Wnt/β-catenin抑制剂XAV939对心肌梗死大鼠心肌纤维化的影响

Effects of Wnt/β-catenin inhibitor XAV939 on myocardial fibrosis in rats with myocardial infarction

目的探究Wnt/β-catenin信号通路抑制剂XAV939对心肌梗死大鼠心肌纤维化的影响。方法选取60只无特定病原体级3周龄SD大鼠,采用随机数字表法分为假手术组、模型组和抑制剂组,每组20只。除假手术组外各组采用结扎左冠状动脉前降支,制成心肌梗死大鼠模型;抑制剂组从造模后第10天开始腹腔注射Wnt/β-catenin信号通路抑制剂XAV939,连续注射7 d,其余两组注射等量0.9%氯化钠溶液;采用超声心动图检测各组大鼠左心室收缩末期内径(left ventricular end systolic diameter,LVESd)、左心室舒张末期内径(left ventricular end diastolic diameter,LVEDd)、左心室射血分数(left ventricular ejection fraction,LVEF)和左心室短轴缩短率(left ventricular fractional shortening,LVFS);采用图像法检测各组大鼠左心室梗死范围;采用氯胺T法测定羟脯氨酸浓度检测各组大鼠心肌胶原浓度;TUNEL染色分析法分析大鼠心肌细胞凋亡情况;采用蛋白质印记法检测大鼠心肌组织中促心肌纤维化因子转化生长因子-β1(transforming growth factor 1,TGF-β1)和基质金属蛋白酶(matrix metalloproteinase,MMP)-9的表达情况;采用蛋白质印迹法检测大鼠心肌组织Wnt/β-catenin信号通路相关蛋白表达水平。结果TUNNEL染色结果显示,假手术组、模型组、抑制剂组大鼠心肌细胞凋亡率分别为(10.02±2.36)%、(49.36±9.32)%和(22.01±8.32)%;相比假手术组,模型组大鼠LVESd、LVEDd、羟脯氨酸浓度、胶原浓度、心肌梗死面积、TGF-β1蛋白相对表达、MMP-9蛋白相对表达、β-catenin蛋白相对表达均显著升高,LVEF、LVFS显著降低,差异有统计学意义(P<0.05);相比模型组,抑制剂组大鼠LVESd、LVEDd、羟脯氨酸浓度、胶原浓度、心肌梗死面积、TGF-β1蛋白相对表达、MMP-9蛋白相对表达、β-catenin蛋白相对表达均显著降低,LVEF、LVFS显著升高,差异有统计学意义(P<0.05)。结论XAV939通过抑制Wnt/β-catenin信号通路降低大鼠心肌组织中促纤维化因子的表达及胶原的浓度并抑制心肌细胞凋亡,实现防止心肌梗死后心肌纤维化的发生与发展。

Objectives To explore the effects of Wnt/β-catenin signaling pathway inhibitor XAV939 on myocardial fibrosis in myocardial infarction(MI)rats.Methods Sixty specific pathogen free-level 3-week-old SD rats were enrolled and divided into sham operation group,model group and inhibitor group by random number table method,with 20 cases in each group.Except for sham operation group,ligation of left anterior descending coronary artery was applied to prepare MI rat models.On the 10th day after modeling,inhibitor group was intraperitoneally injected with Wnt/β-catenin signaling pathway inhibitor XAV939 for 7 d,while the other two groups were injected with the same volume of 0.9%sodium chloride solution.The left ventricular end systolic diameter(LVESd),left ventricular end diastolic diameter(LVEDd),left ventricular ejection fraction(LVEF)and left ventricular fractional shortening(LVFS)in each group were detected by echocardiogram.The range of left ventricular infarction in each group was detected by image method.The content of hydroxyproline was detected by chloramine T method.The content of myocardial collagen in each group was detected.The myocardial cell apoptosis was detected by TUNEL staining.The expression of pro-myo⁃cardial fibrosis factors transforming growth factor-β1(TGF-β1)and matrix metalloproteinase(MMP)-9 in myocardial tissues was detected by Western blot.The expression levels of Wnt/β-catenin signaling pathway related proteins in myocardial tissues were detected by Western blot.Results TUNNEL staining results showed that the apoptosis rates of myocardial cells in sham operation group,model group and inhibitor group were(10.02±2.36)%,(49.36±9.32)%and(22.01±8.32)%,respectively.Compared with sham operation group,LVESd and LVEDd,contents of hydroxy⁃proline and collagen,myocardial infarction area,relative expression levels of TGF-β1,MMP-9 and β-catenin proteins significantly increased,while LVEF and LVFS significantly decreased(P<0.05).Compared with model group,LVESd and LVEDd,contents of hydroxyproline and collagen,myocardial infarction area,relative expression levels of TGF-β1,MMP-9 and β-catenin proteins significantly decreased,while LVEF and LVFS significantly increased in inhibitor group(P<0.05).Conclusions XAV939 can reduce the expression of pro-myocardial fibrosis factors and content of collagen in myocardial tissues,and inhibit the apoptosis of myocardial cells to prevent the occurrence and development of myocardial fibrosis after MI by inhibiting Wnt/β-catenin signaling pathway.