RESUMO
Oxidative stress is known to act as the trigger of cardiac damage during ischemia-reperfusion (I/R) injury. Postconditioning (PoC) is employed to minimize the consequences of ischemia at the onset of reperfusion. Regarding the well-known antioxidant properties of Nigella sativa (Ns), the aim of this study was to investigate whether Nigella sativa postconditioning (Ns-PoC) could reduce IRI by lowering the formation of reactive oxygen species (ROS). Isolated rat hearts were perfused with the Langendorff apparatus, which were subjected to 20 min of preperfusion, 20 min of global ischemia, followed by 40 min of reperfusion. At the onset of reperfusion, based on the type of intervention group, a 10-min period of Krebs flow was developed along with the treatment, and then the reperfusion with Krebs solution was conducted for 30 min. Heart rate (HR) and left ventricular pressure (LVP) were recorded by isometric transducers connected to a data acquisition system. Thiobarbituric acid reactive substances (TBARS), 4-hydroxynonenal (4-HNE) levels, total thiol groups (-SH) levels, superoxide anion dismutase (SOD), and catalase (CAT) activities in myocardial tissues were detected to evaluate the oxidative stress damage degree. Ns-PoC significantly improved cardiodynamic parameters including left ventricular developed pressure (LVDP), rate pressure product (RPP), and the maximum up/down rate of the left ventricular pressure (± dp/dt) as well as SH groups, SOD, and CAT activities. Moreover, it decreased MDA and 4-HNE levels during early reperfusion. The results of this study showed that Ns-PoC ameliorated cardiac functions in isolated rat heart during I/R injuries by improving myocardial oxidative stress states, which may be related to the antioxidant effect of Ns.