MINERALOCORTICOID RECEPTOR BLOCKADE AFFECTING THE ADAPTATION STRATEGY OF RATS WITH DIFFERENT STRESS RESISTANCE IN THE POST-TRAUMATIC PERIOD AFTER MYOCARDIAL CONTUSION
The study aims to evaluate the effect of mineralocorticoid receptor blockade on the adaptation strategy of rats with different stress resistance in the post-traumatic period after myocardial contusion. Materials and methods. The stress resistance of rats was evaluated with the Porsolt forced swimming test and open field test. Each category of rats (low-, medium- and high-resistant) was divided into three groups: control, myocardial contusion, heart contusion + eplerenone. The myocardial contusion was simulated using the original device. Prior to injury simulation, rodents received eplerenone injection for 10 days at a dose of 100 mg/kg/day. 24 hours after simulating myocardial contusion and in the control testing, rectal temperature was measured, levels of corticosterone, total protein, albumins, triglycerides, glucose, lactic acid were determined in the blood, the total number of leukocytes, white blood cell count and leukocyte indices were calculated. The total antioxidant capacity and the level of reduced glutathione were determined in the myocardial tissue. Statistical data processing was carried out using methods of descriptive statistics and sample comparison (Mann-Whitney U test). The level of statistical significance is assumed to be 0.05. Data processing was carried out with IBM SPSS Statistics 23. Results. In comparison with the group without pharmacological treatment, low- and medium-resistant rats treated with eplerenone were recorded with significantly lower level of corticosterone, triglycerides, glucose, and lactic acid in blood plasma, as well as higher values of the total antioxidant capacity and the level of reduced glutathione in the myocardium in the post-traumatic period after myocardial contusion. The total number of leukocytes, the percentage of segmented, band neutrophils and the nuclear shift index in rodents treated with eplerenone were statistically significantly lower compared with the other group. The described effects of eplerenone are most likely implemented via the direct cardioprotective effect related to a decrease in the production of free radicals, and mediated by a decrease in heart pre- and afterload.