兔颈动脉粥样硬化狭窄模型的建立及天冬酰胺内肽酶的表达

目的探讨兔颈动脉粥样硬化(AS)狭窄模型中天冬酰胺内肽酶(AEP)的表达。方法将14只新西兰大白兔按随机数字表法分成模型组(8只)和假手术组(6只),模型组通过手术损伤颈动脉内膜。术后两组均给予含镁高脂饲料饲养兔10周,每2周进行体质量称量及血脂检验,术后第5周和第10周末均行MRI观察斑块形成及管腔狭窄情况,术后第10周末收集标本后切片,苏木素-伊红(HE)染色观察病理变化,免疫组化染色分析AEP表达水平。结果模型组1只兔损伤颈动脉死亡。高脂饲养后,两组兔体质量、血脂水平均较术前升高(P0.01)。模型组术后第5周和第10周末两次MRI示管腔狭窄率分别为(16±11)%和(53±20)%,组内差异有统计学意义(t=-4.83,P0.01);假手术组两次MRI均未见管腔狭窄。模型组HE染色可见内膜增生,AS斑块形成,斑块内脂质沉积,巨噬细胞、平滑肌细胞迁移浸润形成泡沫细胞;假手术组未见AS形成。AEP在模型组兔颈动脉组织中高表达,在假手术组中很少表达,吸光度值分别为0.072 0±0.028 0和0.002 0±0.000 9,差异有统计学意义(t=6.61,P0.01)。结论通过损伤颈动脉内膜联合含镁高脂饲料饲养的方法可以确切、可靠、迅速地建立兔颈动脉AS狭窄模型;AEP在颈动脉AS性狭窄病变中呈高表达,可能参与了AS斑块的形成。

Establishment of a model of carotid atherosclerotic stenosis in rabbits and the expression of asparaginyl endopeptidase

Objectives To establish a model of carotid atherosclerotic (AS)stenosis in rabbits and to preliminarily investigate the expression of asparaginyl endopeptidase. Methods Fourteen New Zealand white rabbits were divided into either an model group (n = 8)or a sham operation group (n = 6)according to the random number table. The carotid intima was injured by operation in the model group. The rabbits in both groups were fed with high fat diets containing magnesium for 10 weeks. The rabbits were weighted and their blood lipids were tested every 2 weeks. At the end of the fifth and tenth weeks after procedure,the plaque and vessel stenosis of the rabbits were observed by MRI. At the end of the tenth week after proce-dure,the specimens were collected and sliced. Hematoxylin and eosin (HE)staining was used to observe the pathological changes. Immunohistochemical staining was used to analyze the expression of asparaginyl endopeptidase (AEP). Results One rabbit in the model group died of carotid artery injury. After being fed with high-fat diets,the body quality and the level of blood lipid were increased in the rabbits of both groups compared with those before procedure (all P < 0. 01). At the end of the fifth and tenth weeks after procedure,MRI revealed that the luminal stenosis rates in the operation group were 16 ± 11% and 53 ± 20% respectively. There was significant difference within the group (t = - 4. 83,P < 0. 01). MRI revealed no luminal stenosis twice in the sham operation group. HE staining showed intimal hyperplasia,AS plaque formation,lipid deposition in plaques,macrophage and smooth muscle cells migration and infiltration forming foam cells in the model group. No AS formation was observed in the sham operation group. The expression of AEP was higher in the rabbit carotid artery tissue in the model group,and it expressed rarely in the sham surgery group. The absorbance values were 0. 072 0 ± 0. 028 0 and 0. 002 0 ± 0. 000 9 respectively. There was significant difference (t = 6. 61,P < 0. 01). Conclusions The methods of injuring carotid intima combined with magnesium containing high-fat diet may exactly,reliably,and quickly establish an AS carotid artery stenosis model. AEP may associat with the occurrence of AS plaques.