硫酸吲哚酚对心肌梗死模型小鼠心肌重构的影响

Effect of indoxyl sulfate on myocardial remodeling in a mouse model of myocardial infarction

目的探讨硫酸吲哚酚(IS)对心肌梗死(myocardial infarction,MI)模型小鼠心肌重构的影响。方法C57BL/6J成年雄性小鼠50只,随机分为假手术组(Sham组)10只,硫酸吲哚酚组(Sham+IS组)10只,心肌梗死组(MI组)15只,心肌梗死+硫酸吲哚酚组(MI+IS组)15只。采用左前降支冠状动脉结扎术构建小鼠MI模型,术后第24小时,Sham+IS组和MI+IS组小鼠每天腹腔注射IS 100 mg/kg,Sham组和MI组每天腹腔注射等体积PBS,连续28 d,期间记录各组小鼠存活情况。实验第30天,心脏超声检查评估各组小鼠心脏功能,超高效液相色谱法检测各组小鼠血清中IS浓度,Masson染色评估各组小鼠梗死区心肌纤维化程度,RT-qPCR技术检测心肌组织α-sma、CollagenⅠ基因的表达水平,Western blot技术检测心肌组织TGF-β信号通路标记蛋白TGF-β、p-Smad2、p-Smad3的表达水平。结果实验第30天时,与MI组相比,MI+IS组小鼠存活率显著下降(χ^(2)=5.02,P<0.05)。与Sham组相比,Sham+IS组小鼠血清中IS浓度显著升高(t=54.87,P<0.05),与MI组相比,MI+IS组小鼠血清中IS浓度显著升高(t=38.55,P<0.05)。心脏超声检查示,Sham组和Sham+IS组的小鼠左心室舒张末期内径(LVIDd)、左心室收缩末期内径(LVIDs)、左心室射血分数(LVEF)、左心室短轴缩短率(LVFS)无显著差异(P>0.05);与MI组相比,MI+IS组小鼠LVIDd、LVIDs显著增大(t=3.96、4.31,P<0.05),LVEF、LVFS显著降低(t=5.68、4.07,P<0.05)。Masson染色示,MI+IS组与MI组比较小鼠心肌间质胶原纤维沉积明显增多。RT-qPCR技术检测显示,MI+IS组与MI组相比,小鼠心肌组织α-sma、CollagenⅠ基因的表达水平显著升高(t=8.74、4.78,P<0.05)。Western blot方法检测显示,MI+IS组与MI组相比小鼠心肌组织中TGF-β、p-Smad2、p-Smad3蛋白的表达水平均显著升高(t=4.04~5.64,P<0.05)。结论IS可加重小鼠MI后病理性心肌重构,其机制可能与TGF-β信号通路激活相关。

Objective To investigate the effect of indoxyl sulfate(IS)on myocardial remodeling in a mouse model of myocardial infarction(MI).Methods A total of 50 adult male C57BL/6J mice were randomly divided into sham-operation group(Sham group)with 10 mice,sham operation+indoxyl sulfate group(Sham+IS group)with 10 mice,myocardial infarction group(MI group)with 15 mice,and myocardial infarction+indoxyl sulfate group(MI+IS group)with 15 mice.Left anterior descending coronary artery ligation was performed to establish a mouse model of MI,and at 24 hours after surgery,the mice in the Sham+IS group and the MI+IS group were given intraperitoneal injection of IS(100 mg/kg),while those in the Sham group and the MI group were given intraperitoneal injection of an equal volume of PBS,once a day for 28 consecutive days.The survival status of the mice in each group was recorded during this period of time.On day 30 of the experiment,echocardiography was performed to evaluate the cardiac function of mice in each group.Ultra-performance liquid chromatography was used to measure the serum concentration of IS.Masson staining was used to assess the degree of myocardial fibrosis in the infarct zone.RT-qPCR was used to measure the mRNA expression levels ofα-sma and CollagenⅠin myocardial tissue.Western blot was used to measure the protein expression levels of the TGF-βsignaling pathway marker proteins TGF-β,p-Smad2,and p-Smad3 in myocardial tissue.Results On day 30 of the experiment,the MI+IS group had a significant reduction in the survival rate of mice compared with the MI group(χ^(2)=5.02,P<0.05).Compared with the Sham group,the Sham+IS group had a significant increase in the serum concentration of IS(t=54.87,P<0.05),and compared with the MI group,the MI+IS group had a significant increase in the serum concentration of IS(t=38.55,P<0.05).Echocardiography showed no significant differences between the Sham group and the Sham+IS group in left ventricular internal diameter at end-diastole(LVIDd),left ventricular internal diameter at end-systole(LVIDs),left ventricular ejection fraction(LVEF),and left ventricular fractional shortening(LVFS)(P>0.05).Compared with the MI group,the MI+IS group had significant increases in LVIDd and LVIDs(t=3.96,4.31,P<0.05)and significant reductions in LVEF and LVFS(t=5.68,4.07,P<0.05).Masson staining showed that compared with the MI group,the MI+IS group had a significant increase in interstitial collagen fiber deposition.RT-qPCR showed that compared with the MI group,the MI+IS group had significant increases in the mRNA expression levels ofα-sma and CollagenⅠin myocardial tissue(t=8.74,4.78,P<0.05).Western blot showed that compared with the MI group,the MI+IS group had significant increases in the protein expression levels of TGF-β,p-Smad2,and p-Smad3 in myocardial tissue(t=4.04-5.64,P<0.05).Conclusion IS can aggravate pathological myocardial remodeling in mice with MI,possibly by activating the TGF-βsignaling pathway.