病毒性心肌炎小鼠心肌组织中趋化因子表达谱的改变及其意义

Chemokine expression profile and its implications in viral myocarditis

目的 研究病毒性心肌炎 (VMC)小鼠心肌组织趋化因子 (ChKs)表达谱变化 ,探讨ChKs在VMC发病中的可能作用及意义。方法 B3型柯萨奇病毒 (CVB3)腹腔注射雄性BALB c小鼠 ;RT PCR定性和实时定量分析心肌组织MCP 1、IP 10、Ltn和FKN等 12种ChKs表达。病理切片和血清CK MB分析判定病变和病损程度。结果 ( 1)在所检测的 12种ChKs中 ,VMC组呈阳性表达的有 9种 ,显著多于正常组心肌组织的 6种 ,有 3种ChKs(BLC、Eot和LARC)两组均未检出 ;( 2 )VMC组 9种阳性表达的ChKs中CVB3诱导性表达的为MIP 2、MIG和IP 10 ,6种组成性表达的ChKs在VMC时上调表达的有MIP 1β、MCP 1、MCP 2、Ltn等 4种 ,下调表达的有RANTES ,与正常对照相比未呈现明显差异的为FKN。 ( 3)ChKs的表达消长存在一定的差异 ,感染 4d后MIP 2等达高峰 ,随后下降 ;9d后出现MCP 1和RANTES表达上升峰 ;FKN在感染 9d内表达较稳定。 ( 4)亚急性早期、中期、中后期和晚期心肌组织ChKs表达谱有明显区别 ,各期ChKs表达谱中优势表达的ChKs分别为IP 10、IP 10、MCP 1、MCP 1。结论 VMC心肌组织ChKs呈成簇性方式改变 ,表达谱改变的复杂性可能与发病机制的复杂性有关 ,优势表达的ChKs可能在病毒性心肌炎发病中扮演着更重要的角色。

Objective To investigate the profile of chemokine (ChKs) expression in viral myocarditis (VMC) induced by coxsackievirus group B type 3 (CVB3) and to discuss its implications in pathogenesis of VMC. Methods BALB/c mice were inoculated intraperitoneally with CVB3 to establish animal model of VMC. The expression of 12 ChKs including MIP-2, MIG, IP-10, BLC (CXC family), MCP-1, MIP-1β, RANTES, MCP-2, Eotaxin, LARC (CC family), Ltn (C family) and FKN (CX3C family) was qualitatively and quantitatively detected by RT-PCR. Histological changes of VMC were evaluated by hematoxylin and eosin staining, and severity of myocardial injury was determined by detection of serum CK-MB. Results (1) A total of 9 ChKs were detectable in the myocardial tissue of VMC mice, whereas only 6 ChKs were found in normal control. Three ChKs (BLC, Eot and LARC) were not detected in VMC group nor in normal control. (2) 3 out of 9 ChKs (MIP-2, MIG and IP-10) were inducible in VMC group and the others were constitutive. Among the constitutively expressed ChKs, 4 of them including MIP-1β, MCP-1, MCP-2 and Ltn were up-regulated, whereas the RANTES were down-regulated. There was no significant difference between VMC and normal in expression of FKN. (3) Compared with the normal control, the expression patterns of ChKs varied from one to another at different time points in VMC mice. The highest expression level of MIP-2 was found at 4 days after infection and then the expression decreased continuously. The expression of both MCP-1 and RANTES climbed up to a peak after 9 days of infection, while the expression of FKN remained stable within 9 days. (4) The expression profile of the ChKs examined in this study was significantly different among the early, middle and middle-late as well as late stage of VMC, but the dominant ChKs in VMC could be elucidated, i. e. IP-10 dominantly expressed in the early and middle stage of VMC, whereas MCP-1 in the middle-late and late stage. Conclusions The expression of ChKs in myocardial tissue vary significantly in clusters, while complexity of these changes was consistent with that of pathogenesis in VMC. The dominantly expressed ChKs may play a much more important role in pathogenesis of VMC. [