Dexamethasone Alleviates Myocardial Injury in a Rat Model of Acute Myocardial Infarction Supported by Venoarterial Extracorporeal Membrane Oxygenation

Abstract

Myocardial ischemia causes myocardial inflammation. Research indicates that the venoarterial extracorporeal membrane oxygenation (VA ECMO) provides cardiac support; however, the inflammatory response caused by myocardial ischemia remains unresolved. Dexamethasone (Dex), a broad anti-inflammatory agent, exhibits a cardioprotective effect. This study aims to investigate the effect of Dex on a rat model of acute myocardial infarction (AMI) supported by VA ECMO. Male Sprague-Dawley rats (300–350 g) were randomly divided into three groups: Sham group (n = 5), ECMO group (n = 6), and ECMO + Dex group (n = 6). AMI was induced by ligating the left anterior descending (LAD) coronary artery. Sham group only thoracotomy was performed but LAD was not ligated. The ECMO and ECMO + Dex groups were subjected to 1 h of AMI and 2 h of VA ECMO. In the ECMO + Dex group, Dex (0.2 mg/kg) was intravenously injected into the rats after 1 h of AMI. Lastly, myocardial tissue and blood samples were harvested for further evaluation. The ECMO + Dex group significantly reduced infarct size and levels of cTnI, cTnT, and CK-MB. Apoptotic cells and the expression levels of Bax, Caspase3, and Cle-Caspase3 proteins were markedly lower in the ECMO + Dex group than that in the ECMO group. Neutrophil and macrophage infiltration was lower in the ECMO + Dex group than in the ECMO group. A significant reduction was noted in ICAM-1, C5a, MMP-9, IL-1β, IL-6, and TNF-α. In summary, our findings revealed that Dex alleviates myocardial injury in a rat model of AMI supported by VA ECMO.

Blockade of Inflammatory Markers Attenuates Cardiac Remodeling and Fibrosis in Rats with Supravalvular Aortic Stenosis

“…Although this study did not investigate the exact inhibitory mechanisms of DEX and ramipril on the supravalvular aortic stenosis myocardial cytokine generation, our results confirm their significant anti-inflammatory effect, as shown by other studies [27,33,34,43,44,56]. The present study showed that myocardial levels of TNFα, IL1-α and IL-6 were lower after both treatments, DEX and ramipril compared to AS rats.…”

“…Dexamethasone (DEX), as well as other glucocorticoids, is known for its potent antiinflammatory effects, but there are some controversial results regarding its effects on cardiac remodeling and function [27,[29][30][31][32][33][34]. It has been shown that treatment with DEX is able to inhibit inflammatory cytokines, myocardial fibrosis and reactive oxygen species (ROS), resulting in an improvement in cardiac remodeling and cardiac function in an experimental protocol of CHF in rats induced by left coronary artery ligation [27,31,33,34]. In contrast, another study demonstrated that DEX treatment inhibited the regeneration and recovery of cardiac function in the heart of 2-day-old post-myocardium infarction pigs [32].…”