Myocardial Protection against Ischemic and Reperfusion Injuries (Experimental Study)

Abstract

The effects of hypoxic, hyperoxic, and hypoxic-hyperoxic preconditioning were examined in the prospective study on narcotized and artificially ventilated rabbits. Under artificial circulation, acute myocardial ischemia was modeled by ligation of anterior descending coronary artery, which was followed by reperfusion. The degree of ventricular arrhythmias was assessed, and the ischemic area was evaluated in percent of the area at risk. Microscopic characterization of the myocardium was employed to assess the cardioprotective effect of hypoxic and/or hyperoxic preconditioning. According to Kruskal-Wallis test, the greatest resistance of the myocardium to ischemic and reperfusion injury was observed after hypoxic-hyperoxic preconditioning (H=42.459; p=0.009). The rabbits subjected to this type of preconditioning demonstrated the least damaged myocardium in comparison with nonconditioned controls.

Influence of Hypoxic and Hyperoxic Preconditioning on Endothelial Function in a Model of Myocardial Ischemia-Reperfusion Injury with Cardiopulmonary Bypass (Experimental Study)

“…Morphometry showed better-preserved myocardial structure with less infarction, and better-preserved myofibrillar structure in preconditioned animals. Our data confirm the prior study demonstrating the cardioprotective effect of HHP [ 15 ]. Data are presented in Figure 7 .…”

“…We investigated myocardial slices and measured ischemic area to risk area ratio in our previous study [ 15 ]. To determine area of risk (hypoperfusion) ligature tightened again, the heart was stained with 5% solution of potassium permanganate, which is administered through the aortic cannula.…”

“…Preconditioning by moderate hypoxia or hyperoxia serves as an effective drug-free method to increase the organism resistance to negative effects including IRI [ 11 , 12 , 13 , 14 , 15 ]. It has been firmly established that the diminished oxygen delivery to the tissues in response to hypoxia is countered by a combination of the increased regional blood flow and the enhanced functional capillary density in the microcirculation [ 16 ].…”

Novel Aspects of Cardiac Ischemia and Reperfusion Injury Mechanisms

“…Своевременная реперфузия миокарда является эффективным терапевтическим вмешательством. Механизм возникновения ИРП имеет хронологическую последовательность [3]. Начинается он с окислительного стресса, затем протекает процесс воспаления, внутриклеточная Ca 2+ -перегрузка, вследствие этого наступает необратимая клеточная смерть, апоптоз и некроз [3,4].…”

“…Механизм возникновения ИРП имеет хронологическую последовательность [3]. Начинается он с окислительного стресса, затем протекает процесс воспаления, внутриклеточная Ca 2+ -перегрузка, вследствие этого наступает необратимая клеточная смерть, апоптоз и некроз [3,4]. ИРП может проявляться по-разному, и только два из них являются обратимыми: аритмия, которая вызвана реперфузией, «оглушение» миокарда, капиллярная обструкция и смертельное миокардиальное реперфузионное повреждение.…”