Effect of gliprolines on lipid peroxidation rate in male rats’ immunocompetent organs under conditions of information stress

Introduction. The study of various aspects of the stress-reactivity of the body’s immune system, along with the search for correction tools characterized by immunoregulatory properties, is one of the most relevant areas of physiology and pharmacology. Currently, neuropeptides belonging to the group of glурrоlins (the registered drug “sеlаnk” and the new compounds Рro-Glу-Рro-Leu and Рro-Glу-Рro) are of particular interest in practical application as promising bioregulators, in particular their effects on the processes of free radical oxidation, as well as the ability to restore changes from the immune system, including those formed in response to stress.The aim of the study: was to study the effect of glурrоlins on the intensity of lipid peroxidation, catalase activity in the spleen and thymus of male rats under experimental information stress.Material and methods. The study was performed on white nonlinear male rats on which the model of information stress, based on the formation of behavior in animals in a multi-alternative food-producing maze, was reproduced for 20 days. The initial content of malondialdehyde, the rate of spontaneous and ascorbate-dependent lipid peroxidation were determined by standard spectrophotometric methods, and the activity of catalase in the homogenate of the thymus and spleen of experimental animals was evaluated.Results. Under the studied stress conditions, an increase in peroxidation processes was noted. Against the background of the introduction of sеlаnk, Рro-Glу-Рro and Рro-Glу-Рro-Leu, the suppression of the intensity of lipid peroxidation processes in the homogenates of the spleen and thymus tissue of male rats was established (a decrease in the initial level, the rate of spontaneous and ascorbate-dependent lipid peroxidation).Conclusions. Injection of neuropeptides belonging to the group of glyprolins (sеlаnk, Рro-Glу-Рro-Leu and Рro-Glу-Рro) under informational stress conditions contributes to the suppression of the intensity of lipid peroxidation processes, which indicates the stress-protective and immunocorrective effect of the studied substances

Effects of glyprolines on free-radical oxidation in the brain neocortex of white rats in mild traumatic brain injury

The aim of the study was to compare the effect of glyproline peptides RGRGP (Arg-Gly-Arg-Gly-Pro), RGP (Arg-GlyPro), PRPGP (Pro-Arg-Pro-Gly-Pro) and PGPL (Pro-Gly-Pro-Leu) peptide substances at various concentrations on the free radical oxidation intensity of the brain tissues of Wistar males after intraperitoneal administration of peptide solutions after traumatic brain injury.Material and methods. The brain tissue of Wistar males aged 2–3 months (n = 126) were used in the experiment. RGRGP, RGP, PRPGP, and PGPL peptides were provided by Academician N.F. Myasoyedov. Traumatic brain injury (TBI) was modeled by free fall of a load. From the second to the fifth day of the experiment, the animals were injected intraperitoneally with peptides. On the sixth day, the animals were taken out of the experiment. The activity of free radical oxidation was determined in freshly prepared homogenates of sections of the cerebral cortex by chemiluminescence (CL).Results. TBI significantly enhance free-radical oxidation intensity of the neocortex in brain tissue of Wistar rats, and the studied peptides affect it in different ways - from a decrease in CL intensity (the minimum value in TBI + RGP 0.1 group) to its increase (the maximum value in TBI + RGPGP 0.1 group). The effect depends on the dose of glyproline.Conclusions. The results obtained, based on the analysis of the free radical oxidation intensity of tissues, mainly indicate a different degree of correction of tissue homeostasis indicators. It can be assumed that Arg-Pro-Gly peptide can be the basis for the development of new drugs for post-stress rehabilitation after injuries of various levels and genesis

V-I characteristics in the vicinity of order-disorder transition in vortex matter

