Fig. 4

TPP-Niacin attenuated H₂O₂-induced mitochondrial membrane potential (△Ψm) losses and mitochondrial morphologies of ARPE-19 cells. After pretreatment with 25 and 50 μM TPP-Niacin for 2 h, ARPE-19 cells were incubated with or without 300 μM H₂O₂ for another 24 h. Quantification of red/green fluorescence intensities was determined by the JC-10 assay (a) and △Ψm was determined by TMRE staining. b CCCP (40 μM) and NAC (4 mM) were used as the positive and antioxidant controls, respectively. c Representative electron microscope images of the mitochondrial shape in the ARPE-19 cells treated without H₂O₂, with 300 μM H₂O₂ alone or with 300 μM H₂O₂ and 25 or 50 μM TPP-Niacin for 24 h. ## P < 0.01 versus control group and *P < 0.05, **P < 0.01, ***P < 0.001 versus the H₂O₂-treated group were considered statistically significantly different. Scale bar represents 50 μm. TMRE: tetramethylrhodamine ethyl ester, CCCP: carbonyl cyanide m-chlorophenyl hydrazine, NAC: N-acetyl-cysteine