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Evidence against melanin as the mediator of retinal phototoxicity by short-wavelength light.

Abstract

Albino and pigmented (black-hooded) rats of the Sprague-Dawley and Long Evans strains, respectively, were compared in terms of their susceptibility to retinal damage by ultraviolet-A light. Anesthetized animals were exposed to ultraviolet-A light (lambda max = 360 nm) for 4 hr and retinal damage was assessed 1 week later by electroretinographic analysis and measurement of outer nuclear layer thickness. Albino and pigmented animals showed approximately the same severity of ultraviolet-A retinal damage as a function of exposure irradiance. Furthermore, both pigmentation strains showed swelling and vesiculation of rod inner segment mitochondria as an early manifestation of damage. An abbreviated study on a congenic rat strain (F344-c/+) of albino and pigmented littermates again demonstrated an equal susceptibility to ultraviolet-A phototoxicity for both pigmentation phenotypes. These findings provide evidence that melanin is not the mediator of short-wavelength phototoxicity to the retina, since damage readily occurred in albino animals completely lacking this chromophore.

Authors+Show Affiliations

,

Cullen Eye Institute, Baylor College of Medicine, Houston, TX 77030.

Source

Experimental eye research 54:1 1992 Jan pg 55-62

MeSH

Albinism, Ocular
Animals
Electroretinography
Female
Melanins
Microscopy, Electron
Photoreceptor Cells
Pigment Epithelium of Eye
Radiation Injuries, Experimental
Rats
Rats, Inbred Strains
Retina
Ultraviolet Rays

Pub Type(s)

Comparative Study
Journal Article
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

1541341

Citation

Rapp, L M., and S C. Smith. "Evidence Against Melanin as the Mediator of Retinal Phototoxicity By Short-wavelength Light." Experimental Eye Research, vol. 54, no. 1, 1992, pp. 55-62.
Rapp LM, Smith SC. Evidence against melanin as the mediator of retinal phototoxicity by short-wavelength light. Exp Eye Res. 1992;54(1):55-62.
Rapp, L. M., & Smith, S. C. (1992). Evidence against melanin as the mediator of retinal phototoxicity by short-wavelength light. Experimental Eye Research, 54(1), pp. 55-62.
Rapp LM, Smith SC. Evidence Against Melanin as the Mediator of Retinal Phototoxicity By Short-wavelength Light. Exp Eye Res. 1992;54(1):55-62. PubMed PMID: 1541341.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Evidence against melanin as the mediator of retinal phototoxicity by short-wavelength light. AU - Rapp,L M, AU - Smith,S C, PY - 1992/1/1/pubmed PY - 1992/1/1/medline PY - 1992/1/1/entrez SP - 55 EP - 62 JF - Experimental eye research JO - Exp. Eye Res. VL - 54 IS - 1 N2 - Albino and pigmented (black-hooded) rats of the Sprague-Dawley and Long Evans strains, respectively, were compared in terms of their susceptibility to retinal damage by ultraviolet-A light. Anesthetized animals were exposed to ultraviolet-A light (lambda max = 360 nm) for 4 hr and retinal damage was assessed 1 week later by electroretinographic analysis and measurement of outer nuclear layer thickness. Albino and pigmented animals showed approximately the same severity of ultraviolet-A retinal damage as a function of exposure irradiance. Furthermore, both pigmentation strains showed swelling and vesiculation of rod inner segment mitochondria as an early manifestation of damage. An abbreviated study on a congenic rat strain (F344-c/+) of albino and pigmented littermates again demonstrated an equal susceptibility to ultraviolet-A phototoxicity for both pigmentation phenotypes. These findings provide evidence that melanin is not the mediator of short-wavelength phototoxicity to the retina, since damage readily occurred in albino animals completely lacking this chromophore. SN - 0014-4835 UR - https://www.unboundmedicine.com/medline/citation/1541341/Evidence_against_melanin_as_the_mediator_of_retinal_phototoxicity_by_short_wavelength_light_ DB - PRIME DP - Unbound Medicine ER -