Objective:To compare the scanning electron microscopic changes of venous endothelium after acute inferior vein thrombosis in rats.Methods:The inferior caval venous thrombosis models were treated with heparin(n=35

group A)

urokinase(n=35

group B)

and combination of heparin and urokinase(n=35

group C)

respectively.Sham group(n=30)was also established.The thrombosed cav-al veins were taken 1

4

7

14

and 28 days after thrombosis.Scanning electron microscopy was used to observe the damage of endothelial cells.Results:The Results showed that the endotheliurn injury degree was mainlyⅡtoⅢgrade in group B and C whereas it wasⅢtoⅣ grade in group A on day7(P<0.05);endotheliurn injury degree was mainlyⅡgrade in group C whereas it wasⅢtoⅣgrade in group A and B on day 28(P<0.05).Conclusion:Combination of heparin and urokinase for the treatment of acute inferior caval venous thrombosis has good short or intermediate term effect on the protection of endothelial structure.