APOPTOSIS
AND EXPRESSION OF BCL-2 AND BAX IN MICE VIRAL MYOCARDITIS
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.