β射线局部照射预防自体移植静脉内膜增生的实验研究

目的：研究放射性同位素局部照射对自体移植静脉段内膜增生反应的影响及其可能机理。方法：建立40只大鼠自体静脉移植模型，随机分成对照组（单纯自体静脉移植组），8，18，36Gy组（按不同32P内膜照射剂量），每组10只，2周后取材固定，行HE染色，Verhoeff弹力纤维染色，增殖细胞核抗原（PCNA）免疫组化测定（SP法），计算机图像分析仪测量移植血管内膜厚度。结果：移植静脉段的内膜平均厚度：对照组与8Gy组差异无显著性（P＞0．05），但高于18，36，Gy组（P＜0．05），18Gy组与36Gy组间差异无显著性（P＞0．05），PCNA阳性片示，18，36Gy组VSMC增殖较对照组受到明显抑制（P＜0．01），两组差异无显著性（P＞0．05），8Gy组较对照组差异无显著性（P＞0．05），结论：适当剂量β射线局部照射可以抑制自体移植静脉的内膜增生及平滑肌细胞（SMC）的增殖，减少再狭窄的发生。

Beta irradiation inhibits neointimal formation in vein grafts

Objective The study was to evaluate the effect of beta irradiation on intimal proliferation response in vein grafts. Methods An autogenous vein graft model was established in 40 rats by transplanting internal branch of jugular vein to carotid artery by end|to|end anastomosis.The vein was irradiated by 32 P before anastomosis.Four dose schedules were studied:(1) control graft(nonirradiated);(2) irradiated with 8 Gy;(3) 18 Gy;and (4) 36 Gy.The grafted veins were harvested at 2 weeks after the operation.IH (intimal hyperplasia) and SMC (smooth muscle cell) proliferation were histologically and immunohistochemically observed and analyzed by a computer digitalizing system. Results In 18 Gy and 36 Gy |irradiated grafts compared with the control,there was a significant decrease in the average intimal thickness ( P <0 05).There was no significant difference between the two irradiation groups ( P >0 05).Immunohistochemical analysis of PCNA indicated decrease of positive cells in both 18 Gy and 36 Gy groups compared with 8 Gy and the control group ( P <0 01).There was no significant difference between 18 Gy and 36 Gy ( P >0 05) groups,and there was also no significant difference between 8 Gy and the control group ( P >0 05). Conclusion These preliminary results demonstrate that proper dose of beta irradiation in vein graft inhibits smooth muscle cells proliferation and neointimal hyperplasia in rat.;