miR-22-3p在腹主动脉瘤中对金属基质蛋白酶-9作用的实验研究

The Role of miR-22-3p on matrix metalloproteinases in angiotensin II infusion-induced abdominal aortic aneurysm

目的:探讨miR-22-3p在小鼠腹主动脉瘤模型中对金属基质蛋白酶-9(MMP-9)的作用。方法:20只apoE基因敲除(apoE-/-)雄性小鼠均等为血管紧张素II(Ang-II)组与对照组,对照组无处理,Ang-II组给予Ang-II(1 500ng·min^(-1)·kg^(-1),6w)微量泵持续灌注,超声观测6周后腹主动脉成瘤率。6周后取成瘤小鼠血管组织RNA,实时PCR测量miR-22-3p的表达;提取野生小鼠血管组织中平滑肌细胞、成纤维细胞与巨噬细胞进行原代培养,同时进行上述三种细胞系及内皮细胞系的培养,实时PCR检测各种细胞miR-22-3p的表达以发现其细胞来源。取10只apoE-/-雄性小鼠随机分为实验组与对照组,均给予Ang-II微量泵灌注,agomiR-22组内眦静脉注射agomiR-22,对照组内眦静脉注射agomiR空载体(agomiR-NC),每5天1次。6周后超声观测腹主动脉成瘤率,免疫组化染色观察血管组织中MMP-9的表达。结果:与对照组相比,6周后Ang-II组主动脉组织中miR-22-3p表达显著下降[(0.00079±0.00029)vs.(0.00042±0.00023),P<0.05]。在各种原代与细胞系培养中,miR-22-3p仅于平滑肌细胞上表达,在灌泵6周apoE-/-小鼠中补miR-22-3p后,腹主动脉瘤成瘤率明显下降(75%vs.0,P<0.05);MMP-9含量显著下降。结论:在腹主动脉瘤形成过程中,miR-22-3p仅在平滑肌细胞表达且降低,MMP-9升高,但补充后miR-22后降低,提示miR-22-3p可能通过下调MMP-9的表达抑制腹主动脉瘤的发生。

Objective： To study the role of miR-22-3p on MMP-9 in Angiotensin II Infusion-induced Abdominal Aortic Aneurysm. Methods： 20 apo E-/-mice were randomly divided into 2 groups(control groups and angiotensin Ⅱ infusion group） with angiotensin II(1 500 ng·min^-1·kg^-1,6 w）. After 6 weeks of angiotensin infusion,the expression of miR-22-3p was examined by real-time PCR. Bone marrow macrophages、smooth muscle cell and fibroblast were isolated,with their cell lines,to examined the original of miR-22-3p. Injected the agomiR into apo E-/-mice with angiotensin II infusion,to investigate the occurrence of AAA. The expression of MMP-9 was determined by immunohistochemistry. Results： Expression levels of miR-22-3p in angiotensin Ⅱ infusion group were significantly lower than those in sham groups [(0. 00079 ± 0. 00029） vs.(0. 00042± 0. 00023）,P〈0. 05]. miR-22-3p was highest expressed on smooth muscle cell and its cell line. The occurrence of AAA was decreased after injected agomiR-22 with angiotensin II infusion(75% vs. 0,P〈0. 05） and the expression of MMP-9 was significantly decreased(P〈0. 05）. Conclusion： In the formation of AAA,miR-22-3p was only expressed on smooth muscle cells,with MMP-9 decreased. Injected miR-22 into apoE-/-mice with angiotensin Ⅱ infusion may can inhibit the expression of MMP-9 to decrease the occurrence of AAA.