内皮损伤参与兔脑动脉瘤形成的研究

Involvement of endotheliun injury in brain aneurysm formation in rabbits

目的观察结扎新西兰大白兔双侧颈总动脉导致基底动脉分叉处动脉瘤的形成，探讨该过程中动脉分叉处内皮细胞的形态和功能变化。方法将15只新西兰大白兔分成实验组和对照组。实验组大白兔结扎双侧颈总动脉代偿性地提高基底动脉的血流，对照组行假手术。在结扎颈总动脉后的3个月内，通过多普勒监测基底动脉的血流。1．5、3个月后，获取兔基底动脉分叉部，采用电子显微镜和免疫组织化学的方法观察分叉部内皮细胞的形态和功能。结果在第1次手术后的0、1、4、7、14、28、35、42、49、56、70、84d后，采用多普勒测量观察到实验组基底动脉血流量较对照组显著增加。在实验组中，首次结扎的1．5个月后，β—eatenin仅表达在内皮细胞核，3个月后，在兔的基底动脉分叉处出现动脉瘤的早期阶段，并未见有β—catenin的表达。电镜下观察到结扎的1．5个月后的内皮细胞由梭形变成柱形，3个月后内皮细胞间出现裂缝，并出现细胞核边集。结论内皮细胞的损伤诱发了脑动脉瘤的形成。

Objective To investigates the morphological and function changes of the endothelial cells at the rabbit basilar bifurcation in response to sustained high blood flow after bilateral common carotid artery ligation. Methods Fifteen adult female New Zealand white rabbits were randomly divided into experimental group and sham control group. The rabbits in experiment group were subjected to bilateral common carotid artery ligation to increase the compensatory basilar artery flow, and those in control group got sham operation. Basilar artery flow was monitored by transcranial Doppler within 3 months after surgery. Basilar artery bifurcation tissues were harvested at 1.5,3 months after bilateral common carotid artery ligation respectively. The endothelial cells of basilar artery bifurcation were examined morphologically by using electron microscopy and immunohistocbemically by using antibodies against 13-catenin. Results On the day 0,1,4,7,14,28,35,42,49,56,70, and 84 after the first sugery, it was found that the basilar artery blood flow in experimental group was significantly increased as compared with sham control group. In experimental group,after 1.5 months, the β-catenin was mainly expressed on the nuclei, and after 3 months, the early stage of aneurysm formation on the basilar artery bifurcation appeared, but no expression of β-catenin was detected. Under the scanning electron microscopy,the endothelial cells were changed to column aspect from fusiform at 1.5 months, and there were cracks between endothelial cells and endothelial cell nucleus margination. Conclusion By observing the endothelial cells changes at basilar artery bifurcation in response to sustained high blood flow in this rabbit model, it was suggested that the impairment of endothelial ceils may initiate aneurysm formation.