不同时期卡维地洛干预对柯萨奇病毒致心肌纤维化模型小鼠心肌组织炎性因子表达的影响

Effect of Carvedilol on the expression of inflammatory factor in myocardial tissue of the mice with myocardial fibrosis induced by coxsachievirus B3

目的 研究柯萨奇病毒诱导小鼠病毒性心肌炎后心肌纤维化发病中转化生长因子β1（TGF-β1）、结缔组织生长因子（CTGF）、内皮素-1（ET-1）等炎性因子的表达及不同时期应用卡维地洛干预对其影响.方法 雄性BALB/c小鼠40只随机分为对照组、模型组、急性期治疗组、慢性期治疗组,每组10只.对照组皮下注射9 g/L盐水,其余组腹腔注射100TCID50的柯萨奇病毒B3（CVB3） 0.1 mL,以后每2周腹腔接种同批次CVB3,每次递增0.05 mL,共6周;急性期治疗组第2天开始、慢性期治疗组第4周开始给予卡维地洛10mg/（kg·d）灌胃,共2周;对照组和模型组均给予等量9 g/L盐水灌胃.第6周末各组取心脏计算心脏质量指数（HWI）,心肌组织行Masson染色测胶原容积积分（CVF）;酶联免疫吸附试验法检测心肌组织ET-1水平,免疫组织化学检测TGF-β1和CTGF水平;反转录-聚合酶链反应测定三者mRNA表达.结果 与对照组相比,模型组小鼠HWI及心肌组织CVF明显升高,差异有统计学意义（P均＜0.01）;急、慢性期治疗组较模型组下降,差异有统计学意义（P均＜0.01）;且急性期治疗组低于慢性期治疗组,差异有统计学意义（P均＜0.05）;模型组心肌组织中TGF-β1、CTGF、ET-1 mRNA和蛋白的表达明显升高（P均＜0.01）,急、慢性治疗组较模型组下降,且急性期治疗组较慢性期治疗组降低（P均＜0.01）.结论 TGF-β1、CTGF、ET-1参与CVB致心肌纤维化的发病过程,卡维地洛可通过下调炎性因子的过度表达减轻心肌纤维化程度,早期应用效果好.

Objective To study the role of transforming growth factor-β1 （TGF-β1）,connective tissue growth factor （CTGF）and endothelin-1 （ET-1） in myocardial tissues of the mice with myocardial fibrosis induced by coxsachievirus B3 （CVB3） and the effect of Carvedilol intervention for it in acute stage and chronic phase of viral myocarditis.Methods Forty male BALB/c mice were randomly divided into 4 groups （10 cases in each group）：control group,model group,Carvedilol acute phase intervention group,the chronic phase intervention group.Mice in model group and Carvedilol intervention groups were inoculated with CVB3 （100TCID50/0.1 mL） by peritoneal injection fortnightly.Mice in control group were given normal saline（NS） instead equivalently.Mice were poured Carvedilol （10 mg/kg per day for 2 weeks） from the second day in acute phase intervention group and from the fourth week in the chronic phase intervention group,while mice of control group and model group were poured with equivalent NS instead.At the end of 6 weeks,mice were sacrificed.Heart weight index （HWI） was determined.The collagen volume fraction （CVF） of left ventricular myocardial tissue were examined after Masson staining.Expressions of ET-1,TGF-β1 and CTGF were detected by enzyme linked immunosorbent assay and immunohistochemistry staining respectively; the mRNA expression was tested by reverse transcription-polymerase chain reaction.Results Compared with the control group,HWI and CVF of model group increased significantly（all P ＜ 0.01）,those of the intervention groups decreased than those of the model group（all P ＜ 0.01）,and in the acute phase those of the intervention group were significantly lower than those in chronic phase intervention group（all P ＜ 0.05）.The expressions of TGF-β1,CTGF,ET-1 and their mRNA in model group were increased significantly than those in the control group（all P ＜0.01）,and were decreased in acute and the chronic phase intervention group than those in model group（all P ＜0.01）,while those were significantly lower in acute phase intervention group than those in chronic phase intervention group （all P ＜ 0.01）.Conclusions TGF-β1,CTGF and ET-1 may be involved in myocardial fibrosis induced by CVB3.Compared with the chronic phase intervention,the acute phase intervention of Carvedilol can reduce myocardial fibrosis more efficiently by down-regulating the excessive expression of inflammatory factors.