1990 Fiscal Year Final Research Report Summary
Cytochemical Studies of Blood Retinal Barrier
| Project/Area Number |
63480394
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Ophthalmology
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| Research Institution | Kyoto University |
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Principal Investigator |
YASUBUTI Yikio Kyoto University Faculty of Medicine, Assistant Professor, 医学部, 講師 (70210276)
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| Co-Investigator(Kenkyū-buntansha) |
NISHIKAWA Masako Kyoto University Faculty of Medicine, Assistant Professor, 医学部, 助手 (50201687)
ISHIGUKA Hitoshi Kyoto University Faculty of Medicine, Assistant Professor, 医学部, 講師 (80135590)
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| Project Period (FY) |
1988 – 1990
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| Keywords | Peroxidase / Retinal pigment epithelium / Choriocapillaries / Bruch's membrane / Frozen thin-section / Cationized ferritin / Sialic acid / Charge barrier |
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| Research Abstract |
In order to study the characteristics of blood retinal barrier, various peroxidase molecules were utilized as cytochemical tracers. We observed the tracers penetrated through choriocapillaries and basal portion of Retinal Pigment Epithelial (RPE) cells under an electron microscope. Interestingly, smaller tracers with anionic charges did not penetrate much faster than larger tracers with cationic charges. The characteristics of invasion of such tracer proteins were modified according to their electrical charges.
The extracellular and intracellular distribution of anionic sites in RPE cells and choriocapillaries were examined by labeling ultra-thin frozen sections with cationized ferritin (CF). We demonstrated CF particles were distributed along the basal laminae of RPE cells and choriocapillaries. In RPE cell junctions, CF particles were evident on the surfaces of cell junctions except gap junctions. By labeling ultra-thin frozen sections with various lectin-ferritin, we showed these anionic site were mainly due to sialic acids.
Essner et al. have reported that Bruch's membrane has anionic sites and may serve as a charge barrier against the movement of anionic molecules from the choriocapillaries to RPE cells and the outer neural retina. Our findings showing that basal infoldings of RPE cells and the Bruch's membrane are denely labeled with cationized ferritin suggest that not only the Bruch's membrane but also the basal infoldings of the pigment epithelium have anionic sites and play a role as charge barrier.
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