Effects of adenosine pretreatment on detection of free radicals in ischemic and reperfused canine gracilis muscle flaps by use of spin-trapping electron paramagnetic resonance spectroscopy.
OBJECTIVE
To determine whether adenosine pretreatment attenuates free radical production and muscle damage in ischemic and reperfused canine skeletal muscle.


METHODS
9 healthy mixed-breed dogs.


METHODS
Dogs were anesthetized, and both gracilis muscles were isolated, leaving only the major vascular pedicle intact. Saline (0.9% NaCl) solution was injected into the artery supplying the control flap, whereas adenosine (10 mg) was injected into the contralateral artery. Ischemia was induced in both flaps for 4 hours. alpha-Phenyl-N-tert-butylnitrone was administered IV to each dog 1 hour prior to reperfusion. Following 15 minutes of reperfusion, effluent blood samples from each muscle flap were obtained and processed for spin-trapping electron paramagnetic resonance (EPR) spectroscopy. Muscle biopsy specimens were obtained for histologic evaluation, and dogs were euthanatized.


RESULTS
EPR spectra of strong intensity were obtained from analysis of 5 of 9 paired samples. Signals identified were characteristic of oxygen- and carbon-centered free radical adducts. Signal intensity of spectra from adenosine-treated flaps was significantly less than that of control flaps; mean signal attenuation was 36% in the adenosine-treated group. Histologic evaluation of muscle flaps did not reveal significant differences between groups.


CONCLUSIONS
Treatment of canine muscle flaps with adenosine prior to a period of ischemia reduced but did not completely attenuate free radical production after reperfusion. However, adenosine pretreatment did not affect histologic abnormalities.
Brisson
Brigitte A
BA
Department of Clinical Studies Ontario Veterinary College, University of Guelph, Canada.
Miller
Craig W
CW
Chen
Guoman
G
McCutcheon
L Jill
LJ
Janzen
Edward G
EG
D000241:Adenosine / Q000494:pharmacology*; D000818:Animals; D003497:Cyclic N-Oxides; D004285:Dogs; D004578:Electron Spin Resonance Spectroscopy / Q000662:veterinary; D005609:Free Radicals / Q000032:analysis*; D007511:Ischemia / Q000378:metabolism / Q000662:veterinary; D018482:Muscle, Skeletal / Q000098:blood supply* / Q000187:drug effects / Q000378:metabolism; D009589:Nitrogen Oxides / Q000494:pharmacology; D015427:Reperfusion Injury / Q000378:metabolism / Q000662:veterinary*; D019097:Spin Trapping / Q000662:veterinary; D013524:Surgical Flaps / Q000662:veterinary
D003497:Cyclic N-Oxides; D005609:Free Radicals; D009589:Nitrogen Oxides; C029217:phenyl-N-tert-butylnitrone; D000241:Adenosine