Studies by (3)H-thymidin autoradiography showed that injections of Pro-Gly-Pro and Arg-Gly-Pro peptides caused no changes in the DNA synthesis processes in the gastric mucosa. Both peptides induced a reduction of free radical oxidation activity, which was shown by chemiluminescence. Indomethacin induced lesions in the gastric mucosa, triggered oxidative stress, and reduced proliferative activity. Injection of Pro-Gly-Pro peptide before indomethacin corrected disorders in oxidative status and normalized DNA synthesis. Preinjection of Arg-Gly-Pro led to enlargement (by 4.6 times) of the focus of lesions in animals treated by indomethacin and augmented oxidative stress.
Objective — To examine the morphometric parameters of neurons and the oxidative status of the Wistar rat brain tissues after administering proline-containing peptides, also known as glyprolines (Arg-Gly-Arg-Pro-Gly-Pro [RGRPGP] and Thr-Lys-Pro-Arg-Pro-Gly-Pro [WKPRPGP; Selank]), on a traumatic brain injury (TBI) model. Study subjects — Our study involved 26 mature male Wistar rats (2.5-3 mos. old, 220-300 g). The morphometric parameters of neurons and the oxidative status of animal brain tissues were studied. Material and Methods — Four experimental groups were formed. Group 1 included intact control animals. Animals in three other groups were subjected to TBI via free fall of a 50 g weight from a height of 50 cm on the second day of the experiment and received the following injections: 0.9% sodium chloride solution in Group 2; WKPRPGP peptide solution in Group 3; RGRPGP peptide solution in Group 4. Substances were administered intraperitoneally on a daily basis at a dose of 0.1 mg/kg from day 1 through day 5 of the experiment. Morphometric parameters of rat brain neurons were studied on paraffin sections stained with hematoxylin and eosin. The intensity of free radical processes in the brain tissue was investigated by chemiluminescence. Results — An analysis of morphometric parameters revealed significant increases in the neuronal cytoplasm area, nucleolar area, number of nucleoli, and nuclear-nucleolar index with the introduction of the RGRPGP peptide after TBI, compared with the WKPRPGP peptide under the same conditions. After TBI and peptide administration, we observed an oxidative stress in the neocortex of Wistar rats, and it was more pronounced in the group of animals treated with RGRPGP. Conclusion — After RGRPGP peptide administration, we observed an increase in the morphometric parameters of neurons in the closed TBI model: a larger area and a greater number of nucleoli. Chemiluminescence data implied that WKPRRPGP peptide better protected brain tissue in rats from the effects of oxidative stress caused by TBI.
Along with synthetic substances, various naturally-occurring pigments can response to pH variations in solutions by changing their colour. Such substances include, for example, anthocyanins. In this study, the possibility of applying a set of anthocyanins obtained from berry extracts as a potential acid-base indicator. This indicator can be a good alternative to the widely-used phenolphthalein test. Aqueous and alcoholic extracts derived from the fruit of ashberry, sea-buckthorn, lingonberry, blueberry, currant, blackberry, cranberry, rose hip, cherry and hawthorn plants were studied. The presence of anthocyanins in the test samples was confirmed by chemical and physicochemical methods of analysis, including qualitative tests, ascending thin-layer chromatography and direct spectrophotometry. Quantification of anthocyanins was carried out by pH-differential spectrophotometry. Compared to alcoholic extracts, aqueous berry extracts were found to contain anthocyanins in far lesser amounts. In order to compare the pH indicator potential of phenolphthalein and the studied set of anthocyanins, the content of ascorbic acid in the test samples was assessed by direct alkalimetry. A control experiment was performed using a 5% ascorbic acid solution for injection. The pH value of aqueous and alcoholic solutions of all berry extracts was determined by an instrumental procedure. The pH of the extracts ranged from 2.95 to 5.04. The content of the total amount of anthocyanins in aqueous and alcoholic extracts of blackberries, cranberries, black currants, blueberries and lingonberries in terms of cyanidin-3-glucoside was determined both quantitatively and qualitatively. A good agreement was achieved between the results of alkalimetric titration performed using phenolphthalein and the set of anthocyanins extracted from blackcurrant berries with 95% ethanol.
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.
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