| Objective The 4 weeks Balb/c mice were injected intraperitoneally with the CVB3 for preparation of viral myocarditis model. The expression of vitamin D receptor(VDR) in myocardial tissues of mice with viral myocarditis(VMC) at different phases was monitored. In addition, the relationship between expression of VDR and inflammatory pathological changes of VMC mice myocardium was observed in order to explore the role of VDR in VMC mice immune inflammatory mechanisms.Methods Hep-2 cells were recovered, and then were infected with the virus CVB3. Subsequently, the virus was amplified to increase the virulence. When the virus virulence reached certain value, the TCID50 of CVB3 was measured, and after that the virus was collected. 120 4-week-old male BALB/c mice were selected as experimental object. They were divided into two groups randomly: control group(40) and experimental group(80). The mice of experimental group were injected intraperitoneally with Coxsackie virus B3 for the preparation of VMC model. While the mice of control group were dealt with same volume of DMEM cultivate liquid. General growth in mice was observed daily. Moreover, in order to obtain the myocardial specimens, 15 VMC mice and 10 mice of control group were killed respectively at the 3, 7, 14 and 28 th day after intraperitoneal injection. The expression of VDR in mice myocardium was tested dynamically by immunohistochemical technique, and had comparative analysis with the control group mice. In addition, myocardial histopathological changes were examined with the method of hematoxylin and eosin staining. Finally, the correlation between expression of VDR in mice myocardium and the myocardial pathological changes was explored.Results(1) The VMC model was prepared successfully through intraperitoneal injection of CVB3 in male Balb/c mice. The injection of the virus after three days, the activity and diet quantity of experimental mice began to decrease, and appeared hair falling. At the 7th day, the experimental group mice were listlessness, poor hair and thinning. What is more, the mortality reached peak(23.75 %). However, the spirit, diet and activity of control group mice were good, and there were no obvious losing fur and death. Observing heart specimens of mice found that heart outer membrane had visible necrotic lesions of irregular shapes in the experimental group mice.(2) Histopathological observation was implemented after myocardial tissue of mice with HE staining. At the 3th day, few inflammatory cells appeared invasion in mice cardiomyocytes. At the 7th day, large necrotic lesions were appeared, and the inflammation-necrosis reached the peak in myocardial tissue. At the 14, 28 th day, the inflammation-necrosis had visible absorption, especially at the 28 th day. However, the myocardial cells of control group mice grew neatly and without inflammatory infiltration.(3) After intraperitoneal injection, the VDR expression level in myocardium of VMC mice increased significantly and reached the peak at the 7th day, and then declined gradually. What is more, the expression of VDR still kept the high level at the 28 th day. At the 3, 7, 14 and 28 th day, the expression of VDR in VMC mice was 2.39 ±0.23、5.45 ±0.30、4.19±0.26、2.52±0.28, while the expression of VDR in control group mice was 1.64±0.23、1.66±0.19、1.68±0.29、1.64±0.36. The VDR expression in experimental group mice was higher than that of the corresponding of control mice(P < 0.01).(4) The correlation between VDR expression and pathological integral in VMC micemyocardium was analyzed. The results showed that the correlation coefficients were r = 0.927, r = 0.894, r = 0.820 and r = 0.859 at the 3, 7, 14 and 28 th day, respectively. They suggested that there were linear correlation between VDR expression level and pathological integral in VMC mice myocardium(P < 0.01).Conclusion The results suggested that VDR may be involved in the pathogenesis of VMC inflammatory immune process. |
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