MMP-3、TIMP-1在病毒性心肌炎中的表达及其与心肌胶原的关系

THE EXPRESSION OF MMP-3、TIMP-1 IN MICE WITH VIRAL MYOCARDITIS AND THEIR RELATIONSHIP WITH MYOCARDIAL COLLAGEN

目的:探讨基质金属蛋白酶-3(MMP-3)及金属蛋白酶组织抑制因子-1(TIMP-1)在病毒性心肌炎(VM)小鼠中的作用及其与心肌胶原的关系。方法:62只鼠龄4～6周Balb/c纯种雄性小鼠随机分为,对照组(A组,n=8)、感染组(B组,n=54)2组。B组小鼠腹腔接种0.1ml的CVB3建立VM模型,A组腹腔注射0.1ml不含CVB3的Hep-2细胞冻溶液。B组于注射CVB3后第7、14、28、42天各处死8只小鼠,A组于第42天处死8只小鼠,心脏石蜡切片HE染色计算病理积分,免疫组化方法检测心肌型、型胶原的蛋白表达,逆转录-聚合酶链反应法(RT-PCR)检测心肌MMP-3、TIMP-1mRNA的表达。结果:B组心肌MMP-3表达上调,TIMP-1表达下调,以第14、28天时最显著;TIMP-1于第42天时表达上调;心肌型、型胶原沉积增多,以第28、42天时最显著(P<0.05);MMP-3的表达与病理积分呈正相关。结论:MMP-3/TIMP-1参与VM小鼠的病理过程,可能在心肌胶原重构中起重要作用。

Objective:To explore the role of myocardial matrix metalloproteinases-3 (MMP-3), tissue inhibitor of metalloproteinases-1 (TIMP-1) in mice with viral myocarditis(VM) and their relationships with myocardial collagen.Methods:Sixty-two four to six-week-old male Balb/c mice were divided into two groups randomly. Mice in infected group (n=54) were inoculated intrapritoneally with 0.1 ml of Coxsackievirus B3 (CVB3 Nancy strain). Control mice (n=8) were inoculated intrapritoneally with 0.1 ml of Hep-2′s solution. Eight infected mice were sacrificed on day 7,14,28 and 42 respectively and eight control mice were killed on day 42 after inoculation. Histological cross sections of heart were stained with hematoxylin-eosin and myocardial histopathplogic scores were counted under optical microscope. The expression of myocardial collagen was examined by immunohistochemicalanalysis and analyzed by a computer assisting procedure at every time point of samples of experimental viral myocarditis mice and the controls, and the mRNA expression of MMP-3 and TIMP-1 were detected by reverse transcription-polymerase chain reaction (RT-PCR) at the same time.Result:In virus-infected mice, the mRNA expression of MMP-3 was upregulated and the mRNA expression of TIMP-1 was downregulated significantly on day 14 and day 28 compared with those in controls (P<0.05). The expression of myocardial collagen (Ⅰand Ⅲ) in infected group was increased remarkably compared with controls on day 28 and day 42. The mRNA expression of MMP-3 positively correlated with myocardial histopathological scores.Conclusion:The changes of myocardial MMP-3 and TIMP-1 were associated with myocardial pathologic lesion of VM, and may contributes to myocardial collagen remodeling in myocarditis mice.