Related Experiment Video
Updated: Feb 28, 2026
Herbal Munziq Ameliorates Myocardial Ischemia-Reperfusion Injury by Inhibiting Inflammation
Published on: January 10, 2025
Suppression of miR-34a Expression in the Myocardium Protects Against Ischemia-Reperfusion Injury Through SIRT1
Bi-Cheng Fu1,2, Ji-Lu Lang1,2, Dong-Yang Zhang1,2
11 Department of Cardiovascular Surgery, The Second Affiliated Hospital of Harbin Medical University , Harbin, China .
Abstract:
MicroRNA-34a (miR-34a) is expressed in the myocardium and expression is altered after myocardial injury. We investigated the effects of miR-34a on heart function after ischemia-reperfusion (IR) injury. Cardiomyocytes were isolated from neonatal rat hearts and simulated IR injury was induced in vitro. Following IR injury in rats, infarct size was measured and left ventricular (LV) function was evaluated using echocardiography. Protein expression of silent information regulator 1 (SIRT1), acetylated p53 (ac-p53), Bcl-2 and Bax, and miR-34a and SIRT1 gene levels were analyzed. miR-34a overexpression exacerbated myocardial injury by increasing apoptosis and infarct size and decreasing LV function. Suppression of miR-34a attenuated myocardial IR injury. SIRT1 was negatively regulated by miR-34a and the expression of downstream genes, such as ac-p53, Bcl-2, and Bax were altered correspondingly. Increased expression of miR-34a aggravates injury after IR; miR-34a suppression therapy may represent a new line of treatment for myocardial IR injury.
Insights
MicroRNA-34a (miR-34a) worsens heart function after myocardial ischemia-reperfusion injury. Suppressing miR-34a protects the heart, suggesting miR-34a inhibition as a potential therapy for heart attack recovery.
Area of Science:
- Cardiovascular Biology
- Molecular Medicine
- Genetics and Genomics
Background:
- MicroRNA-34a (miR-34a) is present in the heart and its levels change following myocardial injury.
- Ischemia-reperfusion (IR) injury significantly impacts heart function and cellular integrity.
Purpose of the Study:
- To investigate the role of miR-34a in myocardial IR injury.
- To explore the therapeutic potential of modulating miR-34a in cardiac IR injury.
Main Methods:
- Neonatal rat cardiomyocytes underwent simulated IR injury in vitro.
- Adult rats experienced in vivo IR injury, with infarct size and left ventricular (LV) function assessed via echocardiography.
- Analysis of protein and gene expression for miR-34a, SIRT1, acetylated p53 (ac-p53), Bcl-2, and Bax.
Main Results:
- Overexpression of miR-34a worsened myocardial injury, increasing apoptosis and infarct size while decreasing LV function.
- Suppression of miR-34a demonstrated a protective effect, attenuating IR-induced cardiac damage.
- miR-34a negatively regulated silent information regulator 1 (SIRT1), influencing downstream targets like ac-p53, Bcl-2, and Bax.
Conclusions:
- Elevated miR-34a levels exacerbate myocardial injury following IR.
- Targeting miR-34a through suppression presents a promising therapeutic strategy for managing myocardial IR injury.
