N-Acetyl-L-cysteine Protects Human Retinal Pigment Epithelial Cells from Oxidative Damage: Implications for Age-Related Macular Degeneration

Figure 1

NAC protects against t-BHP-induced reactive oxygen species (ROS) production in RPE cells. RPE cells were treated with t-BHP (75 μM) for 3 hours with or without NAC (500 μM) pretreatment for 1 hour. The amount of ROS in (a) No AMD () cells and (b) AMD () cells was calculated relative to no treatment controls (dotted line). (c) ROS content after NAC treatment was compared between No AMD and AMD cells. (d) Percent increase (t-BHP—no treatment) of ROS in t-BHP-treated cells and (e) percent reduction (t-BHP—NAC+t-BHP) of ROS in NAC-pretreated cells were compared between No AMD and AMD donors. NA: No AMD; A: AMD. (f) mRNA expression of NOX family genes in No AMD () and AMD () cells was measured by real-time PCR. Results are fold change in expression relative to the average for No AMD samples (dotted line). (g) Expression of NOX family genes relative to housekeeping genes (dCt). One-sample -tests were used to compare NAC treatment or t-BHP alone to no treatment in No AMD and AMD groups (a, b). Unpaired -tests were used to compare t-BHP treatment to NAC + t-BHP treatment in (a, b). Unpaired -tests were used to compare responses of No AMD and AMD in (c–e). Unpaired -tests were used to compare basal expression of NOX genes in (f). One-way ANOVA with Tukey’s multiple comparison test was used to compare dCt values of NOX genes in (g). Data are the mean (±SEM). ^† denotes significance from the no treatment control, and denotes significance between conditions. and or ^††† were statistically significant. ^ǂ denotes significance in relative expression of NOX genes between No AMD and AMD groups. ^∧ and ^∨ denote significance between dCt values of NOX genes within No AMD or AMD groups.

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