Effect of the expression of VEGF protein in the lung and ultrastructure of pulmonary vascular endothelial cell in neonatal rats with hyperoria.

Objective: To explore the dynamic changes of the expression of VEGF protein in the lung and ultrastructure of pulmonary vascular endothelial cell in neonatal rats with hyperoxia. Methods: Sixty neonatal rats were randomly divided into 2 group ( n =30) : experimental group with CLD induced by hyperoxia,and control group. The expression of VEGF protein in the lung was determined by using immunohistochemical methods. We observed the changes of ultrastructure of pulmonary vascular endothelial cell by using TEM. Results: The VEGF protein was mainly expressed in the epithelium of the conductive airway on the 1 day and gradually increased in distant epithelial cells after the 3th day in the control group. But in the experimental group with CLD induced by hyperoxia, the expression level of VEGF protein was very lower than that of the control group on the 7th day and to the lowest level on days 14; It was hardly to see the VEGF positive cells on 14d,21d;There was no significient difference between the two group on Id,3d P 0. 05 ,but on 7d, 14d,21d, P 0. 01. In the experimental group, changes of ultrastructure of pulmonary capillary endothelial cell was Characterized by endothelial cell and mitochondria swelled, capillary basement membrane unequal. Conclusion: Between decreased expression of VEGF protein and the injuries of pulmonary capillary endothelial cell might play an important role in the development of pulmonary vascular dys plasia in hyperoxia - induced chronic lung disease.