Lazaroid U74500A as an additive to University of Wisconsin solution for pulmonary grafts in the rat transplant model

Lazaroids are a class of novel 21 aminosteroids. They have been reported to be potent inhibitors of lipid peroxidation, which is a major contributing factor to ischemia-reperfusion injury in the lung. A Lewis rat orthotopic left lung isotransplant model was used to investigate the effects of the lazaroid U74500A on pulmonary preservation. The heart-lung blocks of donor rats were flushed with and then stored in either standard University of Wisconsin solution or University of Wisconsin solution with 30 μmol/L of U74500A substituted for the dexamethasone. After 6 or 12 hours of cold storage at 0° C, the left lungs were transplanted into recipient rats and reperfused for 1 hour. Pulmonary function was assessed by measuring oxygen and carbon dioxide tensions in arterial blood after removal of the right lung. Lipid peroxide concentrations were measured as a thiobarbituric acid- reactive substance. Although arterial oxygen and carbon dioxide pressures and water content after 6 hours of preservation followed by reperfusion were similar in both the lazaroid and dexamethasone groups, lipid peroxide concentration was significantly higher in the dexamethasone group (0.88 ± 0.07 μmol/gm) than in the lazaroid group (0.54 ± 0.07 μmol/gm) (p < 0.01). After 12 hours of preservation, there were significant differences between the lazaroid and dexamethasone groups in arterial oxygen pressure (339 ± 70 vs 27 ± 3 mm Hg, p < 0.01), arterial carbon dioxide pressure (24.3 ± 2.7 vs 47.7 ± 7.0 mm Hg, p < 0.001), and lipid peroxide concentrations (0.69 ± 0.07 vs 1.30 ± 0.09 μmol/gm, p < 0.001). We conclude that addition of U74500A to the flush and storage solution enhances the preservation of the pulmonary graft in this transplant model.