Postconditioning with a CpG containing oligodeoxynucleotide ameliorates myocardial infarction in a murine closed-chest model

Life Sci. 2014 Dec 5;119(1-2):1-8. doi: 10.1016/j.lfs.2014.09.029. Epub 2014 Oct 29.

Abstract

Aims: Toll-like receptor (TLR)9 ligand CpG-oligodeoxynucleotide (CpG-ODN) exerts preconditioning in myocardial ischemia/reperfusion. We hypothesized a postconditioning effect of CpG-ODN in a murine closed-chest model of myocardial infarction.

Materials and methods: C57BL/6 (12 weeks, male, WT) mice were instrumented at the left anterior descending artery, then allowed 5d of recovery before 30 min ischemia. Treatments comprised: 1) PBS: 250 μl phosphate buffer solution intraperitoneally 5 min before reperfusion and 2) IPC (ischemic postconditioning): 3 twenty-second reperfusion and occlusion episodes at the end of ischemia 3) CpG-ODN: 1668 thioate 0.2 μmol/kg BW intraperitoneally 5 min before reperfusion. Infarct size was assessed via triphenyltetrazolium chloride (TTC) staining after 2 and 24h reperfusion. Myocardial mRNA-expression of cytokines was measured using real-time PCR after 2h reperfusion. Phosphatidylinositol-3 kinase (PI3K)-inhibitor wortmannin was injected intraperitoneally in WT 15 min before postconditioning and PBS in each group. Cardiac function in WT was assessed with a left-ventricular pressure-volume catheter at 24h reperfusion.

Key findings: Following 30 min ischemia and 2h reperfusion, infarct size was diminished by 90% in WT postconditioned with CpG-ODN (2.4 ± 1.55 IS/AAR%) and IPC (1.98 ± 1.03 IS/AAR%) compared to PBS mice (23.2 ± 3.97 IS/AAR%). Infarct size increased following 24h reperfusion but the differences remained robust. Expression of TNF-α and IL-10 was increased in CpG-ODN. Wortmannin abolished the postconditioning effect of CpG-ODN and IPC. Ejection fraction and preload-recruitable stroke work were significantly greater in CpG-ODN mice.

Significance: CpG-ODN confers postconditioning via activation of TLR9. Cardiac function is preserved following CpG-ODN postconditioning. The PI3K -inhibitor wortmannin attenuates CpG-ODN postconditioning.

Keywords: Toll-like receptor; cytokines; innate immunity; myocardial infarction; postconditioning.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adjuvants, Immunologic / therapeutic use*
  • Animals
  • Coronary Vessels / drug effects
  • Coronary Vessels / immunology
  • Coronary Vessels / metabolism
  • Coronary Vessels / pathology
  • Cytokines / genetics
  • Gene Expression Regulation / drug effects
  • Heart / drug effects
  • Heart / physiopathology
  • Immunity, Innate / drug effects
  • Ischemic Postconditioning / methods*
  • Male
  • Mice, Inbred C57BL
  • Myocardial Infarction / immunology
  • Myocardial Infarction / pathology
  • Myocardial Infarction / physiopathology
  • Myocardial Infarction / therapy*
  • Myocardium / immunology
  • Myocardium / metabolism
  • Myocardium / pathology*
  • Oligodeoxyribonucleotides / therapeutic use*
  • Phosphatidylinositol 3-Kinases / immunology
  • Phosphoinositide-3 Kinase Inhibitors
  • RNA, Messenger / genetics
  • Toll-Like Receptor 9 / immunology*

Substances

  • Adjuvants, Immunologic
  • CPG-oligonucleotide
  • Cytokines
  • Oligodeoxyribonucleotides
  • Phosphoinositide-3 Kinase Inhibitors
  • RNA, Messenger
  • Tlr9 protein, mouse
  • Toll-Like Receptor 9