Figure 3

Verapamil enhances mitochondrial function in stressed MIN6 cells. To assess mitochondrial function, MIN6 cells were grown in a high-glucose medium and exposed to either diabetogenic stressors (STZ or a T1D-cytokine mix) with different timings of 50 µM verapamil treatment under pre-, post-, or co-treatment conditions. The cellular oxygen consumption rate (OCR) was measured by metabolic flux analysis following sequential treatment with 1 µM oligomycin, 2 µM FCCP, and 0.5 µM rotenone/antimycin A. (A–C) Verapamil alone: 50 μM verapamil (24 h) increased both basal (B) and maximal (C) OCR compared to the untreated controls. (D–F) Pre-treatment: cells pretreated with verapamil before stress exposure maintained higher basal respiration (E) and maximal respiration (F). (G–I) Post-treatment: verapamil administration after stress improved basal OCR (H) and maximal OCR (I). (J–L) Co-treatment: simultaneous verapamil + stressor treatment preserved basal respiration (K) and maximal respiration (L). The OCR data were normalized to the total protein extract measurements. The experimental groups were compared using two-way analysis of variance (ANOVA), with a statistically significant set at p-values < 0.05 considered statistically significant, and n = 4 per group. * p < 0.05, ** p < 0.01, *** p < 0.001, and **** p < 0.0001.