Effects Of Paeoniflorin On Human Umbilical Vein Endothelial Cells Under Hypoxia

OBJECTIVES: Ischemic heart disease (IHD) is a cardial disorder caused by insufficient blood supply to a particular heart area and has become the first common cause of death around the world. Vascular endothelial cells act as the first barrier between tissue and blood which receive hypoxia at first. The study has revealed that vascular endothelial cells play an important role in coronary atherosclerotic heart disease. In our present study, we set up the stable and reliable hypoxic model in vitro on the basis of succeeding to culture the human umbilical vein endothelial cells (HUVEC). To observe the changes of SOD, MDA, LDH, nitric oxide, endothelial nitric oxide synthase, adhesion molecules and nuclear factor kappa B in HUVEC under hypoxia, and to further investigate the protective effects and its possible mechanisms of paeoniflorin on HUVEC under hypoxia.METHODS: Human umbilical vein endothelial cells (HUVEC) were cultured and go down to the future generation. After the third generation, experiments were divided into three groups: control group, cells were cultured under normal conditions; cells of hypoxia group were cultured in hypoxic box for 48 hour; paeoniflorin groups, HUVEC in paeoniflorin groups were given different dose paeoniflorin at the time of pre-hypoxia. The shape of cells was observed in phase contrast microscope. The concentrations of superoxide dismutase (SOD), Lactate dihydrogenase (LDH) activity, the content of malondialdehyde (MDA), and nitric oxide (NO) production were determined in cell medium. The level of eNOS, nuclear factor kappa B, ICAM-1 and VCAM-1 were examined by immunohistochemical method, cell ELISA method, immunohistochemical method, respectively.RESULTS: The cells shrieked and became circular in hypoxia group, paeoniflorin made these changes disappear or become less. Compared with control group, the concentrations of SOD were lower but LDH activity and the content of MDA were higher in the hypoxic group, paeoniflorin could increase the concentrations of SOD and decrease LDH activity and the content of MDA in HUVEC under hypoxic. After HUVEC were cultured under hypoxic condition for 48h, the production of NO decreased from (85.263±9.336) μM·L^-1 to (36.842±6.316) μM·L^-1 (P<0.001). Paeoniflorin could enhance the production of NO, increase the expression of eNOS. Hypoxia increases the expression of ICAM-1, VCAM-1 and NF- κB in HUVEC, however paeoniflorin decreases the expression of ICAM-1, VCAM-1 and NF-κ B in HUVEC under hypoxia. CONCLUSION: Hypoxia could injury HUVEC and led to endothelial dysfunction, but paeoniflorin can protect function of HUVEC, the effects were attenuated by administration of different dose paeoniflorin in range of certain dose. Paeoniflorin could exhibit its protective effects against HUVEC injury by increasing the activity of SOD, decreasing LDH activity and the content of MDA in HUVEC under hypoxic. Paeoniflorin could protect the function of endothelial cells and enhance the production of NO by activating eNOS as well as decrease the expression of ICAM-1 and VCAM-1 by decreasing the activity of nuclear factor kappa B in HUVEC under hypoxia.