肝内门腔分流术支架与血管支架组织成分的对比研究

Experimental comparison study of the tissue characteristics in transjugular intrahepatic portosystemic shunt and vascular stent

目的对比研究经猪颈静脉肝内门腔分流术（TIPS）与血管支架术后组织成分的异同，为TIPS与血管支架再狭窄的形成机制及防治提供更多的信息。方法对6只25kg的家猪进行TIPS术，建立TIPS猪模型，并行髂静脉支架置入术。14—28d后处死，取出肝脏TIPS组织及支架段静脉组织做病理检查，包括大体标本检查、电镜检查，病理切片行HE染色，免疫组织化学（简称免疫组化）分析抗平滑肌肌动蛋白-α、细胞增殖核抗原（PCNA）、波形蛋白、肌球蛋白表达，蛋白印迹（Westernblot）分析转化生长因子-β（TGF—β）表达。将TIPS组织与血管支架组织进行上述多项指标的对比分析。所获数据进行Kruskal Wallis秩和检验。结果动物处死时，6只猪有4只TIPS通道出现不同程度再狭窄，其中有2只TIPS通道完全堵塞，而髂静脉支架置入术后静脉支架均通畅，仅见支架通道内壁为一薄层内膜组织覆盖，腔内无狭窄。电镜检查，TIPS再狭窄组织较为稀疏，较多胶原基质与纤维，细胞成分少至中等量，细胞形态多样且不规则，可见平滑肌细胞、少量成纤维细胞及成肌纤维细胞，细胞含丰富分泌颗粒；TIPS支架通畅组织可见大量胶原纤维，含中等量的细胞成分，主要是成纤维细胞及平滑肌细胞，细胞器基本正常。支架段静脉组织含大量胶原纤维，细胞成分较多，主要为成纤维细胞，平滑肌细胞较少。免疫组化检测：抗平滑肌肌动蛋白-α，TIPS再狭窄组织表达强阳性，TIPS通畅组织表达也较强，支架段静脉组织表达较强，但阳性细胞明显稀疏；PCNA在TIPS再狭窄组织表达强阳性，在TIPS通畅组织表达也较强，在支架段静脉组织表达明显较弱；波形蛋白在支架段静脉组织表达较强，在通畅的TIPS支架通道组织中为阳性表达，而在TIPS支架再狭窄组织中表达减弱；肌球蛋白在’nPS再狭窄组织表达为弱阳性，而在TIPS通畅的支架组织与支架段静脉组织表达更弱。Westernblot检测TGF—β，支架段静脉组织、正常静脉组织对照、正常肝组织对照、TIPS狭窄组织及TIPS通畅组织的吸光度比值（TGF-β/β肌动蛋白）中位数分别为0．23、0、0、0．57、0．30，对所获条带的光密度比值进行统计学分析，差异有统计学意义（H=27．8，P〈0．01）。结论猪模型中，TIPS再狭窄组织中主要为抗平滑肌肌动蛋白-α阳性的平滑肌细胞增殖，细胞增殖迁移能力强，细胞型稳定性低；通畅的TIPS组织与支架段静脉组织相似，表达波形蛋白的成纤维细胞较多，细胞较稳定。

Objective To investigate the tissue characteristics within vascular stent and transjugular intrahepatic portosystemic shunt（TIPS） on swine and to provide more information for the understanding and prevention of vascular stent and TIPS restenosis. Methods Animal models for TIPS were built in 6 swine and vascular stents were implanted in iliac veins simuhaneouly. 14--28 days after the operation, the 6 swine were killed to remove the TIPS and vascular stent and the pathological examinations were performed on the tissues within the shunt and stent. The similarities and differences of the tissues within the shunt and stent were analyzed with Kruskal Wallis test. Results Restenosis of TIPS occurred in 4 models and complete occlusion were seen in 2, while all vascular stents were patent and coated with a thin layer of intimal tissue. Electron microscopic results showed that the tissues in restenotic TIPS were loose and with more extra matrix and fibers, and less smooth muscle, fibroblastic and myofibroblastic cells with different and irregular shape and rich secretory granules. The tissues in patent TIPS contained more extra fibers, smooth muscle and fibroblastic ceils with normal organelle. The intimal tissues in vascular stent contained more fibers and fibroblasts cells, less smooth muscle cells. On immunohistochemical staining, the tissues in restenotic and patent TIPS as well as the intimal tissues in vascular stent had strong positive expression for anti-SMC- actin-α, the expression were gradually weakened for PCNA, the intimal tissues in vascular stent had a strong positive expression for vimentin, while the expression of the tissues in restenotic and patent TIPS were weakened gradually. For myoglobulin, the tissues in restenotic TIPS had weakly positive expression, the expression in patent TIPS and vascular stent were almost negative. Western blot results for TGF-β showed that the absorbance ratios of the intima tissues in vascular stent, normal vascular tissues, normal liver tissues, the tissues in restenotic and patent TIPS were 0. 23, 0, 0, 0. 57 and 0. 30 respectively, and they were significantly different （ H = 27. 8, P 〈 0. 01 ）. Conclusions The tissues in restenotic TIPS mainly contain proliferated SMCs which have positive expression for anti-SMC-actin-α, strong proliferation and movement but unstability. The tissues in patent TIPS and intimal tissues in vascular stent mainly contain fibroblastic cells which have positive expression for vimentin and stability.