Small Interfering RNA Targeting Mitochondrial Calcium Uniporter Improves Cardiomyocyte Cell Viability in Hypoxia/Reoxygenation Injury by Reducing Calcium Overload

Figure 6

MCU silencing markedly reduced cardiomyocyte cell death in hypoxia/reoxygenation injury. (a and b) Representative dot-plot diagrams of flow cytometry viability/apoptosis analysis of siRNA-Neg and MCU-silenced cardiomyocytes in Nxy, after hypoxia and 1.5 h reoxygenation time. Viability and apoptosis were determined by PI and Annexin V PE-Cy7 conjugated staining, respectively. Q4 quadrant represents the viable cells, Q2 and Q3 represent the apoptotic cells, while Q1 and Q2 are the necrotic population. (c and d) Reoxygenation-time dependent cardiomyocyte viability and apoptosis at 0, 1.5, and 3 h reoxygenation, respectively. ; mean ± SEM; . Data is presented as percentage of Nxy conditions. (d) Apoptosis was ∼twofold and 1.5-fold increase in siRNA-Neg cardiomyocytes with respect to MCU-silenced cells at 1.5 and 3 h reoxygenation, respectively. Apoptosis is normalized to Nxy and expressed as fold change. , , versus siRNA-Neg cardiomyocytes, mean ± SEM, . (e) Time-dependent activation of caspases 3 and 7 and (f) caspase 9 during reoxygenation. , , versus siRNA-Neg cells, mean ± SEM, and ; Nxy, normoxic conditions.

(a)

(b)

(c)

(d)

(e)

(f)