脑动静脉畸形经立体定向放射治疗后不同时期的组织病理变化

Histopathology of Cerebral Arteriovenous Malformations after Stereotactic Radiotherapy in Different Periods

目的研究脑动静脉畸形(AVMs)经立体定向放射治疗后不同时期的组织病理变化。方法对10例脑AVMs立体定向放射治疗后的病理标本进行苏木精-伊红染色,并用平滑肌肌动蛋白(SMA)、血管内皮生长因子(VEGF)及神经胶质酸性蛋白等抗体进行免疫组化研究。结果经立体定向放射治疗后,早期脑AVMs血管病理变化包括内膜层与血管壁分离,细胞外基质增生;中期可见平滑肌细胞增生,血管壁增厚,管腔狭窄至消失,管壁玻璃样变;晚期病理变化包括血管壁进行性增厚,在完全玻璃样变的区域细胞核固缩。早期放射反应的动脉管壁中VEGF呈阳性表达,在中期放射反应的动脉管壁中SMA呈强阳性表达。结论立体定向放射治疗后脑AVMs血管中层的平滑肌细胞增生和变性是血管闭塞的关键因素。

Aim To study the histopathological changes of cerebral arteriovenous malformations （AVMs） after stereotactic radiotherapy. Methods Ten surgical specimens previously treated by stereotactic radiotherapy were analyzed by hematoxylin eosin （HE） stain and immunohistochemistry assay. The monoclonal antibody smooth muscle actin （SMA）, vascular endothelial growing factor （VEGF） and glial fibrillary acidic protein （GFAP） were used for immunochemistry stain. Results The earliest changes after gamma knife irradiation appeared to be damaged to endothelial cells followed by elaboration an extracellular matrix of the intimal layer. Progressive angiopathological changes including proliferation of smooth-muscle cells, thickening and hyalinization of the vessel wall, narrowing or obliteration of the lumen could be observed. Finally, nuclear condensation and hyaline transformation occurred. VEGF expression appeared in the wall of early radio-effect artery. SMA was strongly expressed in the arterial wall of the middle period. Conclusion Stereotactic radiosurgery of AVMs cause the proliferation of smooth-muscle cells, which might be the key factor led to progressive stenosis and obliteration of the cerebral AVMs.