AIM To investigate the role of NOD2 in high-fat diet-induced myocardial ischemia/reperfusion (MI/R) injury in obese mice, and explore its underlying mechanism.
METHODS Cardiac-specific NOD2 knockdown was performed in mice. A model of obesity with MI/R injury was established, and a hypoxia/reoxygenation (H/R) cardiomyocyte (H9c2) model with NOD2 knockdown was also developed. The mRNA and protein expression levels of NOD2 in myocardial tissue were assessed via RT-PCR and Western blotting. Myocardial infarction area was evaluated using TTC staining, and serum levels of cTnI, CK-MB, and LDH were measured using detection kits. Apoptosis-related proteins (Bax, Bcl-2, caspase-3) were analyzed by Western blotting, and H9c2 cell apoptosis was quantified using flow cytometry. Oxidative stress markers (MDA, SOD, ROS) were measured using assay kits and confocal microscopy.
RESULTS Transcriptome analysis of public datasets revealed significant upregulation of NOD2 in heart tissues from both MI/R injury and high-fat diet-induced obesity models. In mice with MI/R injury, the mRNA and protein levels of NOD2 were significantly increased (P<0.01), and this increase was further amplified in the obesity model (P<0.01). Cardiac-specific NOD2 knockdown significantly reduced myocardial infarction area and serum levels of cTnI, CK-MB, and LDH in obese mice (P<0.01). Additionally, the Bcl-2/Bax ratio was significantly upregulated (P<0.01), and caspase-3 expression was reduced (P<0.01). In H9c2 cells, NOD2 knockdown significantly inhibited H/R-induced apoptosis, decreased ROS and MDA levels (P<0.01), and increased SOD activity (P<0.01).
CONCLUSION NOD2 is a key regulator of MI/R injury. Knockdown of NOD2 alleviates MI/R injury in obese mice, and its underlying mechanism may be closely related to the decrease of reactive oxygen species (ROS) levels in cardiomyocytes. This study provides new insights and a foundation for clinical treatment of obesity-related MI/R injury.
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