Products of Docosahexaenoate Oxidation as Contributors to Photosensitising Properties of Retinal Lipofuscin.
Int J Mol Sci
; 22(7)2021 Mar 29.
Article
in En
| MEDLINE
| ID: mdl-33805370
ABSTRACT
Retinal lipofuscin which accumulates with age in the retinal pigment epithelium (RPE) is subjected to daily exposures to high fluxes of visible light and exhibits potent photosensitising properties; however, the molecules responsible for its photoreactivity remain unknown. Here, we demonstrate that autooxidation of docosahexaenoate (DHE) leads to the formation of products absorbing, in addition to UVB and UVA light, also visible light. The products of DHE oxidation exhibit potent photosensitising properties similar to photosensitising properties of lipofuscin, including generation of an excited triplet state with similar characteristics as the lipofuscin triplet state, and photosensitised formation of singlet oxygen and superoxide. The quantum yields of singlet oxygen and superoxide generation by oxidised DHE photoexcited with visible light are 2.4- and 3.6-fold higher, respectively, than for lipofuscin, which is consistent with the fact that lipofuscin contains some chromophores which do contribute to the absorption of light but not so much to its photosensitising properties. Importantly, the wavelength dependence of photooxidation induced by DHE oxidation products normalised to equal numbers of incident photons is also similar to that of lipofuscin-it steeply increases with decreasing wavelength. Altogether, our results demonstrate that products of DHE oxidation include potent photosensitiser(s) which are likely to contribute to lipofuscin photoreactivity.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Retina
/
Docosahexaenoic Acids
/
Light
/
Lipofuscin
Limits:
Humans
Language:
En
Journal:
Int J Mol Sci
Year:
2021
Document type:
Article
Affiliation country:
Reino Unido