C-C趋化因子受体2阳性外泌体抑制单核细胞浸润改善缺血再灌注后心肌损伤的实验研究

Study on C-C motif chemokine receptor-2 positive exosomes inhibited monocytes infiltration in improving myocardial ischemia reperfusion injury

目的探讨C-C趋化因子受体2阳性(CCR2^(+))外泌体调控小鼠心肌缺血再灌注(IR)损伤的作用机制。方法将12只C57小鼠完全随机分为野生型(WT)假手术组、WT手术(IR模型)组、CCR2-外泌体手术组和CCR2^(+)外泌体手术组,其中后3组均构建了心肌IR损伤模型并给予相应处理。超声检测心脏结构及功能;Masson三色特殊染色法检测心脏组织内胶原沉积;转移酶介导的脱氧尿苷三磷酸缺口末端标记法检测心肌细胞凋亡;免疫组织化学染色及实时荧光定量聚合酶链反应法检测单核细胞招募相关C-C趋化因子配体2(CCL2)表达以及单核细胞表面CCR2表达;流式细胞术检测心肌IR后梗死部位淋巴细胞抗原6复合体C(Ly6C)和CD_(43)单核细胞数量。结果心肌IR手术后7 d,CCR2^(+)外泌体手术组小鼠心脏纤维化面积小于IR模型组[(16.8±8.1)%比(45.7±3.8)%];射血分数明显低于WT假手术组,但高于IR模型组;小鼠心肌细胞凋亡数量小于IR模型组;小鼠心脏中CCR2蛋白相对表达量小于IR模型组;小鼠再灌注区域CCR2阳性细胞面积小于IR模型组;小鼠再灌注部位Ly6C+的单核细胞数明显低于IR模型组,CD_(43)^(+)的单核细胞数明显高于IR模型组;小鼠心脏中CCL2 mRNA和蛋白相对表达量小于IR模型组(均P<0.05)。结论CCR2^(+)外泌体表现出明显的抗心肌IR损伤的作用,其机制是CCL2表达减少抑制单核细胞浸润,从而减轻了心肌损伤和抑制心力衰竭。

Objective To investigate the mechanism of C-C motif chemokine receptor-2 positive(CCR2^(+))exosomes in regulating myocardial ischemia reperfusion(IR)injury in mice.Methods Twelve C57 mice were divided into wild-type(WT)sham-operated group,WT operated(IR model)group,CCR2-exosome operated group and CCR2+exosome operated group using a completely randomized method,with the last three groups constructing myocardial IR injury model and provide corresponding treatment.Ultrasound was used to examine the cardiac structure and function.Masson trichrome special staining method was used to detect the collagen deposition in cardiac tissues.Cardiomyocyte apoptosis was detected by transferase-mediated deoxyuridine triphosphate nick-end labeling method.The expressions of C-C motif chemokine ligand-2(CCL2)and CCR2 on the surface of monocytes were detected by immunohistochemical staining and real-time fluorescent quantitative polymerase chain reaction method.Flow cytometry was used to detect lymphocyte antigen 6 complex C(Ly6C)and CD_(43)monocytes in the infarct site after myocardial IR.Results At 7 d after myocardial IR surgery,the area of cardiac fibrosis in CCR2^(+)exosome operated group was smaller than that in IR model group[(16.8±8.1)%vs(45.7±3.8)%];the ejection fraction was significantly lower than that of the WT sham-operated group but higher than that of the IR model group;the number of apoptotic cardiomyocytes in mice was less than that in IR model group.The relative expression of CCR2 protein in the heart of mice was lower than that of the IR model group;the area of CCR2 positive cells in the reperfusion area of the mice was smaller than that of the IR model group;the number of Ly6C+monocytes at the reperfusion site in mice was significantly lower than that in the IR model group;the number of monocytes in CD_(43)^(+)was significantly higher than that in IR model group;the relative expression of CCL2 mRNA and protein in the mouse heart was lower than that in the IR model group(all P<0.05).Conclusions CCR2+exosomes show a significant anti-myocardial IR injury effect.The mechanism is that reduced CCL2 expression inhibits monocyte infiltration,thereby reducing myocardial injury and inhibiting heart failure.