Abstract
Purpose: :
We have previously shown that mitochondrial damage in the RPE induced by endogenous reactive oxygen species has a strong association with the pathogenesis of AMD. In this study, we examine the effects of multiple effectors including rosiglitazone, resveratrol, 17-β-estradiol and mitotropic agents including delocalized lipophilic cations (DLCs) linked reagents such as MitoQ, MitoPBN, MitoE and MitoPeroxidase on RPE cell REDOX potential.
Methods: :
Confluent ARPE19 and primary RPE cells isolated from the maculas of normal and AMD donors were pretreated with varying concentrations of the mitochondrial protectors for 3 to 7 days and exposed to 200 µM H2O2 for 1 hour. Redox function and complex IV activity of these cells was assessed using the MTT and Rapid Microplate Assay for complex IV activity assays respectively. mtDNA damage was assayed by quantitative PCR. Mitochondrial mass were determined using MitoTracker green stain and confocal microscopy together with MetaMorph image analysis.
Results: :
Pre-treatment with rosiglitazone, resveratrol, 17-β-estradiol individually significantly protected mitochondria redox function and complex IV activity in RPE cells exposed to 200 µM H2O2 compared to control (p<0.05). These agents also significantly reduced the H2O2-induced mtDNA damage (p<0.05) with 17-β-estradiol reducing DNA damage by 20% compared to untreated control. In addition, rosiglitazone and resveratrol in combination exhibited synergistic mitochondrial protection against H2O2-induced damage. Mitotropic agents including, MitoQ, MitoPBN, MitoE and MitoPeroxidase also demonstrated strong mitochondrial protective effects by reducing the loss of redox function and reducing DNA damage in RPE cells exposed to H2O2. Interestingly, in some treatments the reagents were able to increase overall mitochondrial mass in RPE cells.
Conclusions: :
Our studies predict that mitochondrial function can be protected or rescued in RPE cells by pharmacological intervention and that this will reduce RPE dysfunction associated with aging and disease. This may offer alternative possibilities for the treatment of AMD.
Keywords: antioxidants • retinal pigment epithelium • mitochondria