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L. Schlichting, O. Strauss, O. Zeitz; Influence of Hydroxyl Radicals on the Ca2+–Metabolism of the Retinal Pigment Epithelium . Invest. Ophthalmol. Vis. Sci. 2005;46(13):3040.
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© ARVO (1962-2015); The Authors (2016-present)
An increased oxidative exposure of the retinal pigment epithelium (RPE) is hypothesized to play an important role in the genesis of age–related macular degeneration (AMD). Oxidative cell damage might be mediated by a disturbance of the Ca2+–homeostasis, subsequently leading to functional changes and apoptosis. In the present study, intracellular Ca2+–concentration is studied before and after exposing cultured RPE cells to oxidative stress.
All experiments were performed using the human RPE cell line ARPE–19. The intracellular Ca2+–content was determined by implementing the Fura–2 method. The ratio between the fluorescence intensities at 340 and 380nm is correlated to the Ca2+–concentration. The cells were incubated for 4 minutes with hydroxyl radicals that were created via the Fenton reaction using H2O2 and Fe3+ at different concentrations. Intracellular Ca2+–level was continuously tracked for up to 60 minutes after radical exposure.
Immediately after the onset of radical exposure the ARPE–19 cells showed a steep transient Ca2+–increase. The amplitude of this calcium–increase is dependent of the concentration of radicals used (table 1).
Oxidative exposure of cultured RPE cells leads to an intracellular Ca2+ overload. Changes in intracellular Ca2+–levels could lead to various cellular dysfunctions. This includes altered phagocytosis activity as well as changes in gene expression pattern and apoptosis, which should be investigated in future studies.
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