Changes And Significance Of Serum NT-proBNP Levels In Mice With Viral Myocarditis

Objective:To establish a murine model of viral myocarditis(VMC), the changes of serum N-terminal pro-brain natriuretic peptide(NT-pro BNP) levels in the model mice are detected at different periods. The relationship between NT-pro BNP and cardiac pathology scores is analyzed. Finally, we explore the role of NT-pro BNP in the pathogenesis of VMC.Methods: 100 4-week-old male Balb / c mice were randomly divided into VMC group(60) and control group(40). The VMC group were injected intraperitoneally coxsackievirus B3(CVB3) solution 0.1ml. The control group was injected with the same amount of virus-free DMEM solution. 10 mice of each group were sacrificed on 3, 7, 14,and 28 th day after VMC modeling and their blood and heart tissues were collected.Blood is stood for 30 min and then centrifuged to obtain upper serum. The serum NT-pro BNP levels in two groups of mice were detected by ELISA. Heart is bisected along the long axis, and then fixed in 10% formalin solution. Paraffin section is Prepared. Pathological changes in myocardial tissue were examined with hematoxylin and eosin stain. The cardiac pathology(inflammatory cell infiltration and necrosis)scores are calculated. We use statistic to analyze the changes of serum NT-pro BNP levels and the correlation between serum NT-pro BNP levels and cardiac pathology scores of VMC group, and to further explore the clinical significance of serum NT-pro BNP in the VMC.Results:1. The mice model of VMC was successfully established. VMC mice began abnormal situation such as drinking less, eating less, less activity, hair loss, hair color fades, listlessness, not sensitive to external stimuli, and mortality on the 3th day. The autopsy found epicardial had varying sizes of white dots, patchy necrosis on days 7-14.There was no for this phenomenon in control group. 2. The cardiac pathology score of VMC group inoculated with the virus after 3, 7, 14, 28 days were( 1.20±0.45),(2.60±0.55),(2.00±0.71),(0.80±0.45). The cardiac pathology score of control group were(0.00±0.00). The cardiac pathology score of VMC group compared with control group were significantly higher at different time points and the difference was statistically significant(p<0.01). The serum NT-pro BNP levels of VMC group were significantly higher than that of control group at each time point and the difference was statistically significant(p<0.01). The serum NT-pro BNP levels were positively correlated with myocardial histopathology scores.Conclusion:The serum NT-pro BNP levels of VMC group were significantly increased,and the elevated levels and cardiac pathology scores were correlated positively at different time points. So the NT-pro BNP levels may reflect the severity of myocardial injury and can be judged as one of serum markers for risk stratification in mice with VMC.