FIG. 2.

Effects of local heart irradiation on mitochondrial membrane properties. Panel A: Mitochondrial membrane potential, as assessed by uptake of TMRM in isolated mitochondria, was significantly reduced at 6 h and 2 weeks after irradiation. Isolated mitochondria were incubated with TMRM, washed and the mitochondrial fluorescence was normalized to mitochondrial protein content. These normalized values for TMRM fluorescence of mitochondria isolated from irradiated hearts were calculated relative to the TMRM fluorescence of mitochondria isolated from sham-irradiated hearts. Panel B: Representative figure of the results of the swelling assay with mitochondria isolated at 2 weeks after irradiation. Swelling was assessed as a reduction in the OD540 nm of mitochondrial suspensions, relative to the OD540 nm of the same mitochondrial samples immediately before the start of the assay. Swelling was inhibited by CsA, indicating that swelling was due to mPTP opening. Swelling assays of other time points are shown in Supplementary Fig. S1 (http://dx.doi.org/10.1667/RR13452.1.S1). Average ± sem, n = 5–6. *P < 0.05 when compared to sham-irradiated control.