An Experimental Study on the Effects of Endovascular Irradiation Using Liquid ~(32)p-filled Ballon Catheter on Vascular Cell Proliferation and α-SM Actin Expression after Interventional Therapy

Objective To evaluate the effects and possible mechanism of endovascular irradiation using liquid 32 P-filled ballon catheter on restenosis after interventional therapy.Methods 54 Wistar rats were randomly divided into injured group, which received the balloon injury of thoracic aorta, and irradiated group, which received the balloon injury of thoracic aorta followed immediately by ionizing radiation using 20 Gy or 28 Gy liquid 32 p-filled balloon catheter. The expressions of proliferation cellular nuclear antigen(PCNA) in vascular cells and smooth muscle actin(α-SM actin) in the vascular adventitia were detected by immunohistochemical method, and were quantified by computer image analysis. The morphologic changes of thoracic aorta were analyzed by computer image analysis . Results ⑴14 days after injury, both the lumen area and external elastic lamina (EEL) area of thoracic aorta in the irradiated group were significantly larger than those in injuried group, but the neointima area was significantly smaller in the irradiated group. The above chanages were negative relation with the irradiation doses. ⑵At third day after injury, the cell proliferation activity in the adventitia and media of thoracic aorta in the irradiated group obviously decreased in dose dependent manner compared with the injured group. At the 7th day after injury,there was not significant difference in the cell proliferation in the adventitia and media of the vessels between the irradiated group and injury group. ⑶At 7th and 14th days after injury. The α-SM actin expression level in the adventitia of thoracic aorta in the irradiated group was significantly lower than that in the injured group, which was negatively related with the irradiation dose.Conclusion To some extent, there was a correlation between the irradiation dose of using liquid 32 p-filled balloon catheter and the areas of lumen, EEL and neointima. The endovascular irradiation could contribute to inhibiting the neointima and improving the vascular remodeling by inhibiting vascular cell proliferation and adventititial α-SM actin expression.