腹主动脉人工血管置换术后放疗对人工血管内膜的影响

Effect of radiotherapy on neointima of prosthetic vascular graft after prosthetic vessel replacement of abdominal aorta

目的观察腹主动脉人工血管置换术后35Gy体外分割放疗对人工血管通畅率、内膜增生及血管内皮细胞(VEC)覆盖的影响。方法对20只犬行腹主动脉膨体聚四氟乙烯(ePTFE)人工血管置换术。术后动物分成对照组和放疗组,每组10只。两组均于术后4,8周采集标本,行HE染色,增殖细胞核抗原(PCNA)及分化抗原簇34(CD34)免疫组化检测。结果两组术后各有1例人工血管内血栓形成,通畅率均为90.0%。术后4周,放疗组和对照组人工血管内膜形成完整,内膜厚度和PCNA表达差异无统计学意义(均P>0.05),VEC覆盖均不完全;术后8周,放疗组内膜厚度较对照组明显变薄(P<0.05),对照组人工血管近端、中间、远端3处内膜厚度分别为(72.30±9.15)μm,(40.46±7.75)μm和(98.06±6.90)μm,放疗组人工血管近端、中间、远端3处内膜厚度分别为(37.67±6.77)μm,(21.16±4.98)μm和(56.64±5.13)μm,PCNA表达减少(P<0.05);VEC均覆盖完整。结论腹主动脉人工血管术置换后35Gy体外分割放疗不影响移植人工血管通畅率,对内膜VEC的覆盖亦无明显影响,但可抑制人工血管内膜增生和PCNA的表达。

Objective To observe the effect of external segmental irradiation at a total dose of 35 Gy after prosthetic vessel replacement of abdominal aorta on the patency rate, the neointima proliferation and the covering of vascular endothelial cell of the vascular graft. Methods Prosthetic vessel replacement of abdominal aorta with ePTFE vascular graft was done in 20 mistus dogs, which were divided into control group and radiotherapy group, 10 dogs respectively, The specimen in each group were harvested at 4 weeks and 8 weeks after surgery. H-E staining, immunohistochemistry test of PCNA and CD34 were done, Results There was 1 case in each group with thrombosis in prosthetic vascular graft, and the patency rate was 90% in each group. Four weeks after surgery, the neointima of prosthetic vascular graft was formed completely in each group, and the intimal thickness or the PCNA expression had no statistically difference （ P 〉 0.05 ） between the radiotherapy and control groups, and the coverage of vascular endothelial cell was incomplete in each group; 8 weeks after surgery, the intimal thickness of radiotherapy group was statistically thinner than that of control group （ P 〈 0. 05 ） , and the intimal thickness of vascular graft in control group at the proximal, middle, and distal segment was： （72.30 ±9. 15）μm, （40.46 ±7.75）μm and （98.06 ± 6.90） μm respectively, and that in radiotherapy group was： （37.67 ± 6.77 ） μm, （21. 16 ± 4.98 ） μm and （56.64 ± 5. 13 ） μm respectively. The PCNA expression was statistically less in radiotherapy group than that in control group （ P 〈 0. 05 ） . The vascular endothelial cell coverage was complete in each group. Conclusions The external segmental radiotherapy at a total dose of 35 Gy after prosthetic vessel replacement of abdominal aorta does not affect the patency rate of prosthetic vascular graft, and not significantily affect the vascular endothelial cell coverage, but it can inhibit the neointima proliferation and PCNA expression.