The shape of the V-I characteristics leading to a peak in the differential resistance r_d=dV/dI in the vicinity of the order-disorder transition in NbSe2 is investigated. r_d is large when measured by dc current. However, for a small Iac on a dc bias r_d decreases rapidly with frequency, even at a few Hz, and displays a large out-of-phase signal. In contrast, the ac response increases with frequency in the absence of dc bias. These surprisingly opposite phenomena and the peak in r_d are shown to result from a dynamic coexistence of two vortex matter phases rather than from the commonly assumed plastic depinning.Comment: 12 pages 4 figures. Accepted for publication in PRB rapi

State of rat colon microbiocenosis in chronic restraint stress treated with Selank

It is currently accepted that stress significantly affects composition of microbiocenosis due to changes in permeability of intestinal barrier and pro-inflammatory effects. This, in turn, changes behavioral reactions, anxiety and stress response. In this regard, it seems promising to use regulatory peptide-based neurotropic drugs including Selank to correct stress-induced dysbiosis. Our study was aimed at assessing state of rat colon microbiocenosis in modelled chronic restraint stress and treated with Selankby using 65 Wistar male rats divided into five groups (per 13 rats in each): group 1 — rats injected with saline; group 2 — injected with saline and induced chronic restraint stress; group 3–5 — administered with Selank at dose of 80 μg/kg, 250 μg/kg and 750 μg/kg body weight, respectively, and induced chronic restraint stress. Quantitative and qualitative study of animal colon microbiota was carried out according to the method by L.I. Kafarskaja and V.M. Korshunov. Identification of microorganisms was carried out by using a Maldi Biotyper Microflex mass spectrometer (Bruker, United States). Microbial species-specific composition was presented as lg CFU/g mass of examined sample. For each identified microbial genus, the relative mean and frequency of occurrence were calculated. Statistical significance of differences in mean values was determined by using Student’s t-test. Chronic restraint stress in the experiment did not result in affecting dominant microbiota species in rat colon nor reduce their frequency, however, it significantly influenced examined parameters for commensal microbiota disturbing pattern of pathogenic bacterial strains. Use of Selank led to the reversing changes in composition of colonic microbiocenosis caused by stress model. Moreover, magnitude of parameters examined in experiment after applying Selank at dose of 750 μg/kg reached those in non-stressed animals. Thus, effects related to Selank administration may presumably be mediated due to both central and peripheral effects including immunotropic and anti-inflammatory activities which contributed to restoring colon microbiocenosis composition in stress model

The in vitro influence of different factors on the indicators of human ejaculate

The paper presents the results of investigations dealing with the impact of experimental exposures (to chemical substances and electromagnetic radiation) on human sperm. The radiation is shown to suppress sperm motility. High hydrogen peroxide concentrations and ejaculate cryopreservation have also a negative effect on sperm motility and viability. Low hydrogen peroxide levels cause the opposite effect on sperm motility. The use of some regulatory mechanisms also yields positive results. Antioxidants increase the number of mobile sex cells in an experiment. Clinical observations using antioxidants support the results of laboratory tests

Синтез и характеристика фотоактивных арилазидных производных пептидов семакса и Pro-Gly-Pro

The photoaffine arylazide derivatives of peptides semax and Pro-Gly-Pro have been synthesized. It was shown that these compounds have cytoptotective action in culture of PC12 cells under conditions of oxidative stress.Осуществлен синтез п-азидотетрафторбензойных производных пептидов семакса и Pro-Gly-Pro. Показано, что полученные фотоаффинные арилазидные зонды обладают цтопротективным действием на культивируемые клетки PC12 в условиях окислительного процесс

Instabilities and disorder-driven first-order transition of the vortex lattice

Transport studies in a Corbino disk geometry suggest that the Bragg glass phase undergoes a first-order transition into a disordered solid. This transition shows a sharp reentrant behavior at low fields. In contrast, in the conventional strip configuration, the phase transition is obscured by the injection of the disordered vortices through the sample edges, which results in the commonly observed vortex instabilities and smearing of the peak effect in NbSe2 crystals. These features are found to be absent in the Corbino geometry, in which the circulating vortices do not cross the sample edges.Comment: 12 pages 3 figures. Accepted for publication in Physical Review Letter