枕大池注射弹性蛋白酶制作大鼠椎基底动脉延长扩张症模型

A model of vertebrobasilar dolichoectasia in rats induced by injection of elastase into cisterna magna

目的探讨枕大池注射弹性蛋白酶建立大鼠椎基底动脉延长扩张症(vertebrobasilar dolichoectasia, VBD)模型的可行性。方法雄性SD大鼠40只,随机分为弹性蛋白酶模型组(20只)和生理盐水对照组(20只)。弹性蛋白酶模型组枕大池内注射0.3 μl浓度为1.5 U/μl的弹性蛋白酶,生理盐水对照组枕大池内注射0.3 μl生理盐水。所有动物均于模型制作后28 d处死。观察两组椎基底动脉延长扩张程度并行常规HE和弹性纤维染色,应用迂曲指数和动脉直径增加百分比判定模型制作是否成功。结果生理盐水对照组和弹性蛋白酶模型组分别有1只和3只大鼠死亡。弹性蛋白酶模型组基底动脉直径较生理盐水对照组显著增粗[(0.452±0.062)mm对(0.284±0.046)mm;t=9.113,P<0.001]。生理盐水对照组无一只呈现VBD形态学特征;弹性蛋白酶模型组15只符合VBD的形态学特征,模型制作成功率为88.2%(15/17)。组织病理学检查显示,弹性蛋白酶模型组血管壁结构破坏,血管壁变薄,内弹力层不连续;生理盐水对照组血管壁结构清晰,壁厚均匀,内弹力层完整连续。结论枕大池注射弹性蛋白酶可成功诱导大鼠VBD,可用于制作大鼠VBD模型。

Objective To investigate the feasibility of a model of vertebrobasilar dolichoectasia (VBD) in rats induced by injection of elastase into cisterna magna. Methods Forty male SD rats were randomly divided into elastase model group (n=20) and saline control group (n=20). The elastase model group was intracisternal injected with 0.3 μl of elastase at a concentration of 1.5 U/μl, and the saline control group was injected with 0.3 μl of normal saline. All the animals were sacrificed at 28 d after model preparation. The degree of VBD was observed in both groups, and conventional HE and elastic fiber stain were performed. The tortuosity index and increased percentage of artery diameter were used to determine whether the model was successful. Results One and three rats died in the saline control group and the elastase model group, respectively. The diameter of the basilar artery in the elastase model group was significantly thicker than that in the saline control group (0.452±0.062 mm vs. 0.284±0.046 mm;t=9.113, P<0.001). None of the saline control groups showed morphological characteristics of VBD, and 15 in the elastase model group met the morphological characteristics of VBD. The success rate of model preparation was 88.2%(15/17). Histopathological examination showed that the structure of the vascular wall of was destroyed, the wall of the blood vessel was thinned, and internal elastic layer was discontinuous in the elastase model group;the saline control group had a clear wall structure, a uniform wall thickness, and a complete continuous elastic layer. Conclusion Injection of elastase into occipital cistern can successfully induce VBD in rats, which can be used to make a rat VBD model.