FIG. 3.
Mitochondrial respiratory chain activity is impaired in freshly isolated mitochondria from lumbar DRG of 22 weeks of STZ-diabetic rats. After measurement of coupled respiration, the ATP synthase specific inhibitor, oligomycin, was added to prevent reverse pumping of protons by the ATPase, and then the uncoupled rate of mitochondrial respiration was generated by adding the uncoupling agent FCCP. Basal respiration (A), pyruvate + malate + ADP (coupled oxidative phosphorylation) (B), FCCP (uncoupled respiration) (C), and the respiration rate with Asc + TMPD (complex IV) (D) were measured in age-matched controls (Ctrl), STZ-diabetic rats (Db), and STZ-diabetic rats with insulin implant (Db + Ins) after 22 weeks of diabetes. Values are means ± SD, n = 6. *P < 0.05 vs. other groups; **P < 0.05 vs. Db + Ins (one-way ANOVA with Tukey's post hoc comparison). Treatment of the mitochondrial preparation with the uncoupler FCCP induced a four- to sixfold elevation in the rate of oxygen consumption over the basal rate confirming that the mitochondrial preparations were intact and of high quality in all groups.