RESUMEN
Objective To investigate the gene expression of vascular endothelial growth factor(VEGF) and ultrastructural changes in cultured endothelial cells from human cerebral microvessels under hypoxic conditions.Methods Human cerebral microvessels were isolated from freshly obtained specimens of normal brain adherent to resected cerebral arteriovenous malformations.The expression of factor Ⅷ-relative antigen(FⅧ-RA) in cultured cells was observed with immunocytochemistry.The level of VEGFmRNA in cells and released VEGF protein in cell supernatant were determined by RT-PCR analysis and ELISA respectively when they were exposed to hypoxic conditions(95% N_2,5% CO_2;two hours,four hours,eight hours) or maintained in basal condition.Ultrastructural changes in cells were also observed by electron microscopy.Results In inverted microscope the cultured cells showed contact inhibition and a rounded cobblestone appearance.More than 90% of them were stained strongly with antibodies against FⅧ-RA.Significant VEGF mRNA and protein accumulated when these cells were exposed to hypoxia for 4 hours.However,their VEGF expression was down-regulated after hypoxia for 8 hours and a number of vesicles and swollen mitochondria were present in the cytoplasm.Conclusion The level of VEGF expression may havesignificant relationship with ultrastructural changes in human cerebral endothelial cells under hypoxic conditions.