Local Application Of Dexamethasone Preventing Restenosis Of Autografted Vein

Objective:To observation influence of application dexamethasone on the New Zealand rabbit autologous vein graft restenosis and to explore its mechanism.Methods:The establish ment of autografted venous model was used with external jugularvein-arteria carotis transplantation in New Zealand rabbit. According to the administration condition after autografted venous transPlantation,30 New Zealand rabbits were randomly classified into three groups: (A) Blank control group (B) fibrin group (C) dexamethasone group. At 3 week after transPlantation, the vein grafts were harvested. The grafts were stained with HE to observe the thickness of the intima and Lymphocyte number ,were stained with proliferating cell nuclear antigen(PCNA) to study the proliferation of the wall cells.The terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling(TUNEL) method was used to detect in situ apoptosis.Results:1.Macroscopic observation:All the experimental animals survived when the experiment completed.The patency rate of the vein grafts was 100%and there was no rupture of the vein grafts until they were harvested. The fibrin glue has been absorbed, the organizational structure level is clear, the blood vessel and the peritonsillar tissue do not have the adhesion, the vein putsation is good, does not have angioma and the vascular occlusion formation when the vein grafts were harvested.2.Morphology: Three weeks after the transplantation,HE staining showed that the the thickness of the intima and Lymphocyte number of the Group C is less than Group A and Group B(p﹤0.05). the the thickness of the intima of Group B is less than Group A,but lymphocyte number not remarkable difference(p﹥0.05).3.Immunohistochemistry of PCNA:Three weeks after the transplantation,there were less PCNA positive cells in the intima in Group C(24.91%±1.51%) than Group A(41.37%±2.41%) or Group B(39.14%±1.74%) . The percent of PCNA positive cells in the intima of the Group A was more than Group B(P<0.05).4. The detect of cell apoptosis in situ by TUNEL:The percentage of TUNEL positive cells in Group C(20.68%±1.45%)is more than Group A(15.33%±1.56%) or Group B(18.83%±0.74%) (P<0.05)in the three weeks after operation. The percentage of TUNEL positive cells in Group B) is more than Group A (P<0.05).Conclusions:1.Dexamethasone can reduce the expression of PCNA in vein vascular smooth muscle in the autogenous graft, enhance the expression of TUNEL in vein vascular smooth muscle in the autogenous graft, thus Prevention transplant vein again narrow.2.The fibrin glue as a very good medicine also have well prevents the vein graft to be restenosis.