Evaluation of lung VEGF-A transduction during hyperoxia-induced injury in rats

Abstract

BackgroundSince Vascular Endothelial Growth Factor (VEGF) is a main factor for endothelial survival, we evaluated whether VEGF transduction could ameliorate hyperoxia induced injury, which is associated with predominant endothelial injury.\n\nMethods and ResultsTransduction (induced 48 hours before hyperoxic exposure) using adenoviral vector (Ad.) for VEGF (1010 viral particles [VP]) increased moderately survival under hyperoxia (fraction of inspired oxygen [FIO2] >95%) as compared with Ad.Null (1010 VP) transduction, whereas VEGF transduction with a lower dose (5.109 VP) had no effect. After 48 hours of hyperoxia, Ad.VEGF transduction increased lung VEGF concentration, prevented the diffuse loss of capillary bed and induced patchy areas of endothelial cell proliferation (CD31 immunostaining) with interstitial inflammatory cell recruitment as compared to Ad. Null transduction. Hyperoxia was associated with diffuse apoptosis that was inhibited only in patchy areas of endothelial proliferation under VEGF transduction. Hyperoxia-induced alveolar inflammation was similar with Ad.Null and Ad.VEGF. Under normoxia, the high dose of VEGF transduction induced diffuse alveolar inflammation whereas the low dose did not suggesting a pro-inflammatory effect of VEGF that may have participated to increased survival under hyperoxia.\n\nConclusionsWe demonstrate that lung VEGF-A transduction despite inhibition of the loss of capillary bed has a marginal effect of on animal survival during hyperoxia-induced injury.