IL-18、IL-12及相关因子在大鼠实验性自身免疫心肌炎心肌中的表达时程和特征

Time course and properties of myocardial expression of IL-18, IL-12, and related cytokines in rat experimental autoimmune myocarditis

目的:探讨IL-18、IL-12及相关细胞因子在大鼠实验性自身免疫心肌炎(EAM)心肌中的表达时程和特征。方法:以猪心脏肌球蛋白加等体积弗氏完全佐剂,辅结核杆菌H37Ra株之乳液为抗原,于Lewis大鼠双后肢皮下注射造模(EAM);用胶原酶灌流和网筛过滤法分离纯化心肌细胞;经免疫组化技术评估心肌损伤程度;按实时荧光定量法测急性期和慢性期,IL-18、IL-12及相关因子(IL-18R,IL-18RAcPL,IL-18BP以及IL-12p40,IL-12p35,IL-12Rβ1,IL-12Rβ2)mRNA表达情况。结果:IL-18、IL-12及相关因子表达主要在急性期,免疫后2周表达增多并达峰值(P<0.01,与正常对照组比较),4周后减少,并与EAM病程正相关;IL-18、IL-12及相关因子主要在巨噬细胞表达,其受体复合物在αβT细胞表达;慢性期仅IL-18BP在心肌细胞有表达。结论:IL-18、IL-12及相关因子参与EAM病理过程,各因子主要集中于急性期巨噬细胞和αβT细胞表达。

To explore the time course and properties of myocardial expressions of IL-18, IL-12, and related cytokines in rat experimental autoimmune myocarditis （EAM）, an antigen was prepared with an emulsion of porcine cardiac myosin in isopyknic complete Freund＇s adjuvant, plus Mycobecterium tuberculosis H37Ra strain. EAM model was made by hypodermic injection of the antigen in hind legs of Lewis rats. Then the isolation and purification of cardiocytes were carried out through the methods of collagenase perfusion and mesh screen filtration, respectively. The degree of myocardial damage was evaluated by immunohistochemistry technique. In accordance with real-time fluorescence quantitative RT-PCR, the mRNA expression of IL-18, IL-12 and related cytokines （IL-18R, IL-18RAcPL, IL-18BP and IL-12p40, IL-12p35, IL-12Rβ1, IL-12Rβ2） were examined in the acute-and the chronic-phase. The results showed that the expression of IL-18, IL-12 and related cytokines mainly occurred in the acute phase, the peak value of expression was at 2 week after immunization （P 〈0.01, compared with control）, and diminished at 4 week after immunization, which presented a positive correlation with EAM course. IL-18, IL-12 and related cytokines mainly expressed in macrophage, their receptor complex expressed in αβ T cells, and IL-18BP however, expressed only in cardiac myocytes in the chronic phase. In conclusion, IL-18, IL-12, and related cytokines are involved in the pathological process of EAM. The expression of various related cytokines almost concentrate on macrophage and αβ T cells in the acute phase.