Figure 5.

HG effects on mitochondrial electron transport chain (ETC) enzyme activity in rMC1. (a-b) Cytochrome c oxidase (CcO) activity was determined by increasing the amount of substrate cytochrome c in a polarographic method as described in Methods. CoO activity is defined as consumed O₂ [μM]/min/protein [mg]. Oxidative metabolism was increased after incubation in high glucose medium as was seen by an incremental increase of CcO activity at 24 h as well as at 3 and 5 day by ~12%. Shown are representative experiments (n = 3; standard deviation <4% at maximal turnover). (c) MTT Assay for rMC1 cell viability was measured in 48-well cultures at various time periods of hyperglycemia exposure. MTT activity was not significantly altered up to 2 days; however at day 3 to 5, there is a significant (P < 0.01, n = 6–8) increase versus LG (time 0 control).