Intracardiac hemodynamics, infarct-limiting effects and myocardial expression of microRNA 223 after necroptosis inhibition in a rat model of heterotopic allogeneic heart transplantation

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Objective.To investigate the effect of necroptosis inhibition on the morphofunctional state of the myocardium and the expression of microRNA 223 after heterotopic allogeneic heart transplantation in rat.Design and methods. Twenty Wistar rats were examined in the study. Animals were divided into the following groups: 1) control (n = 7), 2) dimethyl sulfoxide (DMSO) (n = 6), 3) necrostatin-1s (n = 7). Necrostatin-1s was used as an inhibitor of necroptosis, which was administered intraperitoneally in DMSO solution 1 hour before the start of the experiment at a dose of 1,65 mg/kg. HTK solution cooled to 4 °C was used as a preservation solution. Two hours after heart arrest, the heart was heterotopically transplanted in the abdominal cavity of recipient rat using the scheme “aorta-aorta, pulmonary trunc-posterior vena cava”. Three hours later, intracardiac hemodynamics was assessed by recording the pressure in the left ventricle, heart rate and coronary flow rate in Langendorff-perfused heart. The expression level of microRNA 223–5p and –3p in left ventricular myocardium was assessed using real-time polymerase chain reaction. The plasma levels of troponin I were assessed by enzyme immunoassay. Myocardial infarct size was measured planimetrically at the end of the experiment by staining myocardium with triphenyltetrazolium chloride.Results. Inhibition of necroptosis significantly improved the morphofunctional state of the myocardium, which manifested in a decrease of myocardial infarct size in the necrostatin-1s group compared with the control group and DMSO group. Thus, in the necrostatin-1s group, myocardial infarct size was 25 ± 8,7 %, which was smaller than in the control and DMSO groups (56 ± 9,5 and 57 ± 8,7 %, respectively; p < 0,05). Also in the necrostatin-1s group, lower diastolic intraventricular pressure was recorded, as well as higher values of pulse intraventricular pressure and coronary flow rate than in control group and DMSO group (p < 0,05). Left ventricular myocardium in the necrostatin-1s group demonstrated higher expression of the antinecroptotic miRNA 223–5p and –3p as compared with the control and DMSO groups, as well as lower plasma levels of troponin I (p < 0,05).Conclusions.Pharmacological inhibition of necroptosis in heterotopically transplanted donor heart is accompanied by marked cardioprotective effects and increases the expression of antinecroptotic microRNA 223–5p and –3p.