[The role of beta irradiation on neointimal formation and apoptosis in vein grafts model].
OBJECTIVE
To evaluate the effect of beta irradiation on intimal proliferation and apoptosis in vein grafts.


METHODS
Autogenous vein graft model was established in 80 rats by transplanting the internal branch of the jugular vein to the carotid artery by end to end anastomosis. The veins were irradiated by (32)P solution before anastomosis. Two dose schedules were studied: control group (graft, nonirradiated) and radiation group (20 Gy). The grafted veins were harvested at 3, 1, 2 and 4 week respectively after the operation. intimal hyperplasia (IH), smooth muscle cell (SMC), proliferation, p53, bcl-2 and bax were observed pathologically and immunohistochemically. They were analyzed by a computerized system. The presence of apoptotic VSMC was demonstrated by TUNEL method.


RESULTS
There was a significant decrease in the average intimal thickness at 7, 14 and 28 days (t = 15.694, P < 0.05) in the radiation group. Immunohistochemical analysis of PCNA indicated decreased positive cells in the radiation group compared with the controls at 1 and 2 weeks (t = 60.157, P < 0.01). Apoptosis of VSMC was higher in the radiation group than in the control group at 2 weeks (t = 56.176, P < 0.01). There was no significant difference in expression of P(53) between the two groups, and there was a significant increase in bax/bcl-2 in the radiation group at 2 weeks (t = 9.783, P < 0.05).


CONCLUSIONS
These preliminary results demonstrated that low dose of beta irradiation in the vein graft inhibits SMC proliferation and induces the apoptosis of VSMC in rats.
Lang
Xiaoou
X
Department of General Surgery, First Clinical College, Chinese Medical University, Shenyang 110001, China.
Li
Jun
J
Zeng
Ke
K
Dai
Zhi
Z
Ma
Wenfeng
W
Zhang
Qiang
Q
Duan
Zhiquan
Z
D000818:Animals; D017209:Apoptosis; D001610:Beta Particles; D001918:Brachytherapy; D004195:Disease Models, Animal; D006083:Graft Occlusion, Vascular / Q000378:metabolism / Q000473:pathology*; D020287:In Situ Nick-End Labeling; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000473:pathology / Q000528:radiation effects; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism; D051381:Rats; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D017539:Tunica Intima / Q000473:pathology / Q000528:radiation effects*
D018809:Proliferating Cell Nuclear Antigen; D016159:Tumor Suppressor Protein p53