In vitro phototoxicity of rhodopsin photobleaching products in the retinal pigment epithelium (RPE).

In vitro phototoxicity of rhodopsin photobleaching products in the retinal pigment epithelium (RPE). Free Radic Res. 2019 May 02;:1-16 Authors: Olchawa M, Krzysztynska-Kuleta O, Duda M, Pawlak A, Pabisz P, Czuba-Pelech B, Sarna T Abstract Although the primary biological function of retinal photoreceptors is to absorb light and provide visual information, extensive exposure to intense light could increase the risk of phototoxic reactions mediated by products of rhodopsin bleaching that might accumulate in photoreceptor outer segments (POS). The phototoxicity of POS, isolated from bovine retinas, was examined in cultured retinal pigment epithelium cells (ARPE-19) containing phagocytised POS and in selected model systems by determining POS ability to photogenerate singlet oxygen, and photoinduce oxidation of cholesterol and serum albumin. Bleaching of rhodopsin-rich POS with green light resulted in the formation of retinoid products exhibiting distinct absorption spectra in the near-UV. Irradiation of POS-fed ARPE-19 cells with blue light reduced their survival in a dose-dependent manner with the effect being stronger for cells containing prebleached POS. The specific and non-specific phagocytic activity of ARPE-19 cells was inhibited by sub-lethal photic stress mediated by phagocytised POS. The oxidising ability of POS photobleaching products was demonstrated both in a model system consisting of serum albumin and in ARPE-19 cells. Dist...
Source: Free Radical Research - Category: Research Tags: Free Radic Res Source Type: research