Endovascular Brachytherapy With Liquid ～(188)Re To Inhibit Neointimal Hyperplasia Of Common Carotid Artery In Rabbits

[Objective]:Endovascular brachytherapy to lesion after intervention is a new method of preventing from restenosis . The mechanism of endovascular irradiation, the optimal radioisotope, the means, and the required lowest dosage to restenosis are unresolved. The mainly beta-emitter liquid Rhenium-188(188Re) is a prospective isotope with allowing intravascular irradiation by a conventional balloon catheter without the problem of centering the radiation source causing by the other means. In an experimental model of restenosis by overstretch injury, the suppressing effect on intimal hyperplasia , the possible mechanism and the feasibility of endovascular brachytherapy were investigated. [Method]:After being overstretched the right common carotid arteries by3.5x20mm balloon, twenty New Zealand White rabbits were randomized into irradiation (n=10)and control group(n=10). Endovascular bachytherapy was performed wth a 188Re filled 3. 0x20mm balloon catheter delivering an assuming dosage of 16Gy(0.5mm underneath the luminal surface) in the irradiation group, whereas isovolume normal sodium filled balloon catheter was used in the control group for a equal period. Then thirty days after the overstretching angioplasty, the animals were killed and the vessels were excised. The histological and immunohistochemical results were analyzed. [Results]:The intimal area in the irradiaton group was significantly different from the control group(0. 15 ± 0.05mm2 vs 0. 44±0. 07mm2) ;The positive staining index of proliferation cellular nuclear antigen(PCNA), transforming growth factor(TGF) and RAM-11(macrophage antigen) in the irradiation group was significantly smaller than that in the control group(0. 028±0. 005 vs 0. 054±0. 011, 0. 033 ± 0. 008vs0. 063 ±0. 014, 0. 022 ± 0. 009vs0. 037 ± 0. 010, respectively) ;T he positive staining of a -actin index in intima was no difference between the irradiatin group and the control group ; The staining of leukocye common antigen(LCA) was negative in both group;The positive staining index of von Willebrand factor(vWF) in the irraditon group was also significantly different from that in the control group(0. 011±0. 002 vs 0. 024 ± 0. 007). [Conclusion]:Conventional balloon catheter transmittedendovascular brachytherapy with liquid 188Re after interventional procedure is feasible and effective on inhibitting neointimal hyperplasia. The preventive effect on restenosis is possibly achieved by suppression of cellular proliferation, macrophage migration, and cytokine secretion. The role of leukocye in restenosis and intravacular therapy is unclear.The re-endothelization is delayed by endovascularbrachytherapy. Aneurysm is not found.The effect on fibrosis withendovascular brachytherapy is unclear.