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

Figure 6

NAC protects against H₂O₂-induced mitochondrial oxidative phosphorylation impairment. RPE cells were treated with H₂O₂ (500 μM) for 24 hours with or without NAC (500 μM) pretreatment for 2 hours. Relative oxygen consumption rate (OCR) levels in No AMD () and AMD () cells were normalized to no treatment for each donor. Maximal respiration (MR) and spare respiratory capacity (SRC) were calculated for (a) No AMD and (b) AMD cells. (c) Relative OCR after NAC treatment was compared between No AMD (NA) and AMD (A) cells. (d) NAC protection was calculated as NAC+H₂O₂ (NAC+ox) relative to H₂O₂ (ox) alone. One-sample -tests were used to compare NAC treatment or H₂O₂ alone to no treatment (set to 1) in No AMD and AMD groups (a, b). Unpaired -tests were used to compare H₂O₂ treatment to NAC+H₂O₂ treatment in (a, b). Unpaired -tests were used to compare responses of No AMD to AMD in (c, d). Data are the mean (±SEM). ^† denotes significance from the no treatment control, and denotes significance between conditions. or ^† and ^†† were statistically significant.

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