Brain natriuretic peptide expression after acute myocardial infarction in Sprague-Dawlay rats

Objective To investigate left ventricular expression of brain natriuretic peptide(BNP)in Sprague-Dawlay rats with acute myocardial infarction(AMI).Methods Myocardial infarction model was established by anterior descending coronary artery ligation.Rats were randomized to AMI groups(1 day,3 days,7 day,14 days,28 days)and Sham-operated group.Semi-quantitative RT-PCR and Western blot were used to examine BNP mRNA and protein levels in left ventricular.Results Compared with the Sham-operated group,the mRNA and protein levels of BNP in AMI groups were significantly increased at 1 day,BNP mRNA levels were 0.913±0.036 vs 0.757±0.034(P0.05),BNP protein levels were 0.882±0.027 vs 0.565±0.086(P0.05),peaked at 3 days,BNP mRNA and protein levels were 0.971±0.027 and 0.976±0.016 respectively,then decreased,however,it remained higher than that in Sham-operated group even in 28 days,BNP protein levels were.902±0.072 vs 0.757±0.034(P0.05),BNP protein levels were 0.873±0.033 vs 0.565±0.086(P0.05).Conclusion The ventricular expression of BNP is increased after AMI,and presents dynamic changes.