[Low level laser therapy: molecular mechanisms of anti-inflammatory and regenerative effects]. / Nizkointensivnaya lazernaya terapiya: molekulyarnye mekhanizmy protivovospalitel'nogo i regenerativnogo effektov.

Laser therapy as a physiotherapeutic method has been successfully used for a long time in the treatment of various pathologies, but the action mechanisms of low level laser therapy (LLLT) remain understudied. OBJECTIVE: To perform the analysis of published results of LLLT investigations, to describe the physical principles of photobiomodulation, its action mechanisms on various cells and tissues, therapeutic intervention and efficiency of the technique. MATERIAL AND METHODS: The search of articles was done for the period from 2014 to 2022. The preference was given to the articles for the last 5 years in the PubMed database depending on keywords: low level laser therapy, photobiomodulation, exosomes, monocytes, macrophages. RESULTS AND DISCUSSION: This article represents the current conceptions about the action mechanisms and reproduced effects of low level laser therapy, the photobiomodulation influence on the inflammation and reparative processes in human body by intervention on cells and their signal pathways. The discussion of research results and probable causes of conflicting data are performed, as well as the efficacy assessment of laser irradiation in different conditions and diseases is made. CONCLUSION: Laser therapy has certain variety of advantages, among which: non-invasiveness and availability, long-term service of equipment, stable intensity of light radiation and the ability to use in various wavelength ranges. The technique efficacy was proven for a large number of diseases. However, for the successful application of photobiomodulation in clinical practice in current evidence-based medicine, additional investigations are necessary to determine the best dosimetric radiation parameters, as well as further study of action mechanisms on various human cells and tissues.

[Gastroprotective and antidepressant-like effect of plum pectin (Prunus domestica L.) under water-immobilization stress in laboratory mice].

Stress effects activate the processes of free radical oxidation in the organism, lead to hyper production of reactive radicals and oxidative stress, provoking the development of an inflammatory process in various parts of the gastrointestinal tract. Pectin polysaccharides together with the enzyme components of the endogenous antioxidant system contribute to the elimination of the imbalance between prooxidants and antioxidants in the tissues of stressed animals and have a gastroprotective and antidepressant-like effect. The aim of the research was to evaluate the gastroprotective, antioxidant and antidepressant-like effect of plum pectin orally administered to white laboratory mice before stressful exposure. Material and methods. In the experiment on white BALB/c mice weighing 20-25 g (90 males, 10 in each group), pectin isolated from fresh plum fruits in an artificial gastric environment was used. It was administered orally to mice 24 h before the onset of stress exposure or behavioral activity asessment. 50 animals were subjected to 5 h of water immersion stress. After this corticosterone concentration in blood plasma, and the activity of superoxide dismutase, catalase and glutathione peroxidase in the tissue supernatants of the gastrointestinal tract were determined, and the condition of the gastric mucosa was also assessed. Behavioral activity of experimental mice (n=30) was assessed in the open field and forced swimming tests. Results. The stress effect was accompanied by an increase in plasma corticosterone concentration (more than 3 fold), in the activity of superoxide dismutase, glutathione peroxidase in the tissues of the stomach wall and small intestine (17.9-28.6%) and destructive damage in the gastric mucosa compared with the indices of intact animals. Preliminary oral administration of plum pectin to animals at a dose of 80 mg per 1 kg of body weight helped to reduce the level of corticosterone and the number of stress-induced hemorrhages on the gastric mucosa, normalized the activity of antioxidant enzymes and also decreased the immobility time of mice in the forced swimming test. Preliminary oral administration of plum pectin to animals at a dose of 80 mg per 1 kg of body weight prevented an increase in the activity of antioxidant enzymes, corticosterone in the blood and the development of stress-induced hemorrhages on the gastric mucosa, and reduced the time of immobility of mice in the forced swimming test. Conclusion. Plum fruit pectin pre-administered into mice before stress prevents stress-induced damage in the tissues of the gastrointestinal tract, contributing to an increase in the body's resistance to the stress factor. Plum pectin has an antioxidant, gastroprotective and antidepressant-like effect and can be used as an ingredient in functional foods that reduce the risk of inflammatory diseases of the gastrointestinal tract under stress.

[Anti-inflammatory activity of high and low methoxylated apple pectins, in vivo and in vitro].

One of the possible mechanisms of the anti-inflammatory action of pectins is associated with the inhibition of excessive pro-inflammatory activity of macrophages - the cells that regulate inflammation intensity and reparative regeneration. It has been found that pectins with a low degree of methyl esterification of the carboxyl groups of the galacturonan core of the macromolecule exhibit this effect. In addition to leukocytes, intestinal epithelial cells are also involved in the pathogenesis of inflammatory bowel diseases. However, to date, there have been insufficient studies of the effect of pectin methyl esterification on the inflammatory response of enterocytes. The aim of the research was to evaluate the effect of the degree of pectin methyl esterification on inflammation of the colon in mice after oral administration and on the inflammatory response of human colon epithelium cells of the Caco-2 line in vitro. Material and methods. In a prospective study, 40 male BALB/c mice weighing 20-25 g were used, 10 animals in each group. Solutions of apple pectins (200 mg/0.2 ml) were orally administered to mice through a plastic catheter 24 h before the induction of colitis. The control mice received water, and prednisone administration at a dose of 5 mg/kg of body weight was used as a positive control. Colon inflammation in mice was induced by a single rectal administration of 5% acetic acid (0.1 ml). A day later, the degree and area of the lesion was assessed using a light microscope, the activity of myeloperoxidase in the wall of the colon was determined by spectrophotometry. The effect of pectins on metabolic activity, intercellular permeability, Tumor Necrosis Factor α generation and alkaline phosphatase (ALP) activity in Caco-2 cells was assessed. Results. It was found that low-methyl esterified pectin AU701, which contains more than 70% of free carboxyl groups, inhibited colon inflammation in mice. High methyletherified pectin AU201, in which more than 70% of the carboxyl groups are replaced by methyl ester, didn't affect inflammation. It was revealed that pretreatment of Caco-2 cells with AU701 and AU201 pectins prevented lipopolysaccharide-induced increase in intercellular permeability and reduced the pro-inflammatory response of Caco-2 cells to LPS. After incubation of Caco-2 cells with AU701 pectin, the rate of hydrolysis of p-nitrophenyl phosphate (an alkaline phosphate substrate) increased by 40%. Pectin AU201 had no effect on the alkaline phosphatase activity of enterocytes. Conclusion. Thus, it was found that low-methyl esterified pectin AU701 inhibits inflammation both in vivo and in vitro. High-methyl esterified pectin AU201 suppresses pro-inflammatory reactions only in vitro. The ability of pectins to inhibit intestinal inflammation has a multifactorial nature, and is due, inter alia, to their ability to stimulate the expression of alkaline phosphatase by enterocytes.

[The effect of agar-pectin gels on the eating behaviour of fasted and fed mice].

A diet rich in non-digestible plant polysaccharides (dietary fibers) leads to effective appetite suppression and reduces food intake. The mechanical properties of food contribute to the satiating effect of food. It is known that solid food satiates to a greater extent than liquid, as the duration of food processing in the oral cavity increases. The aim of the study was to assess the effect of mechanical properties of agar-pectin gels on the feeding behaviour of mice Material and methods. The gels were prepared by dissolving the corresponding weights of agar, pectin and sucrose in 100 ml of water: gel 1 contained 6 g of agar, 3 g of pectin, gel 2 - 20 g of agar