Effects of tetramethylpyrazine on vascular endothelial growth factor expression in hyperoxic lung injury of neonatal rats

【Objective】 To study the expression of vascular endothelial growth factor in hyperoxia induced lung injury in newborn rats and to observe the interfering effect of tetramethylpyrazine(TMP)on it.【Methods】 A total of 96clean Sprague-Dawley(SD)rats which were less than 12hours old were enroled in this study.The neonatal rats were randomly divided into 4groups:Ⅰ:air-exposedcontrol group;Ⅱ:air-exposed+TMP-treated group;Ⅲ:hyperoxia-exposed control group;Ⅳ:hyperoxia-exposed+TMP-treated group.The rats were sacrificed at postnatal days 3,7,14(8rats each time point)and their lungs were collected.the lung histophatholoical changes were observed by HE staining;The protein expression of platelet endothelial cell adhesion molecule-1(PECAM-1)and vascular endothelial growth factor(VEGF)were performed by immunostaining.Capillary density was quantified by measuring the area of PECAM-1immunostaining in proportion to the total area of parenchymal cells.【Results】 At 3d,7d,14dof the exposure,groupⅢ(treatment of hyperoxiaexposed rats)resulted in a significant decrease in RAC and Capillary density.The expressions of VEGF and CD-31protein after 3,7,14days of hyperoxia exposure decreased significantly in the group Ⅲ compared with group Ⅰ、Ⅱand Ⅳ(P 0.05).Lung pathologic changes(RAC and Capillary density)and the expression of VEGF and CD-31in groupⅣwere similar to those in groupⅠandⅡ(P0.05).【Conclusion】 Hyperoxia exposure inhibited the expression of lung VEGF in neonatal rats.Treatment with TMP during hyperoxia exposure is associated with improved alveolar structure.the potential mechanism might be that TMP can up regulates the expressions of VEGF in lung tissue.