Sevoflurane-induced cardioprotection depends on PKC-alpha activation via production of reactive oxygen species.
BACKGROUND
We previously demonstrated the involvement of the Ca2+-independent protein kinase C-delta (PKC-delta) isoform in sevoflurane-induced cardioprotection against ischaemia and reperfusion (I/R) injury. Since sevoflurane is known to modulate myocardial Ca2+-handling directly, in this study we investigated the role of the Ca2+-dependent PKC-alpha isoform in sevoflurane-induced cardioprotective signalling in relation to reactive oxygen species (ROS), adenosine triphosphate-sensitive mitochondrial K+ (mitoK+(ATP)) channels, and PKC-delta.


METHODS
Preconditioned (15 min 3.8 vol% sevoflurane) isolated rat right ventricular trabeculae were subjected to I/R, consisting of 40 min superfusion with hypoxic, glucose-free buffer, followed by normoxic glucose-containing buffer for 60 min. After reperfusion, contractile recovery was expressed as percentage of force development before I/R. The role of PKC-alpha, ROS, mitoK+(ATP) channels, and PKC-delta was established using the following pharmacological inhibitors: Go6976 (GO; 50 nM), n-(2-mercaptopropionyl)-glycine (MPG; 300 microM), 5-hydroxydecanoic acid sodium (5HD; 100 microM), and rottlerin (ROT; 1 microM).


RESULTS
Preconditioning of trabeculae with sevoflurane improved contractile recovery after I/R [65 (3)% (I/R + SEVO) vs 47 (3)% (I/R); n = 8; P < 0.05]. This cardioprotective effect was attenuated in trabeculae treated with GO [42 (4)% (I/R + SEVO + GO); P > 0.05 vs (I/R)]. In sevoflurane-treated trabeculae, PKC-alpha translocated towards mitochondria, as shown by immunofluorescent co-localization analysis. GO and MPG, but not 5HD or ROT, abolished this translocation.


CONCLUSIONS
Sevoflurane improves post-ischaemic contractile recovery via activation of PKC-alpha. ROS production, but not opening of mitoK+(ATP) channels, precedes PKC-alpha translocation towards mitochondria. This study shows the involvement of Ca2+-dependent PKC-alpha in addition to the well-established role of Ca2+-independent PKC isoforms in sevoflurane-induced cardioprotection.
Bouwman
R A
RA
VU University Medical Center (VUMC), Department of Anaesthesiology, Institute for Cardiovascular Research Vrije Universiteit (ICaR-VU), De Boelelaan 1117, 1081 HV Amsterdam, The Netherlands. a.bouwman@vumc.nl
Musters
R J P
RJ
van Beek-Harmsen
B J
BJ
de Lange
J J
JJ
Lamberts
R R
RR
Loer
S A
SA
Boer
C
C
D018685:Anesthetics, Inhalation / Q000494:pharmacology*; D000818:Animals; D002118:Calcium / Q000502:physiology; D004789:Enzyme Activation / Q000187:drug effects; D019157:Ischemic Preconditioning, Myocardial / Q000379:methods*; D008297:Male; D008738:Methyl Ethers / Q000494:pharmacology*; D009200:Myocardial Contraction / Q000187:drug effects / Q000502:physiology; D051571:Protein Kinase C-alpha / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D017382:Reactive Oxygen Species / Q000378:metabolism*; D000077149:Sevoflurane; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D046509:Tissue Culture Techniques; D014178:Translocation, Genetic
D018685:Anesthetics, Inhalation; D008738:Methyl Ethers; D017382:Reactive Oxygen Species; D000077149:Sevoflurane; D051571:Protein Kinase C-alpha; D002118:Calcium