Experimental study of endovascular irradiation preventing restenosis after angioplasty

Objective To observe the dose effect relation of endovascular brachytherapy using radioactive liquid filled balloon and restenosis after angioplasty and to investigate the possible mechanism of irradiation therapy preventing restenosis. Methods After balloon dilating injury of rabbit iliac arteries, the 4 experimental groups were administered 32 P brachytherapy, the absorbed doses were 3, 9, 18 and 36 Gy, respectively. For the control groups the balloons were filled with normal saline. Pathological sections of iliac arteries at different end points were studied by means of HE staining, proliferating cell nuclear antigen (PCNA) immunohistochemical staining and electron microscopy. We also measured the lumen areas and neointima areas by computer analysis of photomicrographs. Results Strong neointimal proliferation and strait lumen were observed in the control group. In 18 Gy group, the proliferation of smooth muscle cells was obviously suppressed, cell apoptosis increased, and the lumen area did not decrease. Arterial thrombosis occurred in 36 Gy group. There weren't obvious changes in 3 and 9 Gy groups. Conclusions Endovascular brachytherapy using 32 P filled balloon catheter system can prevent restenosis after angioplasty. The mechanism might be the inhibition on the proliferation of smooth muscle cells, increase in apoptosis and improvement of vascular remodeling.