Protective effects of butyrate on perfused mouse hearts subjected to ischemia-reperfusion injury
Authors: Moy Angelina , Gong Yikang , Li Wenxuan , Zhang Aifeng , He Huamei 
Published: May 2023

Introduction: Ischemia-reperfusion injury (IRI) is the consequence of vascular diseases and clinical procedures, which cause severe damage to the involved organs. Although diverse agents have been tested to prevent I/R injury in animal models, no effective agent is available to treat patients yet. Thus, there is an urgent need to develop an effective agent to treat patients with I/R injury. Butyrate, a four-carbon short-chain fatty acid, is a dietary microbial fermentation product normally found in mammalian intestines. This study aimed to examine the effects of butyrate on cardiac function, mitochondrial energy metabolism, redox potential, and oxidative stress in perfused mouse hearts subjected to acute IRI. Methods: C57BL/6 mice were randomly assigned into 3 groups (8 in each group): Control, I/R injury, and I/R injury + butyrate. Following animal euthanasia, the heart was isolated and perfused with Krebs-Henseleit (KH) buffer in the Langendorf mode for a 30-min equilibration. For the Control, the hearts were perfused with KH buffer for additional 160 min. For the I/R injury and I/R injury + butyrate, the hearts were perfused for additional 10 min, then subjected to global, no-flow normothermic ischemia for 30 min followed by reperfusion with KH buffer alone and KH buffer + 4 mM butyrate for additional 120 min, respectively. Cardiac function and energy metabolism were measured continuously and simultaneously with PowerLab system and 31P-NMR spectroscope, respectively. Effluent was collected to determine lactate dehydrogenase (LDH) during the last 5 min. At the end of the reperfusion, the hearts were freeze-clamped to measure (1) cellular energy state and redox couples with high-performance liquid chromatography, (2) hydrogen peroxide (H2O2) level with Amplex Red H2O2 Assay Kit, (3) lipid peroxidation marker malondialdehyde (MDA) with thiobarbituric acid reaction, (4) protein oxidative damage marker protein carbonyl with ELISA. Results: 4 mM butyrate boosted ATP synthesis (as indicated by increases in free intracellular ATP, total ATP content, ATP/ADP ratio and ATP synthesis rate) and improved cardiac functional recovery (as assessed by increases in left ventricular developed pressure, the rate of tension development, and by decreases in end-diastolic pressure and the rate of relaxation) after I/R injury. Concomitantly, butyrate alleviated I/R-induced oxidative stress (as indicated by decreases in LDH release, H2O2, MDA, and protein carbonyl levels. Butyrate affected neither guanosine-, cytidine-, and uridine-based nucleotides, nor their catabolites IMP, adenosine, inosine, hypoxanthine, and xanthine, nor cellular redox couples GSH/GSSG and NADPH/NADP+. However, butyrate increased acetyl-CoA, Acetyl-CoA/Malonyl-CoA and redox couple NADH/NAD+. Conclusions: Butyrate protects the heart against acute myocardial IRI by boosting mitochondrial ATP synthesis and redox potential. Butyrate has therapeutic potential for patients with myocardial IRI. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.