CARDIOPROTECTIVE EFFICIENCY OF THE COMBINED APPLICATION OF REMOTE ISCHEMIC PRE- AND POST-CONDITIONING IN RATS IN CASE OF MIOCARDIAL ISCHEMIA/REPERFUSION

The cardioprotective efficacy of the combined use of remote ischemic preconditioning (RIPreC) and remote ischaemic postconditioning (RIPostC) in experimental myocardial ischemia/reperfusion was studied in rats. Experimental myocardial ischemia/reperfusion was reproduced by a 30-minute occlusion of the left coronary artery followed by a period of 120-minute reperfusion. Remote ischemic conditioning was reproduced by short-term occlusion of both femoral arteries followed by reperfusion of the extremities beginning at the following time points: RIPreC– 25 minutes before the end of the myocardial ischemia period, RIPostC - 10 minutes after the end of the myocardial ischemia period, RIPreC + RIPostC– 25 minutes before the start and 10 minutes after the end of myocardial ischemia. It was shown that the combined use of RIPreC and RIPostC had a comparable cardioprotective effect in comparison with each of these methods taken separately. Possible reasons explaining the lack of potentiation of the cardioprotective effect of the combined use of RIPreC with RIPostC can presumably be attributed to: 1) achieving maximum cardioprotection, i.e. the impossibility to further reduce the area of myocardial ischemia, 2) the effect on similar intracellular cardioprotective mechanisms in different conditioning modes.

The Effect of Carbonated Natural Mineral Water on Oxidative Stress in Experimental Myocardial Ischemia

Natural therapeutic factors are widely used as an important adjuvant therapy in various cardiovascular and cerebrovascular disorders. The aim of this study was to assess the role of balneal therapy on oxidative stress parameters in experimental myocardial ischemia induced in rats. 5 groups of 8 rats were used as follow: group 1- control group; group 2 - group swimming in distilled water (DW); group 3- group with myocardial ischemia (MI); group 4 - group with MI swimming in DW; group 5 - group with MI and swimming in carbonated mineral water (CMW). Myocardial ischemia was induced with Isoproterenol. The following oxidative stress/antioxidant blood parameters were assessed for each animal: nitric oxide (NOx), malondialdechyde (MDA), total oxidative stress (TOS), catalase (CAT) and total ant oxidative capacity of plasma (TAC). In group 5 all parameters assessed were significantly improved compared with group 3 and 4. Carbonated mineral water can be used as an adjuvant therapy for improving oxidative stress/antioxidant status in patients with cardiac ischemia, in order to reduce the amplitude of ischemic lesions and to contribute as a prophylactic therapy to a better quality of life for these patients. Continuing this research in humans through clinical studies would be warranted.

Changes of parameters of carbonyl-oxidative stress in rats with experimental myocardial ischemia under the influence of doxycycline

Heart diseases, especially acute myocardial infarction (AMI), belong to the most severe illnesses that often lead to death. Despite a large number of studies, the biochemical mechanisms of AMI and post-infarction myocardial remodeling are poorly understood. Carbonyl-oxidative stress (COS) is one of the more important triggers of the post-infarction complications in these patients, so the neutralizing of the intermediates and final products of COS are a perspective direction in the treatment of AMI. Flavonoide antioxidants as well as inhibitors of carbonylation and glycation of proteins shown the cardioprotective effects but their use have some limitations. Recently, new studies have appeared concerning the cardioprotective action of the doxycycline (DC). This tetracycline antibiotic can inhibit matrix metalloproteinases and proteolysis in extracellular matrix. At the same time, the presence of a multiple-substituted phenol ring can provide the ability of DC to neutralize free radicals, so we hypothesized that it can inhibit the COS. This article compares the effects of small (4,2 mg/kg) and of large (16.8 mg/kg) doses of DC with the effects of classical antioxidants, corvitin and aminoguanidine. The COS-markers and activity of antioxidant enzymes were determined in the blood and subcellular heart fractions of the rats with pituitrin-isoproterenol-induced myocardial damage. It has been established that DC exhibits cardioprotective properties, reducing the formation of products of carbonyl and oxidative modification of biomolecules TBA-active substances, fluorescent end products of glycation (fAGE), aldehyde phenylhydrazones (AFH) and ketone phenylhydrazones (CPH), and a more pronounced effect was shown for the low doses of this drug. Simultaneously, the DC activates enzymes of antioxidant protection, first of all, glutathione peroxidase. Effects of small doses of DC are comparable or exceed the action of aminoguanidine and corvitin, so DC can be useful in the treatment of postinfarction heart failure.