多西环素对大鼠阿霉素心肌病的防治作用及其机制研究

Matrix metalloproteinase inhibitor doxycycline preventing left ventricular remodeling and failure in a rat model of adriamycin-induced dilated cardiomyopathy

目的研究基质金属蛋白酶(MMPs)抑制剂多西环素(doxycycline,DOX)能否防治阿霉素心肌病(ADRDCM)左室重构及其作用机制。方法♂Wistar大鼠分3组:①阿霉素心肌病组(ADRDCM,n=25),阿霉素2.5mg·kg-1,尾静脉注射,每周1次,连续10wk;②阿霉素心肌病+多西环素治疗组(DOX,n=25),DOX30mg·kg-1,每天1次,灌胃治疗;③正常对照组(CON,n=10)。12wk时进行超声和血流动力学检测评价心功能,硫代巴比妥酸法检测丙二醛(MDA)含量,逆转录聚合酶链反应检测MMP2、MMP9及TIMP1的表达,明胶酶谱法检测MMPs活性。结果DOX组较ADRDCM组死亡率明显降低(16%vs40%,P<0.01)。与CON组相比,ADRDCM组大鼠左室舒张末期内径及收缩末期内径增加,左室短轴缩短率、左室内压最大上升速率和最大下降速率明显降低(P均<0.01)。DOX组左室内径增加程度降低,心功能各项指标改善。ADRDCM组MDA含量较CON组增加(P<0.01),而DOX治疗对MDA含量的增加无影响。ADRDCM组左室心肌MMP2、MMP9mRNA表达较CON组明显升高(P<0.01),MMPs明胶酶活性增加(P<0.01),DOX组明显抑制MMP2、MMP9mRNA表达,明显降低升高的MMPs明胶酶活性,而TIMP1的表达在3组间差异均无显著性(P>0.05)。结论ADRDCM左室心肌MMPs表达及活性上调,MMPs抑制剂多西环素通过抑制MMPs表达及活性可部分逆转ADRDCM左室重构,改善心功能。

Aim To investigate whether matrix metalloproteinase inhibitor doxycycline could prevent left ventricular remodeling and failure in a rat model of adriamycin-induced dilated cardiomyopathy(ADR-DCM). Methods Adult male Wistar rats were randomly divided into 3 groups as follows: ①the ADR-DCM group, in which 2.5 mg·kg -1 of ADR was weekly injected via a tail vein for 10 weeks (n=25); ② concomitant MMP inhibition and ADR(DOX group), in which DOX as a MMP inhibitor was administered by daily gavage at a dose of 30 mg·kg -1·day -1(n=25);③the control group (n=10). Hemodynamics and echocardiographic measurements were obtained at 12 weeks after treatment. Finally, LV samples were collected. The malondialdehyde(MDA) was investigated by the methods of TBA . MMP-2, MMP-9, tissue inhibitors of metalloproteinase-1 (TIMP-1) were measured by RT-PCR, MMP-2 and -9 gelatinolytic activity by gelatin zymography. Results Mortality was significantly lower in DOX-treated rat than in ADR-DCM rat (16% vs 40%, P<0.01). LV cavity dilatation was significantly attenuated in DOX group. Doxycycline could partially normalized FS, dp/dt_ max and dt/dt_ min, indices of LV function, which were significantly reduced in ADR rat(P<0.01). The level of MDA was higher in the ADR-DCM group than in the control group(P<0.01), which was not affected by doxycycline treatment. The gene levels of LV MMP-2, MMP-9 were increased in ADR rat and were attenuated by doxycycline treatment(both P<0.01), but there was nochange in TIMP-1 (P>0.05). LV myocardial MMP-2 and -9 gelatinolytic activities were increased significantly in ADR rat (both P<0.01)and were attenuated by Doxycycline treatment(both P<0.01). Conclusion Increased MMP activity and upregulation of MMP-2, MMP-9 occurred in ADR-DCM; pretreatment with the MMP inhibitor doxycycline can attenuate left ventricular remodeling and failure in a rat model of ADR-DCM by downregulating LV myocardial MMP expression and activity.