OBJECTIVETo evaluate the effects of TIMP-2 local gene transfer on atherosclerotic plaque.

METHODSAtherosclerosis models were induced by denuding femoral artery endothelium plus high lipid diet in rabbits. TIMP-2 gene was transferred locally by balloons eluted with pcDNA3-TIMP-2. RT-PCR and Western blot were performed to verify exogenous genes transfer. MMPs activity in atherosclerotic plaque was evaluated by zymography. HE and VG staining and automatic image analysis system were used for pathological analysis of atherosclerotic femoral arteries. The lumen area of the vessel and the collagen contents in the atherosclerotic plaque were measured.

RESULTSThe expression of TIMP-2 gene in pcDNA3-TIMP-2 transferred group was significantly higher than control-vector transferred group at the end of week 2 after operation and reached the peak at the end of week 4. Comparing with the control group, the expression of TIMP-2 protein in treated group was also higher at the end of week 2, 4, and 8 after operation. Correspondingly, the MMP-2 and MMP-9 activities were lower in treated group. The thickness of fibrous cap of atherosclerotic plaque and the amount of collagen of the lesion were increased significantly in treated group compared with the control group, but there were no significant differences in vessel lumen area.

CONCLUSIONTIMP-2 gene transfer locally in atherosclerotic plaque could inhibit the activities of MMP-2 and MMP-9 in the lesion, increase the thickness of fibrous cap and the amount of collagen of the lesion, but may have no effect on the degree of the stenosis.