Dietary polyunsaturated fatty acids alter myocardial protein kinase C expression and affect cardioprotection induced by chronic hypoxia.
We examined the influence of dietary fatty acid (FA) classes on the expression of protein kinase C (PKC) delta and epsilon in relation to the cardioprotective effects of chronic intermittent hypoxia (CIH). Adult male Wistar rats were fed a nonfat diet enriched with 10% lard (saturated FA [SFA]), fish oil (n-3 polyunsaturated FA [n-3 PUFA]), or corn oil (n-6 PUFA) for 10 weeks. After 4 weeks on the diet, each group was divided into two subgroups that were either exposed to CIH in a barochamber (7000 m, 8 hrs/ day) or kept at normoxia for an additional 5-6 weeks. A FA phospholipid profile and Western blot analysis of PKC were performed in left ventricles. Infarct size was assessed in anesthetized animals subjected to 20-min coronary artery occlusion and 3-hr reperfusion. CIH decreased the n-6/n-3 PUFA ratio in all groups by 23% independently of the initial value set by various diets. The combination of n-3 diet and CIH had a stronger antiarrhythmic effect during reperfusion than the n-3 diet alone; this effect was less pronounced in rats fed the n-6 diet. The normoxic n-6 group exhibited smaller infarctions (by 22%) than the n-3 group. CIH decreased the infarct size in n-3 and SFA groups (by 20% and 23%, respectively) but not in the n-6 group. Unlike PKC epsilon, the abundance of PKC delta in the myocardial particulate fraction was increased by CIH except for the n-6 group. Myocardial infarct size was negatively correlated (r=- 0.79) with the abundance of PKC delta in the particulate fraction. We conclude that lipid diets modify the infarct size-limiting effect of CIH by a mechanism that involves the PKC delta-dependent pathway.
Hlavácková
Markéta
M
Charles University, Faculty of Science, Department of Biochemistry, Hlavova 8, 128 43 Prague 2, Czech Republic.
Neckár
Jan
J
Jezková
Jana
J
Balková
Patricie
P
Stanková
Barbora
B
Nováková
Olga
O
Kolár
Frantisek
F
Novák
Frantisek
F
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002316:Cardiotonic Agents / Q000494:pharmacology; D004041:Dietary Fats / Q000494:pharmacology; D005227:Fatty Acids / Q000494:pharmacology; D015525:Fatty Acids, Omega-3 / Q000494:pharmacology*; D043371:Fatty Acids, Omega-6 / Q000494:pharmacology*; D006339:Heart Rate / Q000187:drug effects; D000860:Hypoxia / Q000201:enzymology* / Q000503:physiopathology; D008297:Male; D009203:Myocardial Infarction / Q000201:enzymology / Q000503:physiopathology; D015428:Myocardial Reperfusion Injury / Q000201:enzymology / Q000503:physiopathology; D009206:Myocardium / Q000201:enzymology; D051745:Protein Kinase C-delta / Q000378:metabolism*; D051744:Protein Kinase C-epsilon / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar
D002316:Cardiotonic Agents; D004041:Dietary Fats; D005227:Fatty Acids; D015525:Fatty Acids, Omega-3; D043371:Fatty Acids, Omega-6; D051745:Protein Kinase C-delta; D051744:Protein Kinase C-epsilon