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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., (© 2024. Springer Science+Business Media, LLC, part of Springer Nature.)

We studied the effect of intraperitoneal administration ACTH (4-7) -PGP in doses of 5, 50, 150, and 450 μg/kg to Wistar male rats 12-15 min before modeling restraint stress on the morphofunctional state of the colon. In rats exposed to restraint stress, signs of atrophy and inflammatory reaction in the colon wall, changes in functional activity and number of mast cells, and increased serum level of corticosterone were observed. Administration of the peptide led to a decrease in corticosterone concentration, alleviated stress-induced pathomorphological changes, and promoted adaptation of the intestinal wall to stress. The positive effects of ACTH (4-7) -PGP can be determined by multifunctional nature of the physiological and pharmacological effects of the neuropeptide.

We studied the effect of Semax on the state of intestinal microbiota in rats subjected to restraint stress. Semax was injected to Wistar male rats intraperitoneally in doses of 5, 50, 150, 450 μg/kg 12-15 min before modelling chronic restraint stress. It was found that stress exposure reduced the number of obligate bacteria in the colon microbiota, but increased the content of opportunistic microorganisms. Semax in doses of 50 and 150 μg/kg prevented the stress-induced changes in the composition of colon microbiota. The observed effects of Semax might be mediated by the central neurotropic effects as well as by binding to peripheral melanocortin receptors of the intestine.

We studied the effect of intraperitoneal administration of peptide ACTG 4-7 -PGP to male Wistar rats in doses of 5, 50, 150, and 450 μg/kg on the morphofunctional state of hepatocytes in chronic emotional and painful stress. A dose-dependent stress-limiting effect of the peptide was observed: it normalized the protein synthesis function of the liver and serum activity of ALT. The anticytolytic effect of the peptide increased with increasing its dose against the background of the increase in the relative number of multinucleated and multinucleolated cells and deceleration of the recovery of serum protein concentration. The decrease of hepatocyte cytolysis against the background of more intense morphological signs of protein synthesis processes attests to activation of reparative processes in the liver parenchyma via enhanced constitutional synthesis of protein.

The effect of ACTH4-7-PGP (Semax) intraperitoneal injection at the doses of 5, 50, 150 and 450 μg/kg b. w. on lipid peroxidation and functional hepatocytes state in Wistar male rats subjected to acute and chronic electrical foot-shock stress was investigated. It was observed that peptide at the doses of 50 and 450 μg/kg normalized malondialdehyde (MDA) level elevation in the liver homogenate caused by acute foot-shock stress. On the contrary, at the doses of 5 and 150 μg/kg Semax significantly increased MDA content without essential changes of antioxidant defense activity (catalase, superoxide dismutase, common antioxidative activity). In serum peptide at the all doses decreased stress-induced asparate aminotransferase activity elevation. In chronic stress peptide provided the normalization of protein synthetic hepatocytes function and the serum alanine aminotransferase activity with less effect on lipid peroxidation.