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Two spectral types of retinal light damage occur in albino as well as in pigmented rat: no essential role for melanin.

Abstract

Earlier we showed that two spectral types of retinal damage occur in the pigmented rat. In the present study we investigated whether the same is true for albino rats. When investigating this issue we implicitly investigated the role of melanin in both damage types. An albinotic (Wistar) and a pigmented (Long Evans) strain of rats were used. Under anesthesia, a small part of the retina was irradiated at either 380 nm or at 470 nm. Three days later, the retina was analysed by funduscopy and prepared for light microscopy. Funduscopy showed no signs of damage in the albinotic retina. In the pigmented retina a decoloration of the fundus was noticed after irradiations starting from retinal doses of 0.6+/-0.1 J cm-2 at 380 nm, and from 489+/-71 J cm-2 at 470 nm. By light microscopy, retinal damage was found in the albino retina. The histologic manifestations at 380 nm differed from those at 470 nm. Irradiation at 380 nm at a dose of 0. 5-0.9 J cm-2 damaged a few scattered photoreceptor cells. At doses of 1.2-1.6 J cm-2 all rods were damaged, while the other retinal layers showed no changes. These findings were similar to those found at 380 nm in the pigmented rat. At 470 nm, damage was found most prominently in the retinal pigment epithelium. These cells showed swelling and an increased number of dark inclusions. Threshold damage occurred at doses of 250-500 J cm-2. Again, the pathology in the pigmented rat was highly similar to that in the albino rat. The results show that both spectral damage types occur in albino as well as in pigmented retina. Therefore, melanin plays no crucial role in these light damage types.

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  • Authors+Show Affiliations

    ,

    Helmholtz Institute, Department of Ophthalmology, Utrecht University, P.O. Box 85500, Utrecht, GA, NL-3508, The Netherlands.

    Source

    Experimental eye research 66:2 1998 Feb pg 155-62

    MeSH

    Albinism, Ocular
    Animals
    Light
    Male
    Melanins
    Photoreceptor Cells
    Pigment Epithelium of Eye
    Rats
    Rats, Wistar
    Retina

    Pub Type(s)

    Journal Article
    Research Support, Non-U.S. Gov't

    Language

    eng

    PubMed ID

    9533842

    Citation

    Gorgels, T G., and D Van Norren. "Two Spectral Types of Retinal Light Damage Occur in Albino as Well as in Pigmented Rat: No Essential Role for Melanin." Experimental Eye Research, vol. 66, no. 2, 1998, pp. 155-62.
    Gorgels TG, Van Norren D. Two spectral types of retinal light damage occur in albino as well as in pigmented rat: no essential role for melanin. Exp Eye Res. 1998;66(2):155-62.
    Gorgels, T. G., & Van Norren, D. (1998). Two spectral types of retinal light damage occur in albino as well as in pigmented rat: no essential role for melanin. Experimental Eye Research, 66(2), pp. 155-62.
    Gorgels TG, Van Norren D. Two Spectral Types of Retinal Light Damage Occur in Albino as Well as in Pigmented Rat: No Essential Role for Melanin. Exp Eye Res. 1998;66(2):155-62. PubMed PMID: 9533842.
    * Article titles in AMA citation format should be in sentence-case
    TY - JOUR T1 - Two spectral types of retinal light damage occur in albino as well as in pigmented rat: no essential role for melanin. AU - Gorgels,T G, AU - Van Norren,D, PY - 1998/6/17/pubmed PY - 1998/6/17/medline PY - 1998/6/17/entrez SP - 155 EP - 62 JF - Experimental eye research JO - Exp. Eye Res. VL - 66 IS - 2 N2 - Earlier we showed that two spectral types of retinal damage occur in the pigmented rat. In the present study we investigated whether the same is true for albino rats. When investigating this issue we implicitly investigated the role of melanin in both damage types. An albinotic (Wistar) and a pigmented (Long Evans) strain of rats were used. Under anesthesia, a small part of the retina was irradiated at either 380 nm or at 470 nm. Three days later, the retina was analysed by funduscopy and prepared for light microscopy. Funduscopy showed no signs of damage in the albinotic retina. In the pigmented retina a decoloration of the fundus was noticed after irradiations starting from retinal doses of 0.6+/-0.1 J cm-2 at 380 nm, and from 489+/-71 J cm-2 at 470 nm. By light microscopy, retinal damage was found in the albino retina. The histologic manifestations at 380 nm differed from those at 470 nm. Irradiation at 380 nm at a dose of 0. 5-0.9 J cm-2 damaged a few scattered photoreceptor cells. At doses of 1.2-1.6 J cm-2 all rods were damaged, while the other retinal layers showed no changes. These findings were similar to those found at 380 nm in the pigmented rat. At 470 nm, damage was found most prominently in the retinal pigment epithelium. These cells showed swelling and an increased number of dark inclusions. Threshold damage occurred at doses of 250-500 J cm-2. Again, the pathology in the pigmented rat was highly similar to that in the albino rat. The results show that both spectral damage types occur in albino as well as in pigmented retina. Therefore, melanin plays no crucial role in these light damage types. SN - 0014-4835 UR - https://www.unboundmedicine.com/medline/citation/9533842/Two_spectral_types_of_retinal_light_damage_occur_in_albino_as_well_as_in_pigmented_rat:_no_essential_role_for_melanin_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0014-4835(97)90416-4 DB - PRIME DP - Unbound Medicine ER -