Hemorheological, morphological, and oxidative changes during ischemia-reperfusion of latissimus dorsi muscle flaps in a canine model.

Although ischemia-reperfusion (I/R) strongly influences muscle flap survival in reconstructive surgery, there is limited knowledge about its relation to hemorheological parameters and oxidative stress markers in flaps. In the present study we investigated these changes during I/R of latissimus dorsi muscle (LDM) flaps in beagle dogs. In four animals LDM flaps were prepared bilaterally. The right side served as control, while the left side's vascular pedicle was clamped for 60 minutes, and a 60-minute reperfusion was allowed afterward. Blood samples (0.5 ml each) were taken from the pedicle's vein bilaterally before and after the ischemia, and at the 5th, 15th, 30th, 45th, and 60th minutes of the reperfusion, for hematological and erythrocyte aggregation tests. In muscle biopsies, taken before and after I/R, histological investigations and tests for measuring gluthation-peroxidase (GSH-PX) activity, glutathione (GSH) and carbonyl concentrations, and thiobarbituric acid reactive substances (TBARS) content were carried out. In I/R side leukocyte count increased during the reperfusion with a peak at the 30th minute. Hematocrit continuously increased from the 15th minute. In the first 5 minutes of the reperfusion, erythrocyte aggregation increased, than tented to be normalized. In muscle homogenates GSH-PX activity did not change markedly, GSH content slightly decreased, carbonyl and TBARS content increased during reperfusion. A 1-hour ischemia and reperfusion of LDM flaps caused local changes of leukocyte distribution and erythrocyte aggregation, supposedly due to the metabolic and inflammatory reactions. Oxidative damage during reperfusion was also demonstrated.