病毒性心肌炎小鼠细胞外信号调节激酶表达变化及其意义

Changes of expression of extracellular signal-regulated kinase and its significance in mice with viral myocarditis

目的:探讨病毒性心肌炎小鼠细胞外信号调节激酶(extracellular signal-regulated kinase,ERK)的表达变化及其意义。方法:105只清洁级近交系4～6周龄雄性Balb/C小鼠,随机分为两组,正常对照组40只和心肌炎组65只。心肌炎组小鼠腹腔注射柯萨奇病毒B3复制心肌炎动物模型。在病毒接种后第1、第3、第5、第7和第14天,每组各取8只,留取血清及心脏标本。采用HE染色及电镜观察心肌组织学改变,化学发光免疫法测定血清心肌肌钙蛋白-I(cardiac troponin,cTn-I)含量,Western-blot及免疫组化法检测心肌组织中磷酸化ERK含量,Pearson等级相关分析磷酸化ERK和心肌组织炎症积分、血清cTn-I含量之间的关系。结果:心肌炎组小鼠在病毒接种后第3天出现炎症细胞浸润,炎症积分于第7天达到高峰;心肌损伤标志物血清cTn-I在病毒接种后第3天出现升高,于第5天达到峰值,然后逐渐下降;小鼠在病毒接种后第1、第3、第5天磷酸化ERK含量明显增加,伴核转位,第7天减弱至接近正常对照组水平,第14天磷酸化ERK含量又复增加,表现为早期和晚期2次活化;相关分析结果显示,磷酸化ERK水平和血清cTn-I含量成正相关,和炎症积分之间则无明显相关性。结论:病毒性心肌炎小鼠心肌组织的ERK表现为早、晚期两个活化阶段,这可能和病毒早期所致的心肌损伤及晚期疾病进展有关。

Objective：To explore and discuss the changes of expression of extracellular signal-regulated kinase（ERK）in the viral myocarditis of mice.Methods：A total of 105 inbred male Balb/C mice at 4～6 weeks were divided into two groups：normal control group（n =40）and viral myocarditis group（n =65）.Eight mice of each group were sacrificed on 1,3,5,7 and 14 days,respectively after virus infected.The level of phosphorylated ERK was detected with Western-blot and immunohistochemisty.The serum cTn-I level was detected using chemiluminescene immunoassay method.The histological and ultrastructural changes were observed under light microscope and electron microscope.Results：On the 1st,3rd,5th day after CVB3 inoculated,the level of phosphorylated ERK elevated in viral myocarditis group compared with the normal control group,it dropped on the 7th day just like normal control group,but on the 14th day it elevated again.In the viral myocarditis it showed that virus infection induced biphasic activation of ERK.The scores of inflammation in the group E were began to rise on the 3rd day after virus inoculateda,nd reached the peak on the 7th day.The level of serum cTn-I increased on the the 3rd day after virus inoculateda,nd reached the peak on the 5th day.Correlative analysis showed a positive correlation between phosphorylated ERK and serum cTn-Ib,ut there was no correlationship between phosphorylated ERK and scores of inflammation.Conclusion：Viral myocarditis caused by CVB3 can induce the early and late activation of ERK,and phosphorylated ERK plays an important role in the injury of myocardial cells of viral myocarditis.