RESUMO
【Objective】 To compare the histological characteristics of porcine pancreatic elastase （PPE） induced abdominal aortic aneurysms （AAA） and angiotensin Ⅱ （AngⅡ） induced AAA in mice. 【Methods】 In the PPE group， the mouse abdominal aorta segment from the infrarenal abdominal aorta to the iliac artery was isolated and its branch arteries were ligated to avoid leakage during PPE perfusion. We perfused the isolated aorta segment with a PPE solution at a concentration of 1.5 U/mL for 5 min and then closed the abdominal cavity. The diameter of the abdominal aorta was measured before and 14 days after the surgery， and the perfusion segment of the arteries was collected at day 14 after the surgery. The histological characteristics of the aneurysm were analyzed and graded by histological and immunohistochemical methods. In the AngⅡ group， ten apolipoprotein E knockout mice were prepared， and AngⅡ [1 000 ng/(kg·min)] was infused with osmotic pumps for 28 days. The aorta was separated and the aneurysm aorta segment was analyzed. The wild type mice were used as normal health controls. 【Results】 In the PPE group， the diameter of the PPE perfused aorta segments increased and was significantly larger than the basal diameter ［（0.52±0.02） mm vs. （1.23±0.11） mm］ at day 14 after surgery. All the ten mice developed AAA after PPE application. The histological results showed typical pathological features of AAA in PPE perfused mice， such as elastic fiber breakage， smooth muscle exhaustion， and increased inflammation. Six of the ten mice developed aneurysms after AngⅡ infusion （6/10）. The aneurysms/dilatations were mostly in the suprarenal abdominal aorta， but also in the thoracic aorta and aortic arch. The histology analysis showed that the formation of arterial dissection was common after AngⅡ infusion， and the typical vascular “false lumen” was found. The breakage of elastic fibers， the exhaustion of smooth muscle damage， and the inflammatory response were not as typical as the PPE model in AngⅡ perfused animals. 【Conclusion】 The histological characteristics of PPE induced AAA are very typical and well present the inflammatory process in the development of aneurysm. The AngⅡ model is suitable for the study of aneurysms combined with aortic dissection. Both models have their own advantages and can complement each other.
RESUMO
Objective:To establish a mouse model of the abdominal aortic aneurysm by elastase perfusion and to provide a reference for the study of the mechanism related to abdominal aortic aneurysm formation.Methods:AAAs were induced by porcine pancreatic elastase (PPE) infusion in male C57BL/6 mice. The control group was perfused with normal saline (Saline). The changes in abdominal aortic diameter were compared at 14 days after perfusion. The diameter of the abdominal aorta stained with HE was measured. The destruction of the elastic plate in the abdominal aortic wall was observed by elastic plate staining. TUNEL assay was used to evaluate the apoptosis in aneurysm tissues.Results:Porcine pancreatic elastase (PPE) perfusion successfully established the mouse model of abdominal aortic aneurysm, in which an aneurysm formation rate was 100% at 14 days after the operation. After modelling, the abdominal aorta diameter in the mouse was significantly increased, higher than that in the control group perfused with normal saline ( P<0.05). In the PPE group, the elastic plate of the aortic wall was straightened and thinned, and interrupted. The proportion of TUNEL-positive cells in the PPE group was significantly higher than that in the control group perfused with normal saline ( P<0.05). Conclusion:Elastase perfusion can stably establish the abdominal aortic aneurysm model, and we observe the destruction of the elastic plate in the medial layer of the abdominal aortic wall and the up-regulation of the apoptosis process in the model. It provides a reference to study the pathogenesis of abdominal aortic aneurysm further.
RESUMO
Objective To investigate the feasibility and effectiveness of inducing rabbit common carotid fusiform aneurysms via the common carotid extravascular digestion method. Methods Sixteen New Zealand white rabbits were randomly assigned into either an experiment group ( n=12 ) or a control group (n=4). Porcine pancreatic elastase 80-400 U were used to incubate and digest 2 to 4 cm segment of artery distal to the origin of right common carotid artery. One week after modeling,intravenous angiography was performed and the length and width of fusiform dilatation of common carotid artery were measured. The fusiform dilated artery was examined with hematoxylin and eosin staining and the vascular morphological changes were observed with scanning electron microscope. Isotonic saline solution was used to incubate common carotid arteries of the 4 New Zealand white rabbits in the control group. After one week,the same method was used to observe the lumen of common carotid artery and intimal changes. Results After the digestion of common carotid artery adventitia,the angiography of 12 New Zealand white rabbits of the experimental group revealed fusiform dilatation of common carotid artery of the 10 model rabbits. The widest diameter of the fusiform artery was 3. 70 ± 0. 32 mm;two rabbits had common carotid artery occlusion. Compared with the control group,the right common carotid artery diameter enlarged significantly in the experimental group (1. 80 ± 0. 16 mm,P<0. 01). The HE staining showed that the lumen widened, adventitia and media reduced. Scanning electron microscope showed intimal inflammatory injury and thrombus attachment. Conclusion Using porcine pancreatic elastase to digest the adventitia of common carotid artery can make fusiform dilatation of common carotid artery in rabbits. Using this method may effectively induce a model of fusiform aneurysm,and it has certain feasibility.