黄芪甲甙对病毒性心肌炎小鼠心肌中TL1A表达的影响及意义

Effect of astragaloside on TL1A expression in viral myocarditis

目的:观察黄芪甲甙干预的病毒性心肌炎(viral myocarditis,VMC)小鼠中TL1A表达的影响,探讨黄芪甲甙治疗VMC的作用机制。方法:取Balb/c小鼠100只,随机分成6组。非感染小鼠腹腔无菌注射不含病毒的Eagle’s培养液0.1 m L,分为正常对照组10只,以羧甲基纤维素钠0.1 m L灌胃7 d;高剂量对照组10只,9%黄芪甲甙0.1 m L灌胃7 d;余80只小鼠以腹腔无菌注射0.1 m L内含1×102 5 0%组织感染率(TCID50)柯萨奇病毒B3(Cox sachiev ir us B3,CVB3)的Eagle’s培养液制作VMC模型。VMC小鼠随机分为心肌炎对照组和低、中、高剂量干预组,分别以生理盐水和1%,3%,9%黄芪甲甙[分别为0.07,0.2,0.6 g/(kg.d)]0.1 m L灌胃7 d(每组20只)。14 d后处死全部小鼠并取其心脏。采用RT-PCR及免疫组织化学分别检测心肌TL1A m RNA及蛋白表达水平。结果:正常对照组和高剂量对照组无小鼠死亡,心肌炎对照组有大量小鼠死亡,死亡率为45%(9/20),低、中、高剂量干预组小鼠死亡率分别为30%(6/20),25%(5/20),10%(2/20),高剂量干预组小鼠死亡率较心肌炎对照组明显降低(P<0.05),而低、中剂量干预组小鼠死亡率与心肌炎对照组比较,差异无统计学意义(P>0.05);正常对照组和高剂量对照组心肌未见任何病理改变,然而两组心肌中均有一定量的TL1A mRNA及蛋白表达,两组比较差异无统计学意义(P>0.05),心肌炎对照组TL1A mRNA及蛋白表达水平明显增加,与正常对照组比较,差异有统计学意义(P<0.01),心肌炎小鼠经不同剂量黄芪甲甙干预后,与对照组相比,在高剂量干预组显著下降(P<0.01),而低、中剂量黄芪甲甙对心肌炎小鼠TL1A mRNA、蛋白表达水平以及心肌病变积分无明显影响(P>0.05)。结论:黄芪甲甙治疗VMC可能通过抑制炎症介质、降低TL1A的表达而起作用。

Objective: Astragaloside is a simple substance of saponin and the active constituent of astragali. It was reported that the astragaloside exerted therapeutical eff ect on viral myocarditis and dilated cardiomyopathy. The purpose of this study was to investigate the effect of astragaloside on TL1A expression in viral myocarditis. Methods: A total of 100 BALB/c mice were randomly divided into 6 groups: the normal control group(group A, n=10), the high-dose control group(group B, n=10), the myocarditis control group(group C, n=20), the low-dose group(group D, n=20), the middle-dose group(group E, n=20) and the high-dose group(group F, n=20). Mice in group A and group B were injected intraperitoneally with 0.1 m L EMEM solution, while mice in group C, D, E and F were treated with 0.1 m L of 1×102 TCID50 CVB3(diluted in EMEM). Then, mice in group A and group B were treated with carboxymethycellulose solution and 9% astragaloside for 1 week, respectively. At the same time, mice in group C, D, E and F were treated with sodium carboxymethycellulose solution, 1% [0.07 g/(kg.d)], 3% [0.2 g/(kg.d)] and 9%[0.6 g/(kg.d)] astragaloside for 1 week, respectively. After 14 days, the mice were sacrificed and their hearts were collected. The expression levels of TL1A m RNA and protein in the myocardium were examined by RT-PCR and immunohistochemistry, respectively. Results: There was no death in the group A and B. The mortality in the group C, D, E and F was 45%(9/20), 30%(6/20), 25%(5/20) and 10%(2/20), respectively. Compared with the group C, the mortality in the group F was significantly decreased(P<0.05), but there no significant difference in mortality between the group C and the group D or E(P>0.05). There was no any pathological lesion in the group A and B. The TL1A m RNA and protein expression in the myocardium of mice in the group A and B was at low level, with no difference between them(P>0.05). Compared with the group A, the expression levels of TL1A m RNA and protein in the group C were markedly up-regulated(P<0.01), which was dramatically attenuated by the intervention of astragaloside at high dosage(the group F, P<0.01) but not at low(the group D) or middle-dosage(the group E)(P>0.05). Conclusion: Astragaloside may play a pivotal role in protection of the heart injury in viral myocarditis by suppressing the expression of TL1A.