Relationship between post-cardiac arrest myocardial oxidative stress and myocardial dysfunction in the rat

Background: reperfusion after resuscitation from cardiac arrest (ca) is an event that increases reactive oxygen species production leading to oxidative stress. more specifically,myocardial oxidative stress may play a role in the severity of post-ca myocardial dysfunction. this study investigated the relationship between myocardial oxidative stress and post-ca myocardial injury and dysfunction in a rat model of ca and cardiopulmonary resuscitation (cpr). ventricular fibrillation was induced in 26 rats and was untreated for 6 min. cpr,including mechanical chest compression,ventilation,and epinephrine,was then initiated and continued for additional 6 min prior to defibrillations. resuscitated animals were sacrificed at two h (n = 9),4 h (n = 6) and 72 h (n = 8) following resuscitation,and plasma collected for assessment of: high sensitivity cardiac troponin t (hs-ctnt),as marker of myocardial injury; isoprostanes (isop),as marker of lipid peroxidation; and 8-hydroxyguanosine (8-ohg),as marker of dna oxidative damage. hearts were also harvested for measurement of tissue isop and 8-ohg. myocardial function was assessed by echocardiography at the corresponding time points. additional 8 rats were not subjected to ca and served as baseline controls.results: compared to baseline,left ventricular ejection fraction (lvef) was reduced at 2 and 4 h following resuscitation (p < 0.01),while it was similar at 72 h. inversely,plasma hs-ctnt increased,compared to baseline,at 2 and 4 h post-ca (p < 0.01),and then recovered at 72 h. similarly,plasma and myocardial tissue isop and 8-ohg levels increased at 2 and 4 h post-resuscitation (p < 0.01 vs. baseline),while returned to baseline 72 h later. myocardial isop were directly related to hs-ctnt levels (r = 0.760,p < 0.01) and inversely related to lvef (r = -0.770,p < 0.01). myocardial 8-ohg were also directly related to hs-ctnt levels (r = 0.409,p < 0.05) and inversely related to lvef (r = -0.548,p < 0.01).conclusions: the present study provides evidence that lipid peroxidation and dna oxidative damage in myocardial tissue are closely related to myocardial injury and lv dysfunction during the initial hours following ca. © 2014 schäfer hackenhaar et al.