Effects of Gly-His-Lys-D-Ala Peptide on Skin Wound Regeneration Processes.

We evaluated the effects of the Gly-His-Lys-D-Ala peptide in a dose 0.5 µg/kg on skin wound regeneration in male Wistar rats (n=80) after initial surgical debridement when administered intracutaneously around the site of injury. Histological (severity of the inflammatory reaction, formation of granulation tissue, and epithelialization terms) and morphometric (number of fibroblastic cells, macrophages, granulocytes, and lymphocytes) studies were performed on autopsy specimens on days 3, 7, 10, and 30 of the experiment. Daily intracutaneous injection of the peptide resulted in an increase in the number of fibroblastic cells and macrophages, as well as in a decrease in the number of granulocytes against the background of active wound contraction on day 30 of the experiment. Thus, Gly-His-Lys-D-Ala alleviated the inflammatory reaction and promoted the regenerative processes.

Parameters of Heart Rate Variability in Male Wistar Rats under Conditions of Different Motor Activity.

We studied heart rate variability indexes in freely moving male Wistar rats at rest and under conditions of increased motor activity (treadmill exercise). Some regularities were revealed in the dynamics of HR, RRNN, Mo, indicator of the adequacy of regulation processes, VLF (msec2, %), HF, LF (%), LF/HF, and IC that characterize changes in the neurohumoral regulation and shifts in the level of cardiac rhythm control at the different stages of the experiment. It was found that changes in motor activity of male Wistar rats were accompanied by the transition of the functional state of the organism to a new level of regulation, which was confirmed by the dynamics of HR, RRNN, Mo, LF, VLF, LF/HF, and IC. These findings can be used as prognostic indicators for assessment of regulatory mechanisms in the body.

Effects of ACTH6-9-Pro-Gly-Pro Peptide on the Levels of Pro- and Anti-Inflammatory Cytokines in Wistar Rats under Conditions of Chronic Restraint Stress.

We evaluated the effect of ACTH6-9-Pro-Gly-Pro (ACTH6-9-PGP) peptide on the serum levels of pro- and anti-inflammatory cytokines in experimental animals under conditions of chronic restraint stress. Stress exposure over 2 weeks led to an increase in the levels of IL-1ß, IL-6, and IFNγ in rats. Daily intraperitoneal injection of ACTH6-9-PGP in a dose of 5 µg/kg before stress exposure significantly decreased the levels of IL-6 and IFNγ by 4.8 and 49.3% respectively. Administration of the peptide in a dose of 50 µg/kg decreased the levels of IL-1ß and IFNγ by 51.2 and 39.7%, respectively. However, no changes in the cytokine levels were observed after injection of the peptide in a dose of 500 µg/kg. Thus, ACTH6-9-PGP administered in doses of 5 and 50 µg/kg prevented the stress-induced changes in the levels of pro- and inflammatory cytokines.