术前放疗对犬腹主动脉和下腔静脉人工血管置换术后人工血管内膜的影响

Effect of preoperative irradiation on neointima of the ePTFE blood vessel prosthesis in dogs

目的观察术前放疗对犬腹主动脉、下腔静脉人工血管置换术后人工血管内膜的影响。方法杂种犬18只,随机分为放疗组和对照组各9只。放疗组对标记的拟行人工血管移植的血管区行分割放疗,6周后于肾动脉下腹主动脉、下腔静脉行ePTFE人工血管置换术,4周后取标本。对照组除不放疗外各项操作同放疗组。观察两组动物人工血管的通畅率,并行HE染色和免疫组化PCNA和CD34染色。结果放疗组有2犬术后当天死亡,对照组全部存活。放疗组术后3条静脉人工血管完全堵塞,对照组2条完全堵塞,两者差异无统计学意义(P>0.05)。两组动脉人工血管均通畅,内膜完整,但内皮细胞覆盖不完全。放疗组的吻合口近、远端处CD34阳性细胞数差异无统计学意义,而在人工血管中部放疗组低于对照组(P<0.05);放疗组吻合口近、远端及人工血管中部内膜厚度均较对照组薄(P<0.05);而放疗组3个点PCNA阳性细胞表达较对照组为低(P<0.05)。结论术前放疗对人工血管置换术后4周内膜的增生有抑制作用,不会降低其通畅率。

Objective To observe the effect of fractionated preoperative irradiation on neointima of the replaced ePTFE blood vessel prosthesis in dogs. Methods Eigteen mongrel dogs were equally divided into irradiated group and control group at radom according to whether or not preoperative irradiation was given. Six weeks after preoperative irradiation, subrenal abdominal aorta and inferior vena cava of the irradiated group were replaced by ePTFE blood vessel prosthesis. Specimens were harvested at 4 weeks after operation, and H-E staining, immunohistochemistry test of PCNA and CD34 were done. Results Two dogs died after operation. Three grafts implanted into IVC in irradiated group and 2 in control group were completely occluded, but no graft was obstructed in AA. The neointima of vascular graft formed completely, but the coverage of vascular endothelial cells was incomplete in both groups. The expression of CD34 of irradiated group was statistically less than control group in the middle of the graft （ P 〈 0.05 ） , while there were no statistical difference at the distal and proximal anastomosis. The intimal thickness in distal, proximal and middle of the graft was thinner in irradiated group than that in control group （ P 〈 0. 05 ）. The PCNA proliferation in irradiated group was lower than in control group （ P 〈 0. 05 ）. Conclusions Fractionated preoperative irradiation showed inhibition of the intima hyperplasia 4 weeks after vessels replacement and has no negative effect in patency of graft both in veins and aortas.