Laboratory Animal Center, Xi'an Jiaotong University, Xi'an, China.
Department of Vascular Surgery, The Second Hospital of Tianjin Medical University, Tianjin, China.
Animal Model Exp Med. 2024 Jun;7(3):388-395. doi: 10.1002/ame2.12362. Epub 2023 Nov 28.
Intimal hyperplasia (IH) is a negative vascular remodeling after arterial injury. IH occasionally occurs in elastase-induced abdominal aortic aneurysm (AAA) mouse models. This study aims to clarify the incidence and histological characteristics of IH in aneurysmal mice. A retrospective study was conducted by including 42 male elastase-induced mouse AAA models. The IH incidence, aortic diameters with or without IH, and hyperplasia lesional features of mice were analyzed. Among 42 elastase-induced AAA mouse models, 10 mice developed mild IH (24%) and severe IH was found in only 2 mice (5%). The outer diameters of the AAA segments in mice with and without IH did not show significant difference. Both mild and severe IH lesions show strong smooth muscle cell positive staining, but endothelial cells were occasionally observed in severe IH lesions. There was obvious macrophage infiltration in the IH lesions of the AAA mouse models, especially in mice with severe IH. However, only a lower numbers of T cells and B cells were found in the IH lesion. Local cell-secreted matrix metalloproteinases (MMP) 2 was highly expressed in all IH lesions, but MMP9 was only overexpressed in severe lesions. In conclusion, this study is the first to demonstrate the occurrence of aneurysmal IH and its histological characteristics in an elastase-induced mouse AAA model. This will help researchers better understand this model, and optimize it for use in AAA-related research.
内膜增生（IH）是动脉损伤后的一种负性血管重构。IH 偶尔发生在弹性蛋白酶诱导的腹主动脉瘤（AAA）小鼠模型中。本研究旨在阐明在动脉瘤小鼠中 IH 的发生率和组织学特征。通过纳入 42 只雄性弹性蛋白酶诱导的 AAA 小鼠模型进行回顾性研究。分析了 IH 的发生率、有或无 IH 的主动脉直径以及小鼠的增生病变特征。在 42 只弹性蛋白酶诱导的 AAA 小鼠模型中，有 10 只发生轻度 IH（24%），仅有 2 只发生严重 IH（5%）。有和无 IH 的 AAA 节段的外径没有明显差异。轻度和严重 IH 病变均表现出强烈的平滑肌细胞阳性染色，但在严重 IH 病变中偶尔观察到内皮细胞。AAA 小鼠模型的 IH 病变中存在明显的巨噬细胞浸润，尤其是在严重 IH 的小鼠中。然而，在 IH 病变中只发现了较少的 T 细胞和 B 细胞。局部细胞分泌的基质金属蛋白酶（MMP）2 在所有 IH 病变中均高度表达，但 MMP9 仅在严重病变中过表达。总之，本研究首次在弹性蛋白酶诱导的 AAA 小鼠模型中证明了动脉瘤性 IH 的发生及其组织学特征。这将有助于研究人员更好地了解该模型，并优化其用于与 AAA 相关的研究。
