Use of a nitric oxide precursor to protect pig myocutaneous flaps from ischemia-reperfusion injury Journal Article


Authors: Cordeiro, P. G.; Santamaria, E.; Hu, Q. Y.
Article Title: Use of a nitric oxide precursor to protect pig myocutaneous flaps from ischemia-reperfusion injury
Abstract: Nitric oxide is a radical with vasodilating properties that protects tissues from neutrophil-mediated ischemia-reperfusion injury in the heart and intestine. Previous studies in our laboratory suggested that L-arginine, a nitric oxide precursor, can protect skin flaps from ischemia-reperfusion injury. In this study, we examined the effects of L-arginine on the survival of myocutaneous flaps in a large animal model and established whether this effect was mediated by nitric oxide and neutrophils. Two superiorly based 15 x 7.5 cm epigastric myocutaneous island flaps were dissected in 15 Yorkshire pigs weighing 45 to 50 kg. One of the flaps was subjected to 6 hours of arterial ischemia and then reperfused for 4 hours (ischemia-reperfusion flaps), whereas the other flap was used as a non-ischemic control (non- ischemia-reperfusion flaps). The flaps were divided into four groups: control non-ischemia-reperfusion flaps that received only saline (group I); ischemia- reperfusion flaps that were treated with saline (group II); and flaps treated with either L-arginine (group III) or Nω-nitro-L-arginine methylester (L- NAME), a nitric oxide synthase competitive inhibitor, plus L-arginine in equimolar amounts (group IV). These drugs were administered as an intravenous bolus 10 minutes before the onset of reperfusion, followed by a 1-hour continuous intravenous infusion. Full-thickness muscle biopsies were taken at baseline, 3 and 6 hours of ischemia, and 1 and 4 hours of reperfusion. The biopsies were evaluated by counting neutrophils and measuring myeloperoxidase activity. At the end of the experiment, skeletal muscle necrosis was quantified using the nitroblue tetrazolium staining technique, and a full- thickness biopsy of each flap was used for determination of water content. Statistical analysis was performed using analysis of variance and the Newman- Keuls test. Non-ischemia-reperfusion flaps showed no muscle necrosis. Ischemia-reperfusion flaps treated with saline had 68.7 ± 9.1 percent necrosis, which was reduced to 21.9 ± 13.6 percent with L-arginine (p < 0.05). L-NAME administered concomitantly with L-arginine demonstrated a necrosis rate similar to that of saline-treated ischemia-reperfusion flaps (61.0 ± 17.6 percent). Neutrophil counts and myeloperoxidase activity after 4 hours of reperfusion were significantly higher in ischemia-reperfusion flaps treated with L-NAME and L-arginine as compared with the other three groups (p < 0.05). Flap water content increased significantly in ischemia- reperfusion flaps treated with saline and L-NAME plus L-arginine versus non- ischemia-reperfusion flaps (p < 0.02) and L-arginine-treated ischemia- reperfusion flaps (p < 0.05). There was no difference in flap water content between ischemia-reperfusion flaps treated with L-arginine and non-ischemia- reperfusion flaps. Administration of L-arginine before and during the initial hour of reperfusion significantly reduced the extent of flap necrosis, neutrophil accumulation, and edema due to ischemia-reperfusion injury in a large animal model. This protective effect is completely negated by the use of the nitric oxide synthase blocker L-NAME. The mechanism of action seems to be related to nitric oxide-mediated suppression of ischemia-reperfusion injury through neutrophil activity inhibition.
Keywords: controlled study; surgical flaps; nonhuman; peroxidase; animals; animal tissue; myeloperoxidase; animal experiment; animal model; enzyme activity; necrosis; neutrophil; drug mechanism; ischemia; enzyme inhibitors; neutrophils; muscle biopsy; leukocyte count; water; myocutaneous flap; swine; arginine; nitric oxide synthase; intravenous drug administration; muscles; nitric oxide; tetrazolium salts; reperfusion injury; female; priority journal; article; muscle necrosis; nitroblue tetrazolium; n(g) nitroarginine; water content; ng-nitroarginine methyl ester
Journal Title: Plastic and Reconstructive Surgery
Volume: 102
Issue: 6
ISSN: 0032-1052
Publisher: Lippincott Williams & Wilkins  
Date Published: 1998-11-01
Start Page: 2040
End Page: 2048
Language: English
PUBMED: 9811002
PROVIDER: scopus
DOI: 10.1097/00006534-199811000-00035
DOI/URL:
Notes: Article -- Export Date: 12 December 2016 -- Source: Scopus
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  1. Peter G Cordeiro
    282 Cordeiro
  2. Qun Ying Hu
    27 Hu