Figure 6.

Mitochondrial activity. A) Cultured 135-d fetal sheep cardiomyocytes (control and MEIS1 siRNA–transfected) were exposed to MitoO before they were fixed and stained with antibodies against α-Tub and cardiac troponin T (TnnT) and nuclei were stained with Hoechst 33258. MitoO accumulation is dependent upon membrane potential and is therefore an indicator of mitochondrial activity. All images were obtained by a maximum intensity projection of confocal z stacks. Scale bar, 10 μm. B) The same culture conditions were used on 96-well plates for luminescent ATP assessment. Data presented as means ± se; n = 5. *P < 0.05.