线粒体途径介导的细胞凋亡在兔颅内动脉瘤生成中的作用

Roles of mitochondrial pathway-mediated apoptosis in intracranial aneurysm initiation in rabbits

目的探讨线粒体途径介导的细胞凋亡参与颅内动脉瘤生成的分子机制。方法取新西兰大白兔15只,用计算机随机法分为3组,采用双侧颈动脉结扎术造模基底动脉瘤后,分为造模后2 d组3只、造模后7 d组6只[其中3只用于实时荧光定量聚合酶链反应(PCR)分析],假手术组6只(其中3只用于实时荧光定量PCR分析)。获取动物基底动脉尖组织,观察血管壁的组织病理变化情况,用TUNEL法检测凋亡细胞,免疫组化染色及定量分析炎性细胞分布,实时荧光定量PCR方法检测凋亡相关蛋白mRNA的表达情况。结果 (1)造模后2、7 d组兔基底动脉尖部,即内弹力层损害部位均发现凋亡细胞,造模后2 d组凋亡细胞数量[(4.02±0.21)个]明显高于基底动脉主干[(0.40±0.13)个]、左侧大脑后动脉[(0.41±0.22)个]和右侧大脑后动脉[(0.29±0.11)个],差异有统计学意义(均P<0.05)。造模后7 d组基底动脉尖部凋亡细胞数量[(5.01±0.29)个]明显高于基底动脉主干[(0.49±0.21)个]、左侧大脑后动脉[(0.31±0.12)个]和右侧大脑后动脉[(0.41±0.19)个](均P<0.05)。而在假手术组兔未观察到内弹力层损害及凋亡细胞。(2)造模后7 d组兔基底动脉尖部半胱天冬氨酸酶9(caspase-9)mRNA表达(1.97±0.23)及caspase-3 mRNA表达(2.31±0.40)较假手术组均明显增高(P<0.01)。结论细胞凋亡参与了单纯血流动力学诱导的基底动脉尖部动脉瘤的早期生成,其分子发生机制是通过caspase-9激活由BCL-2介导的线粒体途径。

Objective Toinvestigatethemolecularmechanismsofmitochondrialpathway-mediated apoptosisinintracranialaneurysminitiationinrabbits.Methods FifteenNewZealandwhiterabbitswere divided into 3 groups using the computer random method. After using bilateral carotid artery ligation for modeling basilar artery aneurysm,they were divided into a 2-day group （n=3）,a 7-day group （n=6）（3 of them were used for real-time quantitative polymerase chain reaction [PCR]analysis）,and a sham operation group （n=6）（3 of them were used for real-time quantitative PCR analysis）. The tissue of apex of basilar artery was harvested and the histopathological changes in the vascular wall were observed. TUNEL staining was used to detect apoptotic cells and immunohistochemical staining,and quantitative analysis was used to analyze inflammatory cell distribution. Real-time quantitative PCR was used to detect the expression of apoptosis-related protein mRNA. Results （1 ）After modeling,the apoptotic cells were found at the apex of basilar artery in rabbits （the site of internal elastic layer lesion ）of the 2-day group and 7-day＆amp;nbsp;group. In the 2-day group after operation,the numbers of apoptotic cells （4. 02 ± 0. 21）were significantly higher than those of the basilar artery trunk （0. 40 ± 0. 13）,the left posterior cerebral artery （0. 41 ± 0.22）,and the right posterior cerebral artery （0. 29 ± 0. 11）. The differences were statistically significant （P〈0. 05）. After modeling,the numbers of apoptotic cells （5. 01 ± 0. 29）of the 7-day group were significantly higher than those of the basilar artery trunk （0. 49 ± 0. 21）,the left posterior cerebral artery （0. 31 ± 0. 12）,and the right posterior cerebral artery （0. 41 ± 0. 19）（P〈0. 05）. The internal elastic layer lesions and apoptotic cells were not observed in the rabbits of the sham operation group. （2）After modeling, the expression levels of caspase 9 （1. 97 ± 0. 23）and caspase-3 mRNA （2. 31 ± 0. 40）at the apex of basilar artery in rabbits of the 7-day group were increased significantly compared with that of the sham group （P〈0.01）.Conclusion Apoptosisisinvolvedintheearlyprocessofaneurysmsinsimple hemodynamics-induced basilar terminus aneurysm formation. Its molecular mechanisms are activated by Bcl-2-mediated mitochondrial pathway through caspase-9.