Correlation of Neutrophil Activation and Skin Flap Survival in Pharmacologically Altered Pigs

Abstract

In inflamed tissue, neutrophils produce tissue necrosis factors such as free oxygen radicals. We investigated the role of neutrophils in random flap survival using the tissue neutrophil marker myeloperoxidase (MPO), and in whole blood using flow cytometry with the neutrophil activation marker 2′7′ dichlorofluorescein diacetate. Hypopigmented pigs were treated with the experimental 21-aminosteroid lipid antioxidant U-74389G (oxygen free radical scavenger) before dorsal random skin flaps were elevated. Extent of flap survival was measured by surface planimetry 7 days after surgery. Mean flap survival was 64.1% ± 3.4% in the 3-mg/kg—treated group, and 68.0% ± 3.4% in the 1-mg/kg—treated group — both significantly greater than the survival in vehicle-treated controls (48.6% ± 2.3%). We measured MPO in tissue extracts using an enzyme-linked immunoassay, which showed less MPO in treated animals than in controls. Flow cytometry results were nonspecific. These data suggest that U-74389G improves random skin flap viability by inhibiting neutrophil infiltration into the flap.