FIG. 3.
C-peptide inhibits high glucose (HG)–induced ROS generation, mitochondrial fission, and ∆Ψm collapse. HUVECs were incubated with HG for 48 h in the presence of the indicated concentrations (A) or 1 nmol/L (B–F) of C-peptide (CP) or heat-inactivated C-peptide (HI-CP). ROS generation, mitochondrial fission, expression of Drp-1 and Fis-1, and ∆Ψm were determined as described in research design and methods. A: C-peptide inhibited HG-induced generation of intracellular and mitochondrial ROS in a dose-dependent manner. *P < 0.05, **P < 0.01, ***P < 0.001 compared with HG. B: C-peptide inhibited HG-induced mitochondrial fission. C–E: C-peptide inhibited HG-induced expression of Drp-1 (D) and Fis-1 (E). C: Western blot analysis of Drp-1 and Fis-1 expression. Expression levels were normalized to β-actin. F: C-peptide inhibited HG-induced ∆Ψm collapse. However, HI-CP had no inhibitory effect on HG-induced generation of intracellular and mitochondrial ROS (A), mitochondrial fission (B), and ∆Ψm collapse (F). *P < 0.05, **P < 0.01, ***P < 0.001. Data are expressed as mean ± SD of three independent experiments. Ctrl, control.