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R. Rojas, A. Z. Chuang, C. K. Mitchell, L. Carter-Dawson; Albumin Protects RGC-5 Cells From Oxidative Insults. Invest. Ophthalmol. Vis. Sci. 2008;49(13):5929. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
Oxidative damage contributes to the injury and death of retinal ganglion cells in patients with glaucoma and in experimental animal models of the disease. We previously observed that albumin was elevated 2.4 fold in the retina and 10-25 fold in the vitreous of monkeys with experimental glaucoma. The purpose of the current study is to determine whether a 10-25 fold increase in albumin is detrimental or protective for neurons exposed to oxidative insults.
An immortalized cell line derived from rat retinal ganglion cells, RGC-5, (gift from N. Agarwal) was used to test the impact of albumin on cell viability (MTT assay) in normoxic and oxidizing conditions. RGC-5 cell viability was tested after exposure to 0, 0.01, 0.1 or 0.25g/dL albumin in DPBS in normoxic conditions or in oxidative conditions derived either extracellularly by treatment with 2mM SIN-1 or intracellularly by treatment with 25mM glutamate. Cell viability was compared using two-way ANOVA. Differences between treatment conditions were considered significant at the 5% level (post-hoc multiple comparisons).
In normoxic conditions, albumin did not alter RGC-5 cell viability at any of the concentrations tested compared to that without albumin. Exposure of RGC-5 cells to 2mM SIN-1, in the absence of albumin, significantly reduced viability to 41% of that observed in normoxic control. Cell viability was significantly improved with the addition of albumin at 0.01g/dL by 80% compared to that of SIN-1 without albumin. A 10-fold (0.1g/dL) increase in albumin significantly enhanced viability (107%), but no further enhancement of viability occurred with 0.25g/dL of albumin. Treatment of RGC-5 cells with 25mM glutamate, in the absence of albumin, reduced cell viability to 42% of that observed in normoxic controls. Adding albumin at 0.01g/dL simultaneously with glutamate significantly improved cell viability by 47% compared to that of glutamate without albumin. A 10-fold increase in albumin, 0.1g/dL, significantly enhanced viability (116%), however, no further enhancement of viability occurred with 0.25g/dL of albumin.
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