PPAR-alpha activation as a preconditioning-like intervention in rats in vivo confers myocardial protection against acute ischaemia-reperfusion injury: involvement of PI3K-Akt

Can J Physiol Pharmacol. 2012 Aug;90(8):1135-44. doi: 10.1139/y2012-052. Epub 2012 Jul 18.

Abstract

Peroxisome proliferator-activated receptors (PPAR) regulate the expression of genes involved in lipid metabolism, energy production, and inflammation. Their role in ischaemia-reperfusion (I/R) is less clear, although research indicates involvement of PPARs in some forms of preconditioning. This study aimed to explore the effects of PPAR-α activation on the I/R injury and potential cardioprotective downstream mechanisms involved. Langendorff-perfused hearts of rats pretreated with the selective PPAR-α agonist WY-14643 (WY, pirinixic acid; 3 mg·(kg body mass)·day(-1); 5 days) were subjected to 30 min ischaemia - 2 h reperfusion with or without the phosphatidylinositol 3-kinase (PI3K)-Akt inhibitor wortmannin for the evaluation of functional (left ventricular developed pressure, LVDP) recovery, infarct size (IS), and reperfusion-induced arrhythmias. A 2-fold increase in baseline PPAR-α mRNA levels (qPCR) in the WY-treated group and higher post-I/R PPAR-α levels compared with those in untreated controls were accompanied by similar changes in the expression of PPAR-α target genes PDK4 and mCPT-1, regulating glucose and fatty acid metabolism, and by enhanced Akt phosphorylation. Post-ischaemic LVDP restoration in WY-treated hearts reached 60% ± 9% of the pre-ischaemic values compared with 24% ± 3% in the control hearts (P < 0.05), coupled with reduced IS and incidence of ventricular fibrillation that was blunted by wortmannin. Results indicate that PPAR-α up-regulation may confer preconditioning-like protection via metabolic effects. Downstream mechanisms of PPAR-α-mediated cardioprotection may involve PI3K-Akt activation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Androstadienes / pharmacology
  • Animals
  • Arrhythmias, Cardiac / complications
  • Arrhythmias, Cardiac / physiopathology
  • Arrhythmias, Cardiac / prevention & control
  • Chymases / biosynthesis
  • Disease Models, Animal
  • Male
  • Myocardial Infarction / complications
  • Myocardial Infarction / physiopathology
  • Myocardial Infarction / prevention & control
  • Myocardial Reperfusion Injury / complications
  • Myocardial Reperfusion Injury / metabolism
  • Myocardial Reperfusion Injury / physiopathology*
  • Myocardial Reperfusion Injury / prevention & control*
  • PPAR alpha / biosynthesis
  • PPAR alpha / physiology*
  • Peroxisome Proliferators / antagonists & inhibitors
  • Peroxisome Proliferators / pharmacology
  • Peroxisome Proliferators / therapeutic use
  • Phosphatidylinositol 3-Kinase / physiology*
  • Phosphoinositide-3 Kinase Inhibitors
  • Phosphorylation
  • Protein Kinase Inhibitors / pharmacology
  • Protein Kinases / biosynthesis
  • Proto-Oncogene Proteins c-akt / antagonists & inhibitors
  • Proto-Oncogene Proteins c-akt / metabolism
  • Proto-Oncogene Proteins c-akt / physiology*
  • Pyrimidines / antagonists & inhibitors
  • Pyrimidines / pharmacology
  • Pyrimidines / therapeutic use
  • Rats
  • Rats, Wistar
  • Signal Transduction / drug effects
  • Signal Transduction / physiology
  • Up-Regulation / drug effects
  • Up-Regulation / physiology
  • Wortmannin

Substances

  • Androstadienes
  • PPAR alpha
  • Peroxisome Proliferators
  • Phosphoinositide-3 Kinase Inhibitors
  • Protein Kinase Inhibitors
  • Pyrimidines
  • pirinixic acid
  • Protein Kinases
  • pyruvate dehydrogenase kinase 4
  • Phosphatidylinositol 3-Kinase
  • Proto-Oncogene Proteins c-akt
  • Chymases
  • Mcpt1 protein, rat
  • Wortmannin