Objective:To investigate whether LMWH can protect the function of umbilical cells in hypoxia and hypoxia-reoxygenation conditions.Methods:Human umbilical vein endothelial cells

—ECV304

were planted into 6-well dishes

then cultivated respectively in three conditions:normal

hypoxia and hypoxia-reoxygenation conditions.Cells were grown for 1 hour in hypoxia condition;reoxygenated for 6 or 24 hours after 1 hour hypoxia

respectively.Cells in hypoxia and hypoxia-reoxygenation conditions were divided into two subgroups:LMWH group (5IU/ml) and control group.At each end of incubation time the medium was removed from each well.NO and MDA were measured by chromatometry.ET were measured by radioimmunoassay.Results:There was a decrease in the biosythesis and release of NO

while an increase of MDA and ET in hypoxia and hypoxia-reoxygenation conditions.The effect in hypoxia-reoxygenation condition was more remarkable than in hypoxia condition.But in both conditions LMWH could inhibit the productions of MDA and ET

increase the productions of NO.Conclusion:In hypoxia and hypoxia-reoxygenation conditions

LMWH can inhibit the production of MDA

and protect endothelial cells from oxygen free radicals.