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目的:探讨小鼠急性病毒性心肌炎(viral myocarditis,VMC)心肌细胞血红素氧合酶-1(heme oxygenase-1,HO-1)基因及其蛋白表达的动态变化。方法:72只清洁级近交系4-6周龄雄性BALB/c小鼠随机分为2组:心肌炎组(V组)40只(腹腔注射CVB3病毒),实验对照组(C组)32只。于病毒接种后第4d、8d、15d、21d分别采血后处死小鼠并留取心脏标本。采用免疫组化法和原位杂交法检测心肌HO-1蛋白及mRNA表达,分光光度计法分间接测定COHb含量,光镜及透射电镜观察心肌组织病理及细胞超微结构改变。结果:(1)心肌炎组可见炎症细胞浸润,心肌细胞可见大面积坏死,晚期可见钙化灶形成;电镜下可见肌原纤维溶解断裂,线粒体膜消失,含溶酶体丰富的单核巨噬细胞浸润,对照组小鼠心肌未见上述变化。(2)血COHb含量变化:心肌炎组小鼠血COHb含量在第8d和第15d均较对照组明显增高,2组差异显著(0.047±0.005和0.031±0.004;0.076±0.006和0.030±0.005,P<0.01)。(3)血清cTnI含量变化:V组小鼠血清cTnI含量与C组比较除第21d无明显差别外,其余各时点均高于C组,差异有统计学意义,P<0.01。(4)HO-1免疫组化结果:心肌炎组HO-1蛋白均成阳性表达,各时点心肌HO-1平均吸光度值均高于对照组(P<0.01)。(5)HO-1mRNA原位杂交结果:心肌炎组HO-1mRNA原位杂交染色各时点均呈阳性表达,各时点吸光度值均高于对照组(P<0.01)。结论:病毒性心肌炎可诱导心肌组织HO-1mRNA及其蛋白的表达,可能是受损心肌发挥自我保护作用机制之一。
Objective: To investigate the dynamic changes of heme oxygenase-1 (HO-1) gene and its protein expression in the myocardium of acute myocarditis (VMC) in mice. Methods: Seventy-two clean-grade inbred male BALB / c mice were randomly divided into 2 groups: 40 in myocarditis group (CVB3), 32 in experimental group (C) . On the 4th, 8th, 15th and 21st days after virus inoculation, the mice were sacrificed and the heart specimens were collected. The expression of HO-1 protein and mRNA were detected by immunohistochemistry and in situ hybridization. COHb content was measured indirectly by spectrophotometer. The pathological changes and ultrastructure of myocardium were observed under light microscope and transmission electron microscope. Results: (1) Inflammatory cell infiltration was found in myocarditis group. Large area of necrosis was found in myocardial cells and calcification was seen in late stage. Electron microscopy showed that myofibrils were lysed and dissolved, mitochondrial membrane disappeared, lysosome-rich monocyte-macrophage infiltration , The control group of mice did not see the above changes in myocardium. (2) Changes of blood COHb content: The levels of COHb in mice with myocarditis were significantly higher than those in the control group on the 8th day and the 15th day (P <0.05), and there was significant difference between the two groups (0.047 ± 0.005 and 0.031 ± 0.004; 0.076 ± 0.006 and 0.030 ± 0.005, P <0.01). (3) Changes of serum cTnI levels: Compared with C group, the serum cTnI level in group V was significantly higher than that in group C except for the 21th day (P <0.01). (4) HO-1 immunohistochemical results: HO-1 protein in myocarditis group were positive expression, the average HO-1 absorbance value at each time point was higher than the control group (P <0.01). (5) HO-1mRNA in situ hybridization results: The expression of HO-1mRNA in myocarditis group was positive at each time point, and the absorbance value at each time point was higher than the control group (P <0.01). Conclusion: Viral myocarditis can induce the expression of HO-1 mRNA and protein in myocardium, which may be one of the mechanisms of self-protection of damaged myocardium.