曲尼司特抑制病毒性心肌炎小鼠心肌纤维化的作用

Tranilast inhibits myocardial fibrosis in mice with viral myocarditis

摘要:

目的 探讨曲尼司特对病毒性心肌炎(VMC)小鼠心肌纤维化的作用。方法 72只BALB/C小鼠完全随机分为对照组、模型组和干预组(n=24),对照组小鼠腹腔内注射Eagle's培养液,模型组和干预组腹腔注射科萨奇病毒B3建立VMC模型,干预组建模后予曲尼司特灌胃(每日200mg/kg),维持给药到取材前一天。分别在造模后7、14、28d三个时间点每组各取8只小鼠心肌组织,行苏木精-伊红染色和Masson染色观察病理改变;甲苯胺蓝和硫瑾染色观察肥大细胞(MC)计数;RT-PCR及Westernblot检测结缔组织生长因子(CTGF)、I型胶原蛋白(ColI)的mRNA及蛋白表达量;并分别对CTGFmRNA与MC计数和ColImRNA的表达进行相关性分析。结果 各时间点模型组心肌病理积分及胶原容积分数高于对照组,曲尼司特干预后降低(P<0.05)。模型组MC计数、CTGF和ColImRNA及蛋白的表达高于对照组,曲尼司特干预后降低,但仍高于对照组(P<0.05)。模型组7d、14d时心肌MC计数与CTGFmRNA呈正相关(r=0.439,P=0.049);模型组7d、14d时心肌组织CTGFmRNA与ColImRNA呈正相关(r=0.646,P=0.007),28d时亦呈正相关(r=0.326,P=0.031)。结论 曲尼司特可能通过抑制MC的聚集、降低CTGF和ColI的表达,减轻VMC小鼠心肌纤维化效应。

Abstract:

Objective To investigate the effect of tranilast on myocardial fibrosis in mice with viral myocarditis (VMC). Methods Male balb/c mice (n=72) were randomly divided into control, VMC and tranilast groups (n=24 each). In the VMC and tranilast groups, the mice were infected with Coxsackie virus B3 (CVB3) to prepare VMC model, while the control group was treated with Eagle's medium. After modeling, the tranilast group was administrated with tranilast [200 mg/(kg.d)] until the day before sampling. On days 7, 14 and 28 after CVB3 or Eagle's medium infection, heart specimens (n=8) were taken and examined after Toluidine blue staining and Nissl staining for counts of mast cells (MC), hematoxylin-eosin staining for myocardial pathological changes, and Masson staining for myocardial fibrosis. The expression of CTGF and type I collagen (Col I) in the myocardial tissue was measured by RT-PCR and Western blot. The correlations of CTGF mRNA expression with MC counts and Col I expression were analyzed. Results The myocardial pathological changes and collagen volume fraction in the VMC group were significantly higher than in the control group at all three time points (P<0.05). Tranilast treatment significantly decreased the myocardial pathological changes and collagen volume fraction compared with the VMC group (P<0.05). The mRNA and protein expression of CTGF and Col I increased in the VMC group compared with the control group, and the increases were reduced with tranilast treatment (P<0.05). The number of MC was positively correlated to CTGF mRNA expression on the 7th day and 14th day (r=0.439, P=0.049) in the VMC group. There were positive correlations between the mRNA expression of Col I and CTGF on the 7th day and 14th day (r=0.646, P=0.007) and the 28th day (r=0.326, P=0.031). Conclusions Tranilast may inhibit the aggregation of MC and down-regulate the expression of CTGF, relieving myocardial fibrosis of mice with VMC.