猴新型颅内动脉瘤模型构建及诱导巨噬细胞减少下调MMPs表达和明胶酶活性影响猴早期颅内动脉瘤形成的机制研究

Inflammation has been proven to be one of the major pathological mechanisms causing intracranial aneurysm (IA). However, mechanisms of initiation and progression of IA have not yet been fully understood. Animal experiment also found that macrophages accumulated in the luminal surface of the endothelium in aneurysmal walls, and may be the source of the matrix metalloproteinases (MMPs). Whether MMPs secreting mediated by macrophages was one of the major pathological factors of the progression of IA is unknown. In the present study, animal models of IA were usually established using a variety of physiologic and pathologic manipulations, such as carotid ligation, elastase-induced, et al. Nevertheless, all of these methods have a weakness in the aspect of naturally occurring IA. Besides, laboratory animals were distinguished with human beings in the aspect of vessel morphous, fibronolysis, living habit, et al., which limited the model accuracy and feasibility. In this regard, we originally established the late cynomolgus IA model using a combination of a single injection of elastase into the cerebrospinal fluid and angiotensin II-induced hypertension in the assistance of the atherogenic diet. We want to investigate the significance of induced lacking macrophages and MMPs in the early progression of IA, and try to confirm that whether pharmacological therapy that modifies inflammation mediated by macrophages effected in the prevention of progression and growth of IA.

研究证实炎症与颅内动脉瘤（IA）的发生密切相关。但炎症影响IA形成的靶向通路及调控机制尚不明确。我们前期研究发现，瘤壁炎症因子以巨噬细胞最多，而基质金属蛋白酶（MMPs）分泌可能与巨噬细胞有关，那么炎症是否主要通过巨噬细胞促使MMPs分泌才诱导了IA形成还有待证实。既往IA模型建立多采用动脉结扎和局部血管弹性蛋白酶注射，与人体自然IA形成环境差别较大，且所选动物在血管形态、纤溶系统、生活起居方面与人相距甚远，甚至有些动物存在血栓易感和IA自愈倾向，影响了IA模型的真实性和研究结果的正确性。基于这些不足，我们采用弹性蛋白酶定位注射联合血管紧张素II皮下持续泵入，配合动脉粥样硬化饮食构建猴IA模型。采用药物诱导巨噬细胞减少和MMPs缺乏，探索巨噬细胞、MMMPs在影响IA早期形成过程中的靶向通路及调控机制；同时验证巨噬细胞和MMPs抑制剂在预防IA形成中的有效性，为今后IA的防治提供理论依据。

研究证实炎症与颅内动脉瘤（IA）的发生密切相关。但炎症影响IA形成的靶向通路及调控机制尚不明确。我们前期研究发现，瘤壁炎症因子以巨噬细胞最多，而基质金属蛋白酶（MMPs）分泌可能与巨噬细胞有关，那么炎症是否主要通过巨噬细胞促使MMPs分泌才诱导了IA形成还有待证实。既往IA模型建立多采用动脉结扎和局部血管弹性蛋白酶注射，与人体自然IA形成环境差别较大，且所选动物在血管形态、纤溶系统、生活起居方面与人相距甚远，甚至有些动物存在血栓易感和IA自愈倾向，影响了IA模型的真实性和研究结果的正确性。基于这些不足，我们采用弹性蛋白酶定位注射或颞叶开颅弹性蛋白酶缓释联合血管紧张素II皮下持续泵入，配合动脉粥样硬化饮食构建猴IA模型，同时验证巨噬细胞和MMPs抑制剂在预防IA形成中的有效性，为今后IA的防治提供理论依据。我们将动物分为模型组、巨噬细胞敲除组、MMPs敲除组和假手术组，分别进行猴颅内动脉瘤模型制作，采用药物诱导巨噬细胞减少和MMPs缺乏，探索巨噬细胞、MMMPs在影响IA早期形成过程中的靶向通路及调控机制；分别于术后6月、12月行全脑血管造影术，结果提示，术后6月除假手术组外，各组颅内动脉瘤初步形成，但多数呈动脉瘤样扩张，并未形成囊性动脉瘤，继续予高脂饲料喂养及持续高血压诱导。术后12月复查造影提示，各组颅内动脉瘤形成仍不满意，考虑存在动脉瘤自愈可能，影像学上难以发现动脉瘤形成。随后我们于术后18月处死动物，行瘤壁细胞形态学检查，发现动物模型中动脉瘤样扩张较为明显，动脉瘤壁可见众多炎症细胞浸润，尤其以巨噬细胞居多，同时动脉瘤瘤壁可见MMPs高表达，MMPs敲除组次之，巨噬细胞敲除组最少，证实巨噬细胞促使基质金属蛋白酶（MMPs）分泌增多是炎症影响颅内动脉瘤形成的重要机制之一。