Abstract
INTRODUCTION: Global ischemia reperfusion (I/R) stimulation induced by cardiac arrest (CA) and cardiopulmonary resuscitation (CPR) triggers multiple forms of programmed cell death including pyroptosis and necroptosis, and further results in post-resuscitation myocardial damage. Recently, a specific inhibitor of histone deacetylase 6 activity, tubastatin A (TubA) was preliminarily shown to protect the heart against global and regional I/R stimulation. The present study was designed to investigate the effect of TubA on post-resuscitation myocardial pyroptosis and necroptosis in a porcine model of CA and resuscitation. METHODS: A total of 18 pigs were randomly assigned to one of the following three groups (n = 6 each): Sham group, CA/CPR group, and CA/CPR + TubA group. The setting of 9 min of CA and 6 min of CPR was used to establish the porcine model of CA and resuscitation. A dose of 4.5 mg/kg of TubA was intravenously infused within 1 h after successful resuscitation. Myocardial function including stroke volume and global ejection fraction, and cardiac injury biomarkers including cardiac troponin I and creatine kinase-MB were regularly evaluated for 24 h after resuscitation. Thereafter, the pigs were euthanized, and myocardial tissues were harvested to evaluate the ratio of cell apoptosis, the contents of high mobility group box 1, IL-1β, and IL-18, and the expression levels of caspase 3, gasdermin E (GSDME), GSDME N-terminal (GSDME-N), receptor-interacting protein 1 (RIP1), RIP3, mixed lineage kinase domain-like protein (MLKL), and phosphorylated MLKL (p-MLKL). RESULTS: After resuscitation, stroke volume and global ejection fraction were significantly decreased while serum cardiac troponin I and creatine kinase-MB were significantly increased in the two groups experiencing the CA/CPR procedure compared with the Sham group. However, myocardial dysfunction and cardiac injury were significantly milder in the CA/CPR + TubA group than in the CA/CPR group. At 24 h after resuscitation, apoptosis ratio, pyroptosis-related proteins (caspase 3, GSDME, GSDME-N), necroptosis-related proteins (RIP1, RIP3, MLKL, p-MLKL), and proinflammatory cytokines (high mobility group box 1, IL-1β, IL-18) in myocardium were significantly increased in the CA/CPR and CA/CPR + TubA groups compared with the Sham group. Nevertheless, all of them were significantly decreased in those pigs treated with the TubA compared to the CA/CPR group. CONCLUSIONS: TubA could effectively alleviate post-resuscitation myocardial damage in a porcine model of CA and resuscitation, in which the protective role was possibly related to the inhibition of GSDME-mediated pyroptosis and MLKL-mediated necroptosis.