External Beam Irradiation Prevents Restenosis Of Femoral Artery In A Rabbit Restenosis Model And Affects PCNA Of VSMC

Object:To observe the effects of external beam irradiation(γray)on arterial restenosis and the dose-effect relation;To discuss the impact of EBR on neointimal proliferation and the role of proliferation in the process of RS with histopathological examination.Methods:After two week cholesterol-fed in 30 Newland rabbits and chemistry drug injury of endothelial cells of single femoral artery,the vescular RS model was set up.Twenty-four later rabbits were randomly divided into five groups.We procedured external beam irradiation (γray)at one side femoral artery,the absorbed dose were 0Gy,SGy,15Gy,25Gy and 35Gy respectively,the 0Gy group was served as controlled.After three weeks cholesterol-fed,rabbits were killed and fixed.Pathological sections of femoral arteries were observed with HE staining and light-microscope;Proliferation was examined using Immunohistochemical analysis of PCNA on the specimens.Results:After five weeks of external beam irradiation(γray),the results showed:(1)Light-microscope:Strong neointimal proliferation and strait lumen observed in the control vessel;there weren't obvious changes in 5Gy group(P＞0.05),and the results were similar between it and 0Gy group;compared with the control group,neointimal proliferation was significantly inhibited in 15Gy,25Gy and 35Gy group,which all significantly reduced neointimal and intima/medial thickness and increased the lumen area(P＜0.05);What's more,the effect was much more evident in 25Gy and 35Gy groups compared with 15Gy group(P＜0.01),but the results were similar in the two groups(25Gy versus 35Gy).(2)PCNA:PCNA positivc cell rate was 31.32±3.43(%)in control vessels;32.70±3.03(%)in 5Gy group vessels,22.53±3.22(%)in 15Gy group vessels,13.11±2.78(%)in 25Gy group vessels, 10.10±4.38(%)in 35Gy group vessels;except 5Gy vessels compared with the control and 25Gy vessels compared with 35Gy vessels(P＞0.05),a group compared with another group(P＜0.01),The dose-effectiveness relation was observed.Conclusions:External beam irradiation(γray)could prevent arterial restenosis effectively and safely in definite dose scope,and effects was related to the delivered dose.Inhibitting the neointimal proliferation may contribute to the preventing of restenosis,and the doseeffectiveness relation was also observed.