Effect of Radiotherapy on Restenosis after Angioplasty in Rabbits Iliac Artery Atherosclerosis

Objective To observe the dose effect relation of endovascular brachytherapy with 32 P preventing restenosis after angioplasty and to assess the possible mechanisms of irradiation therapy reducing restenosis.Methods After ballon endothelial injury of iliac arteries and six weeks cholesterol fed in 24 rabbits,the double iliac artery atherosclerotic stenosis model was set up.We procedured angioplasty and 32 P brachytherapy at one side randomly,the absorbed doses were 9 1Gy,21 8Gy and 33 4Gy,respectively,the other side non radiative therapy was served as self controled.After five weeks,the iliac artery angiography was performed,pathological sections of iliac arteries were observed with light microscope,transmisson electron nuclear factor κB(NF κB)?insulin like growth 1(IGF 1) was stained using immunohistochemical techniques.We also measured the neointima areas?lumen areas?media areas and the percentage of NF κB?IGF 1 positive areas by computer analysis of photomicrographs.Results Strong neointimal proliferation and strait lumen were observed in the control group.There werent obvious changes in 9 1Gy group;In 21 8Gy group,the proliferation and migration of smooth muscle cells was significantly suppressed and the lumen areas did not decrease;however the neointima thicked to make the cavity obvious stenosis,and the smooth in media was shrinked and thinned in 33.4Gy group,four vessels occurred arterial thrombosis.Conclusions Endovascular brachytherapy with 32 P filled ballon catheter system could prevent restenosis after angioplasty,the mechanism may be due to reduce neointima formation and increase lumen size;inhibit the activation of NF κB and its target gene,which reduce the proliferation and migration of smooth muscle cells;increase apoptosis and improve the vascular remodeling.