Metoprolol Mitigates Ischemic Heart Remodeling and Fibrosis by Increasing the Expression of AKAP5 in Ischemic Heart

The harm of heart failure mainly causes patients to develop dyspnea, fatigue, fluid retention, and other symptoms, which impair patients' activity tolerance and lead to a dramatic decrease in patients' quality of life. The purpose of this study was to verify whether metoprolol regulates AKAP5 expression and test the role of AKAP5 postinjury in mitigating cardiac infarction-associated tissue remodeling and fibrosis. Sprague-Dawley (SD) rats underwent coronary artery ligation (CAL), which was followed immediately with metoprolol daily. And western blot and coimmunoprecipitation experiments were performed to detect the expression of related proteins in the sham-operated group, model group, and drug-treated group. HW/BW ratio and cardiac expression of COL1 and COL3 were increased in rats following CAL compared with shams. Treatment with metoprolol postinjury was associated with a decrease in HW/BW ratio and COL1/COL3 expression compared to uncontrolled rats. CAL resulted in decreased cardiac AKAP5 expression compared to the control group, while metoprolol treatment restored levels compared to baseline shams. Cardiac expression levels of NFATc3/p-NFATc3 and GATA4 were modest at baseline and increased with injury, whereas metoprolol suppressed gene expression to below injury-associated changes. Immunoprecipitation indicated that AKAP5 could bind and regulate PP2B. In summary, we know that metoprolol alleviates ischemic cardiac remodeling and fibrosis, and the mechanism of alleviating remodeling may improve cardiac AKAP5 expression and AKAP5-PP2B interaction.