Abstract

This work aims at investigating the protective effects of the mitochondria-targeted peptide SS31, on mitochondria function, preventing human retinal pigment epithelial cell-19 (ARPE-19) cell apoptosis. The ARPE-19 cells were subjected to 24 h of intervention with H2O2 of various concentrations (0, 100, 150, 200, 250, 300, and 500 μmol/L). Various concentrations of SS31 (10 nM, 100 nM, and 1 μmol/L) pretreated the cells for 2 h. The MTT assay determined cell viability. ARPE-19 cell apoptosis was observed by 4,6-diamidino-2-phenylindole (DAPI) staining under fluorescence microscope and detected by Annexin-V/PI staining under flow cytometry. The measurement of reactive oxygen species (ROS) release level used MitoSOX Red (a mitochondrial superoxide indicator) and the probe 2-7dichlorofluorescin diacetate (DCFH-DA). And with the use of a JC-1 probe, the mitochondrial membrane potential (MMP; ) was analyzed. Reverse transcription polymerase chain reaction (RT-PCR) and real-time PCR were responsible for measuring the levels of apoptosis related genes (Bcl-2, Bax, and Caspase-3). The cell viability increased significantly with SS31 pretreated (). In the group, the fluorescence of the cell nuclei with DAPI staining was weaker than H2O2 along group accordance with the decreased ratio of apoptotic cells (). The ROS generation decreased in SS31 pretreated group, with the increased . The RT-PCR result showed decreased Bax gene and Caspase-3 gene expression with SS31 pretreatment, while increased antiapoptotic gene Bcl-2 (). We provide evidence that SS31 promotes resilience of RPE cells to oxidative stress by stabilizing mitochondrial function.