Activation of p38 MAPK induced by a multi-cycle ischaemic preconditioning protocol is associated with attenuated p38 MAPK activity during sustained ischaemia and reperfusion
Date
2001
Authors
Marais E.
Genade S.
Huisamen B.
Strijdom J.G.
Moolman J.A.
Lochner A.
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Abstract
The role of p38 mitogen-activated protein kinase (MAPK) in ischaemic preconditioning remains controversial. Since most previous studies focussed on events only during sustained ischaemia, the aim of this study was to establish the activation pattern of p38 MAPK during a multicycle preconditioning protocol, sustained ischaemia as well as reperfusion and to correlate these events with functional recovery of the isolated perfused rat heart. Isolated perfused rat hearts were preconditioned by 3 × 5 min global ischaemia followed by 25 min global ischaemia and 30 min reperfusion. Non-preconditioned hearts were subjected to 25 min global ischaemia and 30 min reperfusion. Hearts were freeze-clamped and p38 MAPK activation in tissue lysates was assessed by standard Western blotting techniques, using a dual phospho-p38 MAPK antibody as well as a non-radioactive IP-kinase assay. The results showed that transient dual phosphorylation and activation of p38 MAPK occurs during a 3 × 5 min preconditioning protocol: the activation was maximal during the first episode, becoming progressively lower during the second and third episodes, p38 MAPK activation was significantly less during both sustained ischaemia and reperfusion in preconditioned hearts, when compared with non-preconditioned hearts. Attenuation of p38 MAPK activity during sustained ischaemia and reperfusion was associated with improved functional recovery. The effect of inhibition of p38 MAPK activation on cardioprotection was further evaluated in adult, isolated cardiomyocytes. Administration of SB 203580 (1-10 μM) before and during the preconditioning protocol, had no effect on cell morphology and viability after 2 h hypoxia, compared to untreated preconditioned cardiomyocytes. When administered to non-preconditioned cells before the onset of 2 h hypoxia, it caused a significant improvement in both morphology and viability. In summary, the results suggest that attenuation of the kinase activity during sustained ischaemia and reperfusion may be an essential element of the preconditioning process. © 2001 Academic Press.
Description
Keywords
mitogen activated protein kinase, synaptophysin, animal cell, apoptosis, cell death, cell viability, conditioning, conference paper, enzyme activation, enzyme activity, enzyme phosphorylation, heart muscle ischemia, heart muscle perfusion, heart protection, hypoxia, isolated heart, mediator release, nonhuman, priority journal, rat, Animals, Cells, Cultured, Enzyme Activation, Enzyme Inhibitors, Imidazoles, Ischemic Preconditioning, Myocardial, Male, Mitogen-Activated Protein Kinases, Myocardial Ischemia, Myocardial Reperfusion, Myocardium, p38 Mitogen-Activated Protein Kinases, Pyridines, Rats, Rats, Wistar
Citation
Journal of Molecular and Cellular Cardiology
33
4
33
4