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

Objective To investigate the expression of early growth response gene-1 in autogenous vein graft in rats, and its role in intimal hyperplasia (IH).Methods Autogenous vein graft model was established in 90 Wistar rats. Grafts were harvested at 1、2、6、24 hours, and 3、7、14、28、42 days after surgery. Normal veins serve as control. Egr-1 mRNA was measured by RT-PCR and in situ hybridization. Western blotting and immunohistochemistry were used to detect the protein expression of Egr-1. Results The expression of Egr-1 mRNA and Egr-1 protein experienced biphasic changes. At 1 hour, the value of gene expression of Egr-1 mRNA was 2. 21±0. 85, declining at 6 and 24 hours, and upgrading at 7 days, culminating at 3.16±1.14 at 28 days. Egr-1 protein expression was detected at 2 hours, with the positive expression rate of 31%±6%. The level of Egr-1 protein was decreased from 24 hours to 3 days. A peak was reached at 41%±8% at 28 days. Immunoreative Egr-1 was located within vascular smooth muscle cells (VSMCs) and monocytes/macrophages in the media at the early phase of day 7 and 14, and in neointimal and medial VSMCs at later phase of day 28. Egr-1 was also present in the endolumial endothelial cells. Conclusion In autogenous vein graft, Egr-1 plays an important role in the proliferation of VSMCs in autogenous vein graft.