The daily topical application of two compounds, a cream containing 10% evening primrose oil (EPO) and Lioxasol (a compound used clinically to treat radiation burns), resulted in increased cell proliferative activity in the skin of female Large White pigs. The effect was most pronounced in the case of the EPO based cream, and was comparable in magnitude with that observed in a previous study on pig skin using orally administered EPO. There was an increase in the size of the rete pegs in the epidermis by 6 weeks after the start of application of the EPO cream. However, this did not translate into an increase in the total thickness of the viable epidermis (excluding the stratum corneum) due to a reduction in the density of rete pegs, from 2 weeks after treatment. Lioxasol had no overall effect on the size of the rete pegs. The labelling index (LI) of cells in the basal layer of the epidermis of pigs receiving a daily topical application of EPO increased progressively with time from the start of application. The LI was maximal (17.9 +/- 2.4%) at the end of the observation period (8 weeks) at which time it was a factor of approximately 2 higher than in the basal layer prior to treatment. A considerably less marked increase in the LI of the basal layer was seen after the application of Lioxasol. The overall increase was approximately 20%, relative to the LI in the untreated epidermis. Labelled cell nuclei were also counted in the papillary dermis. After the application of the EPO cream, no significant increase in the number of labelled cells was observed until week 8, at which time values were approximately twice those in untreated skin. In Lioxasol treated skin the effect on the numbers of labelled cells in the papillary dermis was more immediate, with a approximately 60% increase at 2 weeks. This enhanced level of labelling was maintained until the end of the observation period of 10 weeks. Studies on the cell kinetics of the skin using the alcohol component of the Lioxasol preparation suggested that alcohol rather than Lioxasol was the most significant ingredient. It was concluded that the EPO cream merited further evaluation as a potential modulator of skin response to ionizing radiation.
Objective ― to evaluate the role of the amino acid arginine in the structure of the non-opioid analogue of leu-enkephalin (NALE) and the involvement of the nitric oxide system in the implementation of its cardioprotective effect in newborn albino rats subjected to intrauterine hypoxia. Material and Methods ― Pregnant female rats were subjected daily to 4-hour hypobaric hypoxia (oxygen partial pressure – 65 mm Hg) on days 15-19 of their gestation. The 7-day-old offspring of hypoxified female rats were examined. The progeny of intact animals served the control. We studied body and heart weights; activity of proliferative processes and autophagy in the myocardium of subendocardial parts of the left ventricle, expressed via the immunohistochemical detection of Ki-67 and Beclin-1 proteins, respectively; karyometric and nucleolometric indicators of cardiomyocytes (CMC); intensity of free radical processes in the tissues of the heart by chemiluminescence parameters. Correction of post-hypoxic changes in newborn rats was carried out by intraperitoneal injection of two peptides (Phe–D-Ala–Gly–Phe–Leu–Arg – non-opioid analogue of leu-enkephalin, or NALE, and Phe–D-Ala–Gly–Phe–Leu–Gly – G peptide) daily from day 2 through day 6 of their lives at a dose of 100 μg/kg. To assess the involvement of the nitric oxide system in the implementation of the NALE effects, the NO synthase inhibitor – N-nitro-L-arginine methyl ester (L-NAME) was additionally administered at a dose of 50 mg/kg. Results ― Intrauterine hypoxia led to a decrease in body weights of 7-day-old animals, an increase in the number of CMC expressing the Beclin-1 protein, reduction in the size of CMC nuclei, activation of free radial oxidation, and a decrease in antiradical protection in the heart tissues. The administration of NALE to newborn animals, subjected to intrauterine hypoxia (IUH), normalized their body weight and size of the CMC nuclei, and partially corrected changes in Beclin-1 expression and in chemiluminescence parameters. In 7-day-old animals, subjected to IUH and neonatal administration of NALE and L-NAME, a lower body weight was observed than in the control. Against the background of nitric oxide blockade, the antioxidant effect of NALE diminished, but the corrective effect of NALE on the karyometric index and Beclin-1 expression remained. G peptide, which differs from NALE by the substitution of the C-terminal amino acid Arg for the amino acid Gly, exhibited a corrective effect similar to NALE on the consequences of IUH. Conclusion ― Administration of NALE and G peptides to newborn albino rats after IUH has a pronounced cardioprotective effect. The mechanisms of the NALE peptide effects are, in part, associated with the activation of the NOS-NO system. However, the affinity of this peptide for opioid-like receptors may be of greater importance.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.