静脉输注间充质干细胞可稳定动脉粥样硬化易损斑块

Intravenous infusion of mesenchymal stem cells can stabilize vulnerable atherosclerotic plaque

目的建立动脉粥样硬化易损斑块(VP)模型,并静脉输注骨髓间充质干细胞(MSCs),验证MSCs对VP稳定性的影响。方法雄性新西兰兔24只,随机分为3组,VP组(n=8)制作VP模型;VP+MSCs组(n=8)制作VP模型后即刻静脉输注1×107 MSCs;SP组(n=8)制作稳定斑块模型。12周末处死所有动物,取右侧颈总动脉行H-E染色和Masson染色,并测量纤维帽厚度和脂核横截面厚度的比值。行免疫组化染色检测斑块内基质金属蛋白酶2(MMP-2)的含量。结果 H-E染色结果:VP组斑块中心可见大量脂核,斑块表面覆盖较薄纤维帽,在斑块肩部可见残存泡沫细胞和大量炎细胞浸润,部分斑块可见破裂及(或)血栓形成;SP组镜下可见粥样硬化斑块形态结构完整,纤维帽较厚,斑块内炎细胞较少,未见斑块破裂;VP+MSCs组形态介于两者之间。帽/核比值SP组>VP+MSCs组>VP组,VP组与VP+MSCs组和SP组比较差异有统计学意义(P<0.01)。Masson染色结果:SP组平滑肌细胞和弹力纤维含量高于其他两组,VP+MSCs组次之,VP组最少。斑块内MMP-2表达水平:VP组斑块内MMP-2大量表达,主要位于纤维帽和脂质核心;与VP组相比,VP+MSCs组和SP组MMP-2的表达减少,差异有统计学意义(P<0.01);VP+MSCs组MMP-2表达高于SP组(P<0.01)。结论 MSCs静脉输注干预兔VP模型,可降低斑块不稳定性,其机制可能与减少炎性细胞聚集、降低MMP-2含量、减少胶原纤维降解有关。

Objective To establish the vulnerable atherosclerotic plaque model with rabbits and treat them with intravenous infusion of bone marrow mesenchymal stem cells （MSCs） , so as to verify the impact of MSCs on the stability of vulnerable plaque （VP）. Methods Totally 24 healthy male New Zealand white rabbits were randomly divided into three groups. Carotid vulnerable atherosclerotic plaque models were made with rabbits in VP group （n= 8） and VP＋ MSCs group （n：8）; VP＋ MSCs group was given intravenous infusion of 1 × 107 MSCs immediately after modeling and VP group was infused with phosphate buffer. Stable atherosclerosis plaque model was made with rabbit in SP group （n= 8）. Animals in all groups were sacrificed at the end of the 12th week, and the right common carotid arteries were collected and subjected to H-E staining and Masson staining, and the cap/core ratio of atherosclerotic plaque was measured. MMP-2 content was examined by immunohistochemistry. Results H-E staining. In VP group the plaque showed a large lipid core and thin fibrous cap, remnants of foam ceils and many inflammatory cells were seen in the plaque shoulder, and some showed rupture plaques and/or thrombosis. In SP group, the structure of plaque was in integrity, with thick fibrous cap and fewer inflammatory cells, and with no plaque rupture. The plaque structure of VPq-MSCs group was between those of the other two groups. The order of cap/core ratio was SP group 〉VP＋MSCs group 〉VP group, with that of VP group being significantly different from those of the other two groups （P〈0.01）. Masson staining. The contents of muscle fiber and elastic fiber were the highest in SP group, followed by VP＋MSCs group, and then by VP group. The level of MMP-2 in VP group was significantly higher than those in the other two groups（P〈0. 01）, and that in VPq-MSCs group was significantly higher than that in SP group （P〈0.01）.Conclusion Intravenous infusion of MSCs can improve the stability of plaques in VP rabbit model, which may be associated with the reduction of inflammatory cells and MMP-2 level, and the subsequent reduction of collagen fiber degradation.