主动脉夹层患者升主动脉中层弹性蛋白与弹力纤维的变化

目的:探讨Stanford A型主动脉夹层(AD)升主动脉中层弹性蛋白和弹力纤维变化。方法:收集10例Stanford A型AD患者术中获取的升主动脉管壁组织标本与10例脑死亡捐献手术中或冠状动脉旁路移植术中获取的正常升主动脉管壁组织标本,用Westernblot法检测两组标本中膜层弹性蛋白表达;用EVG弹力纤维染色分析两组升主动脉中膜层弹力纤维形态及含量。结果:Westernblot结果显示,AD升主动脉中膜层弹性蛋白含量较正常升主动脉明显降低(0.32±0.07)vs.(1.12±0.17),t=6.722,P=0.003]。EVG染色结果显示,AD升主动脉中膜层弹力纤维形态和排列紊乱,弹力板层断裂、丢失,而正常升主动脉中膜弹力纤维排列紧密、有序,弹力板结构完整,层次分明;AD升主动脉中膜层弹力纤维含量较正常升主动脉明显降低(85762.8±106.2)vs.(164482.8±161.4),t=5.902,P0.001]。弹性蛋白与弹力纤维含量在AD与正常升主动脉中膜层均呈明显正相关(r=0.953、0.973,均P0.001)。结论:StanfordA型AD患者升主动脉中层弹性蛋白和弹力纤维含量下降,弹力纤维形态和结构紊乱,该改变可能在AD的发生中起了重要作用。

Alterations of elastin and elastic fibers in tunica media of ascending aorta in patients with aortic dissection

Objective: To inrestigate the changes of elastin and elastic fibers in the tunica media of the ascending aorta in patients with Stanford type A aortic dissection (AD). Methods: Ten specimens of dissected ascending aortic wall tissue obtained from patients with Stanford type A AD during surgery, and 10 specimens of normal ascending aortic wall tissue taken from brain-dead donors during organ donation surgery or patients undergoing coronary artery bypass grafting were collected. In the tunica media of the two groups of specimens, the elastin expressions were determined by Western blot, and the morphological features and contents of elastic fibers were analyzed by EVG staining. Results: Results of Western blot showed that the elastin level in the tunica media of the dissected ascending aorta was significantly lower than that in the tunica media of the normal ascending aorta (0.32±0.07) vs. (1.12±0.17), t=6.722, P=0.003]. Results of EVG staining demonstrated that the morphology and arrangement of the elastic fibers in the tunica media of dissected ascending aorta were disordered with elastic lamina fracture and loss in dissected ascending aorta, while the elastic fibers were densely and orderly arranged with integrated structure and distinct gradations of the elastic lamina; the content of elastic fibers in tunica media of the dissected ascending aorta was significantly lower than that in tunica media of the normal ascending aorta (85 762.8±106.2) vs. (164 482.8±161.4), t=5.902, P<0.001]. The elastin and elastic fiber contents were positively correlated in tunica media of both dissected and normal ascending aortas (r=0.953, 0.973, both P<0.001). Conclusion: The contents of elastin and elastic fibers are reduced and the morphology and arrangement of the elastic fibers are disordered in the tunica media of ascending aorta in patients with Stanford A type AD, and these changes may play an important role in the pathogenesis of AD.