Effects of LY294002 or siSIRT3 on the melatonin-mediated improvement in mitochondrial defects in high glucose-treated HT22 cells with SIR injury. (A) Representative images for mitochondrial membrane potential (MMP) assessed by flow cytometry. (B) Quantitative analysis of MMP. (C) Representative images for Cyt-cyto C expression detected by Western blot. (D) Quantitative analysis of the Cyt-cyto C protein levels. (E) Quantitative analysis of mitochondrial ATP content. (F) Representative images for NRF1 and TFAM expression detected by Western blot. (G–H) Quantitative analysis of the NRF1 and TFAM levels. Data were presented as the mean ± SEM (n = 6). ap < 0.05 vs. control group; bp < 0.05 vs. SIR+V group; cp < 0.05 vs. SIR+Mel group.