Expression and significance of early growth response gene-1 in autogenous vein graft in rats

Objective: To investigate the development and significance of the expression of early growth response gene-1(Egr-1) in autogenous vein graft in rats and to detect the role of Egr-1 in intimal hyperplasia(IH).Methods:Autogenous vein graft model was established in 80 Wistar rats.Egr-1 mRNA was measured by RT-PCR and in situ hybridization.Western blotting and immunohistochemical method were used to detect the expression of Egr-1 protein.Results:The expression of Egr-1 mRNA and Egr-1 protein had biphasic changes.The level of Egr-1 mRNA increased rapidly 1 hour after graft,and the positive expression rate of Egr-1 mRNA was(35±7)%.Then the level declined 6 hours and 24 hours later.The level increased again l week later and reached the peak 4 weeks later,and the positive expression rate of Egr-1 mRNA was(45±6)%.Immunohistochemical staining and Western blotting revealed that Egr-1 protein expressed at the 2nd hour in early phase and that the positive expression rate of Egr-1 protein was(30±5)%.The high expression continued for 6 hours.The level of Egr-1 protein decreased 24 hours and 3 days later.The positive expression rate of Egr-1 protein reached the peak of(40±9)% at the 4th week.Conclusion:In autogenous vein graft,Egr-1 plays an important role in the proliferation of vascular smooth muscle cells.Egr-1 may become a new target for the prevention and therapy of intimal hyperplasia,stenosis,and emphraxis after vein graft.