External Beam Irradiation Prevents Vessel Restenosis In A Rabbit Restenosis Model

Percutaneous transluminal coronary angioplasty (PICA) is the major method of treating arteriosclerosis vascular disease; it serves for the patients of coronary stricture. Carotid endarterectomy was generally acknowledged with the most utility method of prevention cerebral infarction, especially for Severe constriction patients. However, 30%~50% patients have restenosis after treatment. So these treatment methods was localized under these conditions. Finding and establishing a efficiency method to decrease the restenosis incidence rate could expand the coverage of these treatment methods, and improve their curative effect.Three parts in this study: ?Establish a animal model of vessel restenosis. (2) Investigate the mechanism for the occurrenc and developing of restenosis. (3) Investigate the role of external irradiation to restenosis and the mechanism of the role.In the study, we established the rabbit restenosis model under the carotid endarterectomy. This model is stable, utility, efficiency and has low mortality rate, further more has no relative reports in country and overseas. Through the investigation, we definitude the material of vessel restenosis is vessel media smooth muscle cell (SMC), its proliferation, migration and phenotypic conversion causes the restenosis. The Aggregation blood platelet at injury vessel excretive the platelet derived growth factor (PDGF), and the inflammation cell Infiltrating in adventitia release the activate cytokine, and that proliferate SMC autocrine and paracrine role, these factor's co-operation was the power of SMC proliferation, migration and phenotypic conversion. Through the investigation, we definitude the external irradiation could prevent the vessel restenosis, and certificate the prevention role was process through two ways: ?The blood platelet is irradiation resistance, it aggregate and release a series of activate material (exp.PDGF) which can not be destroy by irradiation, however, the recipient cell of these activate material, smooth muscle cell is irradiation sensitive after be activated. Irradiation inhibit the proliferation, migration and phenotypic conversion activity of activate smooth muscle, so inhibit the neointimal proliferation. (2) Monocyte and macrophage are irradiation sensitive, and its activity were easily inhibited by irradiation, so the amount of the activity factors secreted by monocytes and marophages were reduce or disappear.Suitability dose of irradiation could inhibit the occurrenc and developing of resenosis. The stereotactic radiotherapy that conquers the disadvantage of conventional external irradiation could localize precisely, and the dose distribution was better than vascular brachytherapy. The stereotactic radiotherapy is a new method of treating vessel resenosis, is the supporter of interventional radiology, neurosurgery and transplantation.