摘要目的 初步探讨苦参素抗慢性病毒性心肌炎(CVMC)心肌纤维化的作用及其作用机制.方法 以柯萨奇病毒B3株重复增量感染小鼠建立CVMC模型,正常对照组1及正常对照组2同期腹腔注射等体积生理盐水.42 d取模型组8只及正常对照组1小鼠评估CVMC模型制备情况.后将CVMC模型组小鼠随机分为CVMC对照组、卡托普利干预组及苦参素干预组,卡托普利干预组及苦参素干预组按100 mg/(kg·d)灌胃给药28 d;同期给予CVMC对照组及正常对照组2等体积生理盐水灌胃,随后杀死各组小鼠.以苦味酸天狼猩红行心肌胶原组织特异性染色,免疫组织化学方法 及反转录-聚合酶链反应(RT-PCR)法检测心肌组织中血管紧张素Ⅱ(AngⅡ)蛋白及基因水平表达;免疫组织化学法及蛋白免疫印迹(Western blotting)法检测小鼠心肌组织中转化生长因子(TGF-β1)蛋白水平的表达;并运用图像分析软件计算心肌组织中的胶原容积积分(CVF,%)、Ang Ⅱ及TGF-β1阳性面积百分率.结果 42 d CVMC组小鼠心脏左室舒张末期内径(3.95±0.31)mm、左室收缩末期内径(3.13±0.26)mm较正常对照组1[(3.61±0.26)mm、(2.33±0.20)mm]均明显扩大(P均＜0.01);射血分数[(42.1±5.3)%]、短轴缩短率[(20.3±2.4)%]及主动脉血流峰值速度[(61.1±6.7)cm/s]较正常对照组1[(72.9±7.3)%、(36.8±4.1)%、(83.3±9.2)cm/s]均显著降低(P均＜0.01);心率[(375.3±32.2)次/min]较正常对照组1[(343.4±31.3)次/min]明显增快(P＜0.01).42 dCVMC组小鼠心肌组织CVF[(13.95±1.08)%]较正常对照组1[(6.52±1.31)%]显著增加(P＜0.01).70 d CVMC对照组小鼠心肌组织CVF[(14.88±1.11)%]较正常对照组[(26.77±1.32)%]、卡托普利干预组[(9.83±1.15)%]及苦参素干预组[(9.94±1.35)%]均显著增加(P均＜0.01);卡托普利干预组AngⅡ的蛋白[(5.05±1.80)%]及基因(0.248±0.035)表达较CVMC对照组[(26.92±3.21)%、(0.598±0.049)]明显减少(P均＜0.01),但苦参素干预组小鼠心肌组织AngⅡ的蛋白[(23.94±4.58)%]及基因(0.56±0.033)表达较CVMC对照组[(26.92±3.21)%、(0.598±0.049)]无明显差异(P均＞0.05);苦参素干预组小鼠心肌组织TGF-β1的蛋白表达[(7.925±2.082)%、(0.254±0.036)]及卡托普利干预组TGF-β1的表达[(8.138±2.058)%、(0.222±0.038)]均较CVMC对照组[(24.86±3.813)%、(0.544±0.044)]明显降低(P均＜0.01),两组相比差异无统计学意义(P＞0.05).结论苦参素可抑制慢性病毒性心肌炎心肌组织的纤维化,下调心肌组织中TGF-β1的表达可能是其作用机制之一.

abstractsObjective To compare the antifibrotic effect of oxymatrine and captopril in mice with chronic viral myocarditis(CVMC) and determine the possible antifibrotic mechanism of oxymatrine in CVMC.Methods Ninety Balb/c mice were randomly divided into normal control group1(n =10),normal control group 2(ra=10) and CVMC model group(n=70).The mice in CVMC model group were infected with coxsackievirus B_3(CVB_3) on days 0,14 and 28 to establish CVMC model.The volume of CVB3 suspension was 0.20 ml,0.25 ml and 0.30 ml,whose 50% tissue culture infection dose was 109 respectively.The mice in the normal control group 1 and 2 were given normal saline of volumes equal to those of viral suspension given to the model group at the same time points.Echocardiography and collagen specific picrosirius red staining were performed to evaluate the CVMC model on day 42 for the mice of the normal control group 1 and 8 mice of CVMC model group.The remaining mice in CVMC model group were randomly divided into CVMC control group,captopril group and oxymatrine group on day 42.From then on,the mice in captopril group and oxymatrine group were treated with captopril or oxymatrine at the dose of 100 mg/kg,by gavage once a day for 28 days,and meanwhile the mice in CVMC control group and the normal control group were given equal-volume normal saline by gastric garage every day,for 28 days successively.All these mice were sacrificed on day 70.Heart tissue slices were stained with collagen specific picrosirius red and the collagen volume fraction(CVF)was calculated with image analysis software.The expressions of Ang Ⅱand TGF-β1 were determined by immunohistochemistry and Western blotting.Results Compared with normal group 1,the left ventricular end-diastolic internal diameters,left ventricular end-systolic internal diameters and heart rates were significantly increased in CVMC model group(P＜0.05,P＜0.01,P＜0.05,respectively),ejection fractions,fractional shortenings and peak velocity of aorta were all significantly decreased in CVMC model group(P＜0.01 for all comparisons),and CVF levels were significantly increased in CVMC group(P＜0.01)on day 42.Compared with normal control group 2,captopril group and oxymatrine group,CVF levels and the expressions of TGF-β1 were significantly increased in CVMC control group(P＜0.01 for all comparisons)on day 70.The expressions of AngⅡin CVMC control group were higher than those in normal control group and captopril group(P＜0.01 for all comparisons),but there were no significant difference between oxymatrine group and CVMC control group(P＞0.05) on day 70.Conclusion Oxymatrine can inhibit myocardial fibrosis in CVMC,and the mechanisms of its antifibrotic effects might be related with the down-regulation of TGF-β1 expression.