Effect of Mimeng Flower decoction on VEGFR signal transduction pathway in human umbilical vascular endothelial cells under chronic hypoxia

Objective To study the mechanism of vascular endothelial growth factor(VEGF)-VEGF receptor(VEGFR) signal transduction,and discuss the effect of Mimeng Flower decoction on inhibiting the proliferation of human umbilical vascular endothelial cell(HUVEC) under chronic hypoxia.Methods HUVEC were cultured in vitro.CoCl 2 was used to set up the cell chemistry hypoxia model,in the same time,10 g·L-1 20 g·L-1,40 g·L-1 Mimeng Flower decoction extract were added to the HUVEC separately,the following studies were made after 24 hours incubation.The inhibitive effect of Mimeng Flower decoction on the proliferation of HUVEC under chronic hypoxia was investigated by WST-8 method.The effects of Mimeng Flower decoction on phosphorylation level of VEGF,fms-like tyrosine kinase-1(Flt-1) and fetal liver kinase-1 /kinase insert domain-containing receptor(Flk-1 /KDR) in HUVEC were detected by Western blot method.The protein expression of intercellular adhesion molecule-1(ICAM-1) in HUVEC was detected by immunohistochemistry method.Results WST-8 methods showed that the IOD in hypoxic group was 1.112 ± 0.060,which in each Mimeng Flower decoction group were 0.860 ± 0.050,0.567 ± 0.072 and 0.263 ± 0.057,indicated that the Mimeng Flower decoction could effective inhibit the proliferation of HUVEC(both P 0.01).The results of Western blot showed that the phosphorylation levels of VEGF,Flk-1 /KDR in hypoxic group were 1.922 ± 0.048,1.341 ± 0.054,which higher than those in normal group,Flt-1 in hypoxic group was 1.265 ± 0.065,which lower than that in normal group,there were significant differences(both P 0.01).The results of immunohistochemistry method showed that IOD of ICAM-1 in normal group and hypoxic group were 161.416 ± 4.905,213.464 ± 10.282,which in each Mimeng Flower decoction group were 186.841 ± 9.039,171.862 ± 8.202 and 165.053 ± 6.088.Mimeng Flower decoction could down-regulate the expression of ICAM-1.Conclusion Mimeng Flower decoction can markedly inhibit the HUVEC proliferation under chronic hypoxia,the effect mechanism include down-regulating the phosphorylation level of VEGF,Flk-1 /KDR,up-regulating phosphorylation level of Flt-1 and interfering the VEGF-VEGFR signal transduction pathway.