Objective To observe the influence of neuregulin-1 on the cardiac function of post-myocardial infarction rats. Methods Left ventricular MI was created in Sprague-Dawley rats by ligation of the left anterior descending coronary. Six months after the operation, rats were evaluated with echocardiology methods. 36 rats that had an infarct area and a EF around 60% were randomized into 3 groups: MI group(n=12) were injected a blank vehicle fluid intravenously for 5 days, after which they continued to be raised on standard food and water for 30 days. MI+NRG group(n=12), received NRG-1 10μg·kg-1 intravenously for 5 days, after which they continued to be raised on standard food and water for 30 days. MI+Capt group (n=12) received captopril orally (dissolved in their drinking water 2g/L) for 30 days , after which tap water substituted the solution for 5 days. Final echocardiographic and hemodynamic measurements were made at the end of 1 month of therapy. Total RNA was extracted from frozen left ventricular tissues, and was reverse transcribed into first-strand PCR was performed with primers for BNP、ANP. Results Rats treated with neuregulin had a smaller LVDs (P=0.014), a better LVEF (P=0.004 ),and a tendency towards less lung perfusion than untreated rats. Neuregulin decreased the expression of ANP mRNA in the ventricle (P=0.025).Conclusion Neuregulin markedly improved the cardiac function of rats that survived myocardial infarction, and decreased the expression of ANP mRNA in the ventricle. Objective To observe the influence of neuregulin-1 on the cardiac function of post-myocardial infarction rats. Methods Left ventricular MI was created in Sprague-Dawley rats by ligation of the left anterior descending coronary. Six months after the operation, rats were evaluated with 36 rats that had an infarct area and a EF around 60% were randomized into 3 groups: MI group (n = 12) were injected a blank vehicle fluid intravenously for 5 days, after which they continued to be raised on standard food MI + NRG group (n = 12), received NRG-1 10 μg · kg-1 intravenously for 5 days, after which they continued to be raised on standard food and water for 30 days. MI + Capt group (e = 12) received captopril orally (dissolved in their drinking water 2g / L) for 30 days, after which tap water substituted the solution for 5 days. Final echocardiographic and hemodynamic measurements were made at the end of 1 month of therapy. Total RNA was extracted from frozen lef t ventricular tissues, and was reverse transcribed into first-strand PCR was performed with primers for BNP, ANP. Results Rats treated with neuregulin had a smaller LVDs (P = 0.014), a better LVEF (P = 0.004) Neuregulin decreased the expression of ANP mRNA in the ventricle (P = 0.025) .Conclusion Neuregulin markedly improved the cardiac function of rats that survived myocardial infarction, and decreased the expression of ANP mRNA in the ventricle.