In vivo fluorometric assessment of cyclosporine on mitochondrial function during myocardial ischemia and reperfusion.

Abstract

BACKGROUND:

Cyclosporine A (CsA) limits myocardial reperfusion injury and preserves mitochondrial integrity, but its influence on mitochondrial function has not been described in vivo. Auto-fluorescence of mitochondrial nicotinamide adenine dinucleotide and flavin adenine dinucleotide correlate with mitochondrial dysfunction. We hypothesized that CsA limits mitochondrial dysfunction and that fluorometry can quantify this influence.

METHODS:

Seventeen rabbits were studied: untreated (UnT, n = 7), CsA preinfarction (CsAp, n = 6), and CsA on reperfusion (CsAr, n = 4). Animals underwent 30 minutes of myocardial ischemia and 3 hours reperfusion. Infarct size was determined by staining. Nicotinamide adenine dinucleotide and flavin adenine dinucleotide fluorescence was continually measured in the risk area. The redox ratio was calculated [flavin adenine dinucleotide(f)/(flavin adenine dinucleotide(f) + nicotinamide adenine dinucleotide(f))]. Electron microscopy evaluated mitochondria morphology.

RESULTS:

The infarct size by group was 39.1% +/- 1.7% in CsAp, 39.1% +/- 1.7% in CsAr, and 53.4% +/- 1.9% in UnT (p < 0.001). During ischemia, the CsAp group demonstrated less hypoxic reduction, with the redox ratio decreasing to 75.6% +/- 4.1% of baseline. The UnT and CsAr groups deceased to 67.1% +/- 4.0% and 67.2% +/- 3.6%, respectively (p < 0.005). During reperfusion the UnT group redox ratio increased to 1.59 +/- 0.04 times baseline. This increase was blunted in the CsAp (1.17 +/- 0.04, p = 0.026) and CsAr (1.35 +/- 0.02, p = 0.056) groups. Electron microscopy revealed reduced mitochondrial disruption in CsAp (19.7% +/- 7.6%) and CsAr (18.1% +/- 7.1%) rabbits compared with UnT (53.3% +/- 12.5%).

CONCLUSIONS:

Fluorometric spectroscopy can be used in vivo to quantitatively assess the time course of CsA's influence on the mitochondrial dysfunction associated with myocardial ischemia and reperfusion.

• Authors: Muneaki Matsubara, Mahsa Ranji, Bradley G Leshnower, Mio Noma, Sarah J Ratcliffe, Britton Chance, Robert C Gorman, Joseph H Gorman 3rd
• Journal: The Annals of thoracic surgery (Ann Thorac Surg) Vol. 89 Issue 5 Pg. 1532-7 (May 2010) ISSN: 1552-6259 [Electronic] Netherlands
• PMID: 20417773 (Publication Type: Comparative Study, Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)
• Copyright: Copyright (c) 2010 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Chemical References

• Cyclosporine

Topics

• Animals
• Cyclosporine (pharmacology)
• Disease Models, Animal
• Immunohistochemistry
• Ischemic Preconditioning, Myocardial
• Mitochondria, Heart (drug effects, physiology)
• Myocardial Infarction (pathology, prevention & control)
• Myocardial Ischemia (pathology, therapy)
• Myocardial Reperfusion (methods)
• Myocardial Reperfusion Injury (pathology, prevention & control)
• Rabbits
• Random Allocation
• Reference Values
• Risk Assessment
• Spectrometry, Fluorescence