组织蛋白酶B在人颅内动脉瘤瘤壁的表达及意义

The expression and role of Cathepin B in intracranial aneurysm wall

目的观察组织蛋白酶B（CatB）在颅内动瘤内的表达情况，评估其对瘤壁血管平滑肌细胞凋亡的作用，以此揭示颅内动脉瘤可能形成的机制。方法以2006年11月至2009年2月的20例显微手术切除的颅内动脉瘤标本为研究对象，取脑外伤后内减压术切除的正常脑皮层动脉血管6例作为对照，通过透射电镜了解其超微结构变化；应用免疫组化的方法检测标本中CatB、仪平滑肌激动蛋白（α-SMA）和半胱天冬酶-3（Caspase-3）的表达，并对染色强度进行分级；通过Real—timePCR的方法检测标本内的CatBmRNA表达。结果（1）免疫组化结果：动脉瘤组CatB、Caspase-3表达指数高于对照组，而动脉瘤组α-SMA表达低于对照组（P〈0．05）；CatB与Caspase-3、α-SMA及动脉瘤的大小具有相关性（P〈0．01）。（2）Real—timePCR：CatBmRNA在颅内动脉瘤的表达为对照组的3．8倍（P〈0．01）。（3）透射电镜的观察：动脉瘤瘤壁血管平滑肌细胞明显减少，基质纤维断裂消失；部分血管平滑肌细胞核内见染色体边聚，核固缩，并有胞浆或胞核部分脱落或裂解成碎片，还有部分瘤壁可见典型的凋亡小体。结论CatB可能参与了颅内动脉瘤的形成与生长。

Objectives To detect the expression of Cathepin B（CatB） in the intracrauial aneurysm wall and its effect to the apoptosis of vascular smooth muscle cells, aimed at clarifying the pathological formation mechanism of intracranial aneurysm. Methods From November 2006 to Februry 2009, 20 intracranial aneurysm samples were collected as the experimental group, and 6 cases of normal pallium artery samples were collected as the control group. Immunohistochemical technique was used to evaluate the expressions of CatB, a-smooth muscle actin （a-SMA） and Caspase-3. The expression of CatB mRNA was evaluated by real-time PCR. The ultrastructure of intracranial aneurysms were observed by using the transmission electronic microscope. Results Compared with the normal pallium artery specimens, the expression of CatB and Caspase-3 both significantly increased in the intracranial aneurysm walls where α-SMA decreased（P 〈0. 05 ）. The mean expression of CatB mRNA in intracranial aneurysm samples was about 3.8-folds than that in control group （ P 〈 0.01 ）. There were excessive apoptotic vascular smooth muscle cells （VSMCs） in the tunica median,and typical apoptotic body were observed in some aneurysm walls. Conclusion Cathepin B may be involved in the formation and the progression of intracranial aneurysm.