Objective: To investigate the effect of intravascular in radiation on thearterial wall smooth muscle cells (SMCs) proliferation and apoptosis after iliac artery bollominjury in figs. Methods: Twenty-seven miniature figs were divided into three groups. All pigsunderwent iliac artery balloon over-stretch. An^(192) Ir source through afterloader was positionedat the injuried segments to give 10 Gy in 9 pigs and 20 Gy in the other 9 pigs, and the rest 9 pigswere, used as control group. The pigs were killed on the 3rd, 10th and 28th days respectively forobservation. The injured segments were processed to examine SMCs proliferation by proliferation cellnuclear antigen (PCNA) and apopto-sis by terminal deoxynucleotidyl transferase-mediated dUTPnick-end labeling (TUNEL). Results: PC-NA index analysis has some that SMCs proliferation inneointima was significantly inhibited in irradiation group on the 10th and 28th days. The value forintimal SMCs apoptosis in control vs 10 Gy and 20 Gy irradiation groups were: (1. 185+-0. 49)% vs(2. 27+-0. 49)%(P>0. 05) and (1. 85+-0. 49)% vs (2. 53+-0. 45)%(P<0. 05), at the 10th day; (1.61+-0. 35)% vs (3. 11+-0. 51)%(P<0. 05), and (1.61+-0. 35)% vs (7. 05+-1. 82)% (P<0. 05), on the28th day. In irradiated arteries, the maximal incidence of intimal SMCs apoptosis was (7. 05+--1.82)% in 20 Gy group vs (3. 11+-0. 51)% in 10 Gy group (P<0. 05), on the 28th day. In the same doseirradiation group, the incidence of intimal SMCs apoptosis was higher on the 28th day than that onthe 10th day. Conclusion: Intra-arterial gamma irradiation can inhibit intimal SMCs proliferationand stimulate SMCs apoptosis in balloon-in jured arteries. These may be contributive to preventionof restenosis of arteries after balloon injury.
