Objective To observe the effects of Toll-like receptor 3 ( TLR3 ) activator-poly ( I∶ C) on vulnerable plaques of atherosclerosis and neovascularization in plaque of mice with ApoE-/ -,and to explore the action mechanism of poly (I∶C)in anti-atherosclerosis. Methods A total of 10 specific pathogen free(SPF)male mice with ApoE-/ -were divided randomly into model group and poly(I∶C) group,with 5 mice in each group. The mice in model group were fed with high fat diet,however, the mice in poly(I∶C)group were fed with high fat diet+poly(I∶C). After 14-week feeding,the mice were sacrificed,and the contents of lipoid vesicles were detected by HE staining. The type andtype Ⅲ collagenous fibers were measured by Movat staining. The macrophages counts ,smooth muscle cells and intraplaque microvessel density were detected by immuneohistochemistry staining, and the plaque vulnerability index was evaluated. The apoptosis area and apoptosis cells in plaques were observed by TUNEL method,and the apoptosis index was calculated. The expression levels of MMP-2,TIMP-1, Bax,Bcl-2 and P53 mRNA and proteins were detected by Real time-PCR and Western blot, respectively. Results As compared with those in model group,the contents of lipoid vesicles,macrophages counts,the apoptosis area,apoptosis index, neovessels and the expression levels of MMP-2,Bax and P53 mRNA and proteins were significantly decreased in poly( I∶C) group,however,the contents of type Ⅰ and type Ⅲ collagenous fibers,smooth muscle cells, the expression levels of TIMP-1, Bcl-2 mRNA and proteins as well as the plaque vulnerability index were significantly decreased in poly( I∶C) group ( P ＜0.05).Conclusion TLR3 activator-poly(I∶C)can effectively reduce intraplaque foam cells,macrophages and microvessel density and increasetype Ⅰ and type Ⅲ collagenous fibers and smooth muscle cells,moreover,which can inhibit cell apoptosis by regulating the expression levels of Bax,Bcl-2 and P53 proteins,so as to increase the stability of the atherosclerosis plaque in ApoE/ mice.%目的 观察TLR3激动剂poly(I∶C)对ApoE-/ -小鼠动脉粥样硬化易损斑块及斑块内新生血管形成的影响,探讨poly(I∶C)抗动脉粥样硬化作用的机制.方法 10只SPF级雄性载脂蛋白E基因敲除( ApoE-/ -)小鼠,随机分为模型组和poly(I∶C)组,每组5只,分别给予高脂饲料、高脂饲料+腹腔注射poly(I∶C)喂养.给药14周后处死小鼠. HE染色检测2组主动脉斑块内脂质空泡含量,Movat染色法观察2组主动脉斑块内Ⅰ和Ⅲ型胶原,免疫组织化学染色法检测2组主动脉斑块内巨噬细胞、平滑肌细胞含量及新生血管密度,评估易损指数;TUNEL染色检测2组主动脉斑块内凋亡阳性面积和细胞凋亡数量,计算凋亡指数;Real time-PCR 和Western blot检测2组MMP-2、TIMP-1、Bax、Bcl-2、P53 mRNA和蛋白表达.结果 与模型组比较,poly(I∶C)组脂质空泡含量、巨噬细胞数量、凋亡阳性面积、细胞凋亡指数、新生血管数及MMP-2、Bax、P53 mRNA和蛋白表达明显减少,Ⅰ和Ⅲ型胶原纤维含量、平滑肌细胞数量、TIMP-1、Bcl-2 mRNA和蛋白表达明显增加,易损指数明显降低,差异均有统计学意义( P ＜0. 05).结论 TLR3激动剂poly(I∶C)能够减少主动脉斑块内脂质空泡、巨噬细胞含量及新生血管数、增加Ⅰ和Ⅲ型胶原纤维、平滑肌细胞数量,并通过调控Bax、Bcl-2、P53基因表达抑制细胞凋亡,从而稳定动脉粥样硬化斑块.
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