Cardioprotective effects of PKG activation by soluble GC activator, BAY 60-2770, in ischemia-reperfusion-injured rat hearts

Figures

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  Fig 1. BAY 60–2770 reduces myocardial infarction in a rat IR injury model. Seven days after reperfusion, the infarct area was visualized using TTC staining from IR-injured and BAY 60–2770 pre-treated hearts (A). Representative TTC images from Nor (n = 10), IR (n = 5), BAY (n = 6) (B). *p < 0.05 between IR and BAY groups. Echocardiographic analysis is shown as percent of EF (C), FS (D), and LVDD (mm, E). *p <0.05, **p <0.005 vs. IR.

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  Fig 2. BAY 60–2770 activates PKG in isolated cardiac tissue. BAY 60–2770 was perfused at 5 nM or 5 μM for 10 min in a Langendorff system. cGMP (A) and cAMP (B) concentrations in tissue homogenates were measured. Western blot analysis was used to determine VASP phosphorylation at ser239 (C), and the ratio of phospho-VASP to VASP was analyzed (D). PKG activity was examined using the CycLex cGK/PKG Assay (E). All the experiments were performed duplicated or triplicated in 3 animals from each group. *p <0.05, **p <0.005 vs. IR.

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  Fig 3. PKG mediates BAY 60-2770-induced cardioprotection. BAY 60–2770 (5 nM) was perfused with KT-5823 (1 μM) or 5-HD (100 μM) for 30 min after global ischemia. The percent of infarct area to risk area was determined from hearts from 3 animals in each group (A). PKG activity (B), phosphorylation of VASP (C, D) and MAPKs (E, F) were analyzed duplicated in 3 animals from each group. **p <0.005, ***p <0.001 vs. IR. # p <0.05, ## p <0.005, ### p <0.001 vs. BAY. Hypoxia/reoxygenation (H/R) injury was established by 14 hr of hypoxia and 6 hr reoxygenation. BAY 60–2770 and KT-5823 were treated during H/R injury in H9c2 cells, and cells were stained with MitoSOX red and counter stained with Mitotracker green and DAPI. Confocal microscopic images were taken under 400 X magnification (Scale bar: 5 μm) (G). Relative fluorescence unit (RFU) of MitoSOX was measured with microplate fluorescence reader (Ex/Em 510/580 nm). Mean values of at least quardruple samples are shown (H). A schematic diagram of postulated molecular pathway of BAY 60–2770 in cardiac IR injury (I). PKG plays a role in lowering mitochondrial ROS formation and limiting infarct size in BAY 60–2770 treated IR injured heart. The…