Figure 5. miR-434-3p protects myotubes from caspase activation and loss of mitochondrial membrane potential. Myotubes were transfected with NS-mimetic, miR-434-3p mimetic, miR-434-3p antagomir or no transfection for 24 h followed by eight hours TPEN (100 μM) or Stps (1 μM) incubation. (A and B) Enzymatic activities of caspase-3, -8 and -9 in myotubes treated with TPEN (A) and Stsp (B) were determined by caspase specific fluorogenic substrates. (C) Untreated (control) or treated myotubes were stained with JC-1 and observed under TRITC (590 nm) and GFP (530 nm) filters. % Δψm index represents the ratio of red to green fluorescence. Each bar indicates mean ± SEM (n = 3). *, p < 0.05 vs. control; ϕ, p < 0.05 vs. NS-miR; δ, p < 0.05 vs. mimic.