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Figure 1. Role of vascular endothelial growth factor cell signaling in I/R-mediated lung injury in rats. A) Pretreatment with Ad Flk1-Fc, an adenovirus encoding the soluble vascular endothelial growth factor receptor type II, prevents I/R-mediated lung injury in rats. Extravascular plasma equivalents (µl/lung) are shown for control and ischemic lungs of rats that have been pretreated with Ad Flk1-Fc (109 pfu), or with Ad GFP (109 pfu), (30 min ischemia and 180 min reperfusion); results are shown as means ± SEM; *P < 0.05 from control lung. B) Effect of I/R injury on lung tissue vascular endothelial growth factor concentration in rats. Vascular endothelial growth factor concentrations were measured by ELISA in rat lungs that underwent I/R lung injury (30 min ischemia and 180 min reperfusion) or sham surgery; results are shown as means ± SEM. C) Effect of I/R injury and inhibition of VEGF cell signaling with Ad Flk1-Fc, on lung tissue VEGF receptor type II (KDR/flk-1) phosphorylation in rats. KDR/flk-1 phosphorylation was measured in the lungs of rats that underwent I/R lung injury or sham surgery; in some experiments, rats were pretreated with Ad Flk1-Fc (109 pfu) or with Ad GFP (109 pfu); lung tissues were harvested and subjected to immunoprecipitation with an Ab against VEGF receptor type II protein and immunoblotted with an Ab to phosphotyrosine. The same blots were then reprobed with an Ab to VEGF receptor type II protein. One representative blot is shown. For all experiments, densitometry analysis results are the mean ± SEM of four experiments; *P < 0.05 from control experiments.
