【摘要】 目的 探讨PCSK9（前蛋白转化酶枯草溶菌素9）抑制剂对小鼠心肌梗死（心梗）后心肌局部血管新生的影响和可能机制。方法 2021年7月于广东药科大学动物实验中心将C57BL/6雄性小鼠随机分为对照组（Control组）、假手术组（Sham组）、安慰剂心肌梗死组（PB Ischemia组）、PCSK9抑制剂心肌梗死组（Pep2-8 Ischemia组），给予结扎冠状动脉血管构建急性心梗模型，假手术组只穿针不结扎。手术组术前7 d每天注射PCSK9抑制剂（Pep2-8）或生理盐水。术后7 d对各组小鼠进行心脏彩超、HE、免疫组化染色，评估PCSK9抑制剂对心梗后小鼠心肌血管新生、炎性反应以及心脏功能的影响。并用Western Blot检测小鼠心肌CD31、PCSK9以及TGF-β蛋白含量。结果 Western Blot检测各组心肌PCSK9表达量，安慰剂心肌梗死组小鼠心肌局部PCSK9表达明显增加（P<0.05）。PCSK9抑制剂（Pep2-8）明显降低心肌梗死后PCSK9的表达（P<0.05）。各组小鼠心脏彩超检查结果表明，PCSK9抑制剂明显改善心肌梗死后小鼠心脏功能，表现为左心室射血分数（LVEF）升高[（21.91±6.8）%比（37.95±2.01）%,P<0.05]，左心室短轴缩短率（LVFS）增加[（12.32±4.98）%比（18.23±3.93）%,P<0.05]；左心室收缩末期直径明显减低[（4.45±0.98）mm比（3.12±0.25）mm,P<0.05]，左心室舒张末期直径明显减低[（4.56±0.54）ms比（3.42±0.13）mm,P<0.05]。HE、免疫组化染色表明，PCSK9抑制剂减少梗死后心肌炎性细胞的浸润（P<0.05），促进心肌局部CD31+血管新生标记物表达的增加（P<0.05）。Western Blot进一步表明，PCSK9抑制剂促进梗死后心肌CD31蛋白的表达（P<0.05）和上调TGF-β信号通路的表达（P<0.05）。结论 PCSK9抑制剂改善心梗后小鼠心脏功能及炎症反应并通过TGF-β信号通路促进梗死后小鼠心肌血管新生。更多还原

【Abstract】 Objective To investigate the effect and mechanism of PCSK9 inhibitor in the angiogenesis after acute myocardial infarction（AMI）. Methods C57BL/6 male mice were randomly divided into the control group（control group）, sham operation group（sham group）, placebo myocardial infarction group（PB ischemia group） and PCSK9 inhibitor myocardial infarction group（PC inhibitor ischemia group）. Mice were subjected to left anteriordescending（LAD） coronary arteryocclusion to establish an AMI model. In the sham operation group,only needles were inserted without ligation. PCSK9 inhibitor（Pep2-8） or normal saline were injected every day before the operation. Seven days after the operation, the mice in each group were examined with cardiac ultrasound and HE staining and immunohistochemistry staining were used to evaluate the effects ofPCSK9inhibitor on myocardial angiogenesis, inflammatory response and cardiac function in the mice after myocardial infarction; Western blot was used to measure the expression of CD31、TGF-β and PCSK9 in the myocardium after AMI. Results The expression of PCSK9 in the myocardium of the PB ischemia group was significantly increasedcompared with the control group and sham group（P<0.05）. Compared with the PB ischemia group, PCSK9 inhibitor（Pep2-8） significantly decreased the expression of PCSK9 after myocardial infarction（P<0.05）. The results of cardiac ultrasound showed that PCSK9 inhibitor significantly improved the cardiac function of the mice after infarction; the left ventricular ejection fraction（LVEF） increased [（21.91±6.8）% vs.（37.95±2.01）%, P<0.05）;left ventricular fractional shortening（LVFS） increased [（12.32 ± 4.98）% vs.（18.23 ± 3.93）%, P<0.05]; the left ventricular end systolic diameter decreased significantly [（4.45 ± 0.98） mm vs.（3.12 ± 0.25） mm, P<0.05] and the left ventricular end diastolic diameter decreased significantly [（4.56±0.54） mm vs.（3.42±0.13） mm, P<0.05]. HE and immunohistochemical staining showed that PCSK9 inhibitor reduced the infiltration of the myocarditis cells after infarction（P<0.05） and promoted the expression of CD31+ in the myocardium（P<0.05）. Western blot further showed that PCSK9 inhibitor promoted the expression of CD31 protein（P<0.05） and up-regulated TGF-β signal pathway（P<0.05）. Conclusion PCSK9 inhibitor could improve cardiac functionand promote myocardial angiogenesis in the mice after infarction by TGF-β signal pathway.更多还原