Perfluorocarbon emulsion prevents eicoasanoid release in skeletal muscle ischemia and reperfusion

Eicosanoids play an important role in mediating deleterious effects following skeletal muscle ischemia-reperfusion injury. It has previously been shown that oxygenated perfluorocarbon emulsion (O2 Fluosol-DA 20%) decreases the amount of muscle necrosis and neutrophil sequestration when given during the reperfusion phase following skeletal muscle ischemia. As thromboxane is known to alter the endothelial cytoskeleton, thereby favoring diapedesis of neutrophils, the effects of O2 Fluosol-DA 20% on thromboxane release in a canine gracilis muscle model were investigated. The gracilis muscle on one randomly selected side of 14 adult mongrel dogs (body-weight 22-26 kg) was subjected to 6 h of normothermic ischemia followed by 48 h of normothermic reperfusion. The control group (n = 7) underwent ischemia-reperfusion, but without any pharmacological intervention. The Fluosol group (n = 7) were infused with O2 Fluosol-DA 20% (4.3(0.2) ml O2/100 ml) at 12 ml/min for 40 min via the gracilis artery following the ischemic period. Thromboxane B2 levels were measured from blood samples obtained at pre-ischemia, and at 1 h and 48 h of reperfusion. The gracilis muscles were harvested at the end of the experiment and extent of muscle necrosis quantitated by serial transections, nitroblue tetrazolium staining and computed planimetry. The mean(s.e.m.) muscle necrosis in the control group (59(6)%) was significantly higher than in the Fluosol group (22(5)%, P < 0.05, t-test). Thromboxane levels (pg/ml) in the control group at 1 h of reperfusion were significantly higher than the pre-ischemic and 48-h reperfusion levels (7286(1383) versus 1336(592) and 2314(1297), P < 0.05 by ANOVA and Student-Newman-Keuls test). The thromboxane level in the Fluosol group at 1 h reperfusion was significantly lower than the control group (2700(556) and 7286(1383) pg/ml, respectively; P < 0.05, t-test). In contrast, there was no statistically significant difference between thromboxane levels in the Fluosol group at 1 h reperfusion compared with levels at pre-ischemia and 48 h reperfusion (2700(556) versus 1336(592) and 1400(474). Thus, perfluorocarbons are effective in decreasing skeletal muscle necrosis, probably by maintaining the endothelial integrity and preventing vasospasm, secondary to their inhibitory effect on thromboxane release. Perfluorocarbons may also minimize some of the deleterious pulmonary effects known to be caused by increased levels of eicosanoids during reperfusion.