MicroRNA-132 improves myocardial remodeling after myocardial infarction

L. Chen, G.-Y. Wang, J.-H. Dong, X.-J. Cheng

Department of Cardiology, the People’s Hospital of Rizhao, Rizhao, China. chengxiaojing11@163.com

---

• Cardiology

OBJECTIVE: To elucidate the potential role of microRNA-132 in myocardial infarction (MI) and its underlying mechanism.

MATERIALS AND METHODS: The myocardial infarction model was established in WT and microRNA-132 KO mice using the LAD ligation method. WT mice were assigned into the control group (LAD ligation for MI) and sham group. After animal procedures, infarct size was calculated using hematoxylin and eosin (HE) staining and cardiac function was evaluated using echocardiography, respectively. By analyzing differentially expressed microRNAs relative to MI in a microarray, microRNA-132 was screened out and further verified by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR). Hemodynamic parameters and cardiac function indexes in mice were accessed, including scar length/LV length, FS, dp/dtmax, dp/dtmin, ESV, EDV, EF and Tau_w.

RESULTS: QRT-PCR data showed a gradual decrease in microRNA-132 expression in the infarction zone, border zone and remote zone within 7 days after MI. Compared with mice in the control group, microRNA-132 KO mice showed a higher percentage of scar length/LV length at postoperative day 14 and day 28. MicroRNA-132 KO mice showed decreased FS, dp/dtmax and EF, but increased dp/dtmin, ESV and EDV. The injection of different concentrations of microRNA-132 mimics into mice (8 mg/kg, 16 mg/kg and 32 mg/kg) could reduce LVIDD, LVIDs, ESV, EDV, dp/dtmin and Tau_w. However, FS, EF and dp/dtmax increased by the injection of microRNA-132 mimics at postoperative day 28. The injection of 16 mg/kg microRNA-132 mimics significantly reduced the percentage of scar length/LV length in microRNA-132 KO mice than the control group and miR-CO group. After injection of 16 mg/kg microRNA-132 mimics, LVIDD and LVIDs markedly decreased at postoperative day 14 and day 28 compared with the control group and miR-CO group. However, FS was elevated by microRNA-132 mimics.

CONCLUSIONS: MicroRNA-132 is involved in the development of myocardial infarction. The MicroRNA-132 expression is upregulated after myocardial infarction, influencing infarct size and cardiac function.

Free PDF Download