicine |
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Principal Investigator |
WATANABE Ikuo Dept.Ophthalmol., Hamamatsu University School of Medicine Professor, 医学部, 教授 (50107827)
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| Co-Investigator(Kenkyū-buntansha) |
MASUDA Koji Dept.Ophthalmol., Hamamatsu University School of Medicine Assistant, 医学部, 助手 (10273195)
AONUMA Hidemi Dept.Ophthalmol., Hamamatsu University School of Medicine Assistant, 医学部, 助手 (60202488)
KATO Masaru Dept.Ophthalmol., Hamamatsu University of School of Medicine Lecturer, 医学部, 講師 (60161121)
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| Project Period (FY) |
1995 – 1996
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| Project Status |
Completed (Fiscal Year 1996)
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| Budget Amount *help |
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1996: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 1995: ¥1,100,000 (Direct Cost: ¥1,100,000)
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| Keywords | photochemical retinal damage / blue light hazard / ERG / electron microscopy / apoptosis / rat / rabbit / EOG / 光化学反応 / 網膜電図(ERG) / 眼電図(EOG) / 電子顕微鏡所見 / apoptosis / 網膜電図 / 防御因子 / アスコルビン酸 / Midkine / vitamin E |
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| Research Abstract |
We investigated the photochemical damage in the rat after the exposure to the light of fluorescenht tube (1.2*10^4 mW/m^2). Over 12 hours exposure and after 14 days dark recovery we found a significant decrease in ERG a- and b-waves amplitudes and a decrease of outer unclear layr thickness at upper part of the retina.
In the rat, peak of the rod cell death appeared 2-3 days after the light exposure and in the cone it appeared 2-3 weeks later. At the early stage of the photochemical retinal damage, numerous apoptosis were observed in the inner layr of the retina, but cell deaths in inner nuclear layr and ganglion cell layr was necrosis.
Systemic administration of over 0.5 mg/g body weight of ascorbic acid and intravitreous injection of 1ug/ul of Mikdine (heparin binding cell growth factor) and basic fibroblast growth factor (bFGF) showed significant preventative effects against the photochemical retinal damage.
alpha-tocopherol did not show any preventative effect in electrophysiological s
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tudies. Both a-tocopherol deficient and supplemented rats showed the same decrease in the amplitudes of ERG and in the outer nuclear layr thickness, even the content of a-tocopherol in the retina differed 80 times between two groups. Electron microscopic study revealed more derangement of the visual cell outer segment disks in the deficiency rats than in supplemented rats under the short term light exposure, but prolonged light exposure did not show any difference between these two groups. After 24 hours light exposure, pyknois of the visual cell nucleus in the supplemented group was 60% and 90% in the deficient group. This conderisation of the nucleus is considered as apoptosis.
In the rats, after over 30 minutes exposure to the blue light of 4.0*10^4 mW/m^2, ERGs a- and b-waves and oscillatory potentials showed significant decrease in the amplitudes. They showed dark recovery up to 14 days after the light exposure.
The rabbits, after 7 days light exposure at 7000 lux, showed 22% decrease in the EOG amplitudeat 30 minute of light adaptation. Less
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