Inhibition of proliferation of intima of coronary artery after coronary artery bypass grafting in rabbits by sirolimus

Abstract

Objective To observe the inhibitory effect of sirolimus on the excessive proliferation of the intima of the coronary artery after coronary artery bypass grafting in rabbits. Methods Thirty big ear white rabbits were used in the control design. The coronary artery bypass graft on the any one side served as intervention group and coated with the Pluronic gel containing 0.3 mg sirolimus, and that on the other side served as the control group and coated with the Pluronic gel alone. After 4 weeks, the thickness of the coronary artery, the cell proliferation index and the number of p27kip1 positive cells were measured. Results The thickness of the coronary artery in the intervention group was (64.9±15.2) μm, which was significantly less than that in the control group (79.2±15.4) μm (t=1.639, P=0.007). Proliferation index in the intervention group was 30.8±7.5, significantly higher than that in the control group (21.2±10.3, t=0.731, P=0.044). Immunohistochemical staining revealed that the positive staining of of p27kip1 in coronary artery smooth muscle cells and endothelial cells was seen in the intervention group, and the number of p27kip1 positive cells in the single field was 3.9±2.4. But there was no positive expression of of p27kip1 in normal group and control group (t=1.157, P=0.025). Conclusion Sirolimus can inhibit the intimal hyperplasia of vein graft in rabbits, which is related to the up-regulation of p27kip1. Key words: Sirolimus; Vein graft; Restenosis