Positive correlation of tumor necrosis factor-alpha early expression in myocardium and ventricular arrhythmias in rats with acute myocardial infarction.
BACKGROUND
Tumor necrosis factor-alpha (TNF-alpha) is found to play important roles in acute myocardial infarction (AMI). Ventricular arrhythmias arising from AMI are leading causes of sudden cardiac death (SCD). We sought to clarify the effect of TNF-alpha early expression on ventricular arrhythmias in rats with AMI and its mechanism.


METHODS
Rats with AMI were induced by left anterior descending coronary branch ligation. The mRNA and protein levels of TNF-alpha in myocardium were detected by real-time fluorescent quantitative PCR, Western blotting and histochemistry. Meanwhile, electrocardiogram was recorded. Different concentrations of TNF-alpha were added to isolated rat hearts in isolated heart perfusions. Effect of TNF-alpha on intracellular Ca(2+) concentration was detected by laser confocal technique.


RESULTS
In AMI rats, mRNA and protein levels of TNF-alpha were higher than control (p <0.05), and the occurrence time of ventricular arrhythmias coincided with the secretion of TNF-alpha. TNF-alpha may cause ventricular arrhythmias in isolated rat heart perfusion models. Intracellular Ca(2+) intensity may quickly be increased by TNF-alpha.


CONCLUSIONS
Our results reveal the positive correlation between TNF-alpha early expression and ventricular arrhythmias in rats with AMI. This effect may be associated with the increased intracellular Ca(2+) intensity caused by TNF-alpha.
Xiao
Hua
H
Laboratory of Cardiovascular Immunology, Institute of Cardiology, Union Hospital, Tong Ji Medical College, Hua Zhong University of Science and Technology, People's Republic of China.
Chen
Zhijian
Z
Liao
Yuhua
Y
Cheng
Xiang
X
Liu
Kun
K
Wang
Yanfu
Y
Wang
Min
M
Guo
Heping
H
D000208:Acute Disease; D000818:Animals; D001145:Arrhythmias, Cardiac / Q000235:genetics / Q000378:metabolism* / Q000503:physiopathology; D002118:Calcium / Q000378:metabolism; D005786:Gene Expression Regulation / Q000235:genetics*; D007150:Immunohistochemistry; D015428:Myocardial Reperfusion Injury / Q000235:genetics / Q000378:metabolism* / Q000503:physiopathology; D009206:Myocardium / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics / Q000378:metabolism*
D014409:Tumor Necrosis Factor-alpha; D002118:Calcium