白细胞介素-33对心力衰竭小鼠趋化因子2/趋化因子2受体介导的调节性T细胞表达及心肌纤维化的影响

Effects of interleukin-33 on chemokine 2/chemokine 2 receptor-mediated T regulatory cell expression and myocardial fibrosis in mice with heart failure

目的探究白细胞介素(interleukin,IL)-33对心力衰竭小鼠调节性T(T regulatory,Treg)细胞表达和心肌纤维化的影响以及与趋化因子2(chemokine 2,CCL2)/趋化因子2受体(chemokine 2 receptor,CCR2)通路的关系。方法将48只BALB/c小鼠随机分成假手术组、模型组、IL-33组和IL-33抑制剂组,每组12只,IL-33组尾静脉注射重组IL-33,IL-33抑制剂组注射IL-33抑制剂,除假手术组,其余各组小鼠构建心力衰竭模型,造模24 h后,采用多普勒超声心电图进行检查,记录小鼠心脏收缩末期左心室内径(left ventricular internal dimension at end-systole,LVIDs),舒张末期左心室内径(left ventricular internal dimension at end-diastole,LVIDd)、左心室射血分数(left ventricular ejection fraction,LVEF)和左心室短轴缩短率(left ventricular fraction shootening,LVFS);流式细胞术检测小鼠外周血中Treg细胞百分比;苏木素伊红和Masson染色观察小鼠心脏组织病理学变化,并检测胶原容积分数(collagen volume fraction,CVF);Western blot法检测小鼠心脏组织CCL2、CCR2蛋白水平变化。结果与假手术组相比,模型组小鼠心肌细胞肥大变性,排列不规则,出现坏死及纤维化,LVEF、LVFS和Treg细胞百分比均显著降低(均P<0.05),LVIDs、LVIDd、CVF和CCL2、CCR2蛋白水平均显著升高(均P<0.05)。与模型组相比,IL-33组小鼠心脏组织病变程度减轻,胶原纤维沉积减少,LVIDs、LVIDd、CVF和CCL2、CCR2蛋白水平均显著降低(均P<0.05),LVEF、LVFS和Treg细胞百分比均显著升高(均P<0.05);IL-33抑制剂组小鼠心脏组织病变加重,纤维化及坏死面积增加,LVIDs、LVIDd、CVF和CCL2、CCR2蛋白水平均显著升高(均P<0.05),LVEF、LVFS和Treg细胞百分比均显著降低(均P<0.05)。结论IL-33可减轻心力衰竭小鼠的心肌纤维化程度,可能与抑制CCL2/CCR2通路有关。

Objectives To investigate the effects of interleukin-33(IL-33)on T regulatory(Treg)cell expression and myocardial fibrosis in mice with heart failure and its relationship with chemokine 2(CCL2)/chemokine 2 receptor(CCR2)pathway.Methods Forty-eight BALB/c mice were randomly divided into sham operation group,model group,IL-33 group and IL-33 inhibitor group,with twelve in each group.IL-33 group was injected with recombinant IL-33 via tail vein,while IL-33 inhibitor group was injected with IL-33 inhibitor.Except for the sham operation group,the other groups were used to establish heart failure model.Twenty-four hours after modeling,the Doppler ultrasound electocardiogram was used for examination,and the left ventricular internal dimension at end-systole(LVIDs),left ventricular internal dimension at end-diastole(LVIDd),left ventricular ejection fraction(LVEF)and left ventricular fraction shortening(LVFS)were recorded.The percentage of Treg cells in peripheral blood was detected by flow cytometry.Hematoxylin eosin and Masson staining were used to observe the pathological changes of the heart tissue and to detect the collagen volume fraction(CVF).The protein levels of CCL2 and CCR2 were detected by Western blot.Results Compared with those in sham operation group,cardiomyocytes in model group were hypertro⁃phic and degenerated,arranged irregularly,necrosis and fibrosis appeared,LVEF,LVFS and the percentage of Treg cells were significantly lower(all P<0.05),LVIDs,LVIDd,CVF and CCL2,CCR2 protein levels were significantly higher(all P<0.05).Compared with those in the model group,the degree of cardiac tissue lesion and collagen fiber deposition in IL-33 group were reduced,LVIDs,LVIDd,CVF and CCL2,CCR2 protein levels were significantly lower(all P<0.05),LVEF,LVFS and the percentage of Treg cells were significantly higher(all P<0.05);in the IL-33 inhibitor group,the pathological changes of heart tissue were aggravated,and the area of fibrosis and necrosis increased,LVIDs,LVIDd,CVF and CCL2,CCR2 protein levels were significantly higher(all P<0.05),LVEF,LVFS and the percentage of Treg cells were significantly lower(all P<0.05).Conclusions IL-33 can reduce the degree of myocardial fibrosis in mice with heart failure,which may be related to the inhibition of CCL2/CCR2 pathway.