The effect of cardioprotectors on protease-іnhіbіtory potentіal in blood and heart of rats with epinephrine-induced myocardial ischemia

Abstract

Coronary heart disease is one of the major causes of illness and of deaths in Europe, therefore the definition of the signaling pathways involved in cardioprotection represents a challenging goal in order to discover novel pharmacological approaches. One of the mechanisms included in the implementation of signaling methods is proteolysis, so the aim of our study was to study the balance between activity of the proteolytic enzymes and their inhibitors in the experimental myocardial ischemia of rats and the impact of corvitin (C) and doxycycline (D) on these parameters. Ischemia was induced in Wistar rats by the intraperitoneal injection of epinephrine at a dose of 0.2 mg/100 g of weight during 10 days. All animals were divided into 4 groups: 1 – control (8 rats), 2 – rats with epinephrine-induced myocardial ischemia (EIM, n = 10), 3 – rats, which were entered C after completion of epinephrine injections (n = 10), 4 – rats, which accepted D during 6 days after finishing of epinephrine injections (n = 10). The electrical activity of the heart was recorded on an electrocardiogram (ECG). Activities of matrix metalloproteinases 2 and 9 (MMP2, MMP9) were studied by enzyme-zymography, the activity of trypsin-like enzymes (TLE), levels of alpha-1 proteinase inhibitor (IP1) and alpha-2-macroglobulin (α2-МG) in the blood and the heart were determined by spectrophotometric methods. The experimental results suggest that epinephrine injections lead to changes in the ECG typical for ischemic myocardium. The data obtained showed that the protease-іnhіbіtory balance in the blood and in heart was disturbed. Activity of MMP9, proMMP9/2 and level of IP1 increased in blood plasma of rats with EIM, but activities of ММP2, TLE were unchanged in this group. In the heart muscle the activity of MMP2 and level of IP1 increased. Administration of C resulted in the recovery of MMPs level, but disturbed the balance in the system TLE/IP1-α2-МG. Administration of D blocked the activity of MMP9, significantly reduced the activity of MMP2, which testifies the inhibitory effect of this drug on the activity of matrix metalloproteinases. Based on these results, we conclude that definition of protease-inhibitory balance in the blood plasma of patients with coronary artery disease is promising as an additional diagnostic complex and for monitoring of the effectiveness of therapy.