Time Dependent Changes of Nitric Oxide Synthesis Following Anoxia and Reoxygenation of Endothelial Cells of Umbilical Vein

ABSTRACT

High systemic complication rates and severe tissue injuries are associated with more successful revascularization and reperfusion of ischemia rather than ischemia itself. It is regarded as a "ischemia- reperfusion (I/R) injury". It is well recognized that the microvasculature is highly sensitive to I/R and that the initial damage of endothelial cells contributes to I/R-induced tissue injury. The endothelial cells serve as an important modulator of vascular homeostases by secreting vasoactive materials. One of the important product of endothelial cells, nitric oxide helps to maintain hemostasis through its involvement in coagulation, platelet activation, vascular tone regulation. But The exact role of nitric oxide and time dependent change of its synthesis during the reperfusion injury are not clear. In this study, endothelial cells were isolated from human fetal umbilical vein and cultured in M-199 medium. We observed morphological change of the endothelial cells and time dependent change of nitric oxide synthesis following anoxia and reperfusion injuries. The results were as follows 1) More significantly, the endothelial cells of anoxia group were flattened and detached than contol group. More severe detachment of endothelial cells was founded in R-O group than anoxia group. There is no significant differences in morphological changes between allopurinol group and anoxia group. 2) The concentration of NO in the anoxia group (2511.62 428.60nM/1 105 cells/ml) was lower than that of the control group (3505.14 192.95nM/1 105 cells/ml) (P<0.005). The NO concentration of the reoxygenation group reached its highest level of 2953.14 90.98 nM/1 105 cells/ml at 180 minutes (P<0.05) and decreased thereafter. There was no significant differences in NO concentration between allopurinol group and anoxia group. In conclusion, morphologic damage of endothelial cells in reoxygenation group was significantly increased compared with anoxia group. Nitric oxide syntheses in reoxygenation group and anoxia group were decreased compared with control group. More advanced study will be needed to elucidate the detailed mechanism of time-dependent change of nitric oxide synthesis during the reperfusion injury.