Han B, Ma P-R
Shandong Provincial Hospital, Jinan, China


Objectives: To investigate the role of apoptosis and relative gene Bcl-2 and Bax expression in the development of viral myocarditis (VM).
Methods: One hundred and twenty five Balb/c mice were included in the experiment. Twenty mice in each experimental group inoculated with 109 TCID50 CVB3 0.12 ml and five mice in each control group inoculated with saline were sacrificed on 7, 10, 14, 21, 28 days post-inoculated (p.i.) respectively. Light microscopic, electric microscopic and terminal transferase-mediated dUTP-biotin nick end-labeling (TUNEL) assays quantified inflammation, necrosis, and apoptosis in myocardium. The expression of protein Bcl-2, Bax in myocardium were determined by immunohistochemistry.
Results: 1 .The incidence of VM in the mice which CVB3 were inoculated was 86%. Apoptotic cells included myocytes, endothelial cells and infiltrating cells. TUNEL-positive myocytes increased significantly from 7 to 14 days, then reduced from 21 to 28 days p.i.(p<0.05).The positive rate of mice with TUNEL-positive cell were higher in mice exhibited moderate to severe histopathology than that in mice exhibited mild histopathology (p<0.01). 2. The dynamic changes of Bcl-2 expression level in experimental group showed significant positive correlation with the changes of myocardial histopathologic scores (r=0.93, p<0.01). The amount of Bax protein increased prominently in the myocardium from experimental groups compared with control group (p<0.05). With apoptosis in experimental group increasing significantly from 7 to 14 days p.i., both expression of Bcl -2 and Bax increased remarkably. The infiltrating lymphocytes in the myocardium also expressed Bcl-2 and Bax.
Conclusion :(1) Apoptosis might play an important role in the development of VM. (2) Bcl-2 and Bax gene were involved in the regulation of apoptosis in VM.