Hydrogen-Rich Saline Improves Baroreflex Sensitivity Associated With Oxidative Stress Reduction In Rats With Acute Myocardial Infarction

BackgroundAcute myocardial infarction (AMI) reduces baroreflex sensitivity (BRS).Hydrogen-rich saline (HRS) has been reported to have antioxidant effects and effectivelyprotect against organ damage induced by oxidative stress. The aim of this study was to testthe hypothesis that HRS can improve BRS associated with oxidative stress reductionin rats with AMI.MethodsThe model of AMI was induced by subcutaneous injection of isoproterenol (ISO,200mg/kg/d) for2consecutive days in male Wistar rats, which were randomly divided intofive groups: control, model, high dose HRS (10ml/kg/d), low dose HRS (5ml/kg/d), andVitamin C group. Hemodynamic parameters and BRS were measured in conscious rats.Examination of cardiac function and myocardial histopathology were performed. Also,cardiac marker enzymes in serum were measured. Oxidative stress was evaluated by levelsof malondialdehyde (MDA),8-hydroxyl deoxyguanosine (8-OH-dG) and superoxidedismutase (SOD) and catalase (CAT) activities in heart tissues.ResultsISO-treated rats showed significant increases in levels of creatine kinase-MB andaspartate aminotransferase in serum and significant decrease in maximum and minimumrate of developed left ventricular pressure. These rats also showed declines in BRS, heartrate variability (HRV), systolic blood pressure (SBP), diastolic blood pressure (DBP), andelevation of heart rate, SBP variability (SBPV) and DBP variability (DBPV).In addition,the levels of myocardial MDA and8-OH-dG were enhanced, and myocardial SOD andCAT activities were reduced in isoproterenol-treated rats. Intraperitoneal injection of HRSor vitamin C for a period of3days significantly attenuated isoproterenol-induced cardiac dysfunction, myocardial injury and cardiac oxidative stress; Also, the increases inBRS,HRV, SBP,DBP,and decreases in heart rate, SBPV and DBPV was observed. BRS waspositively correlated with SOD activity and inversely correlated with the levels of MDAand8-OH-dG.. There was no significant correlation between BRS and±dp/dt max andCAT activity.ConclusionsThese results indicate that HRS increases baroreflex function in rats with AMI,probably associated with oxidative stress reduction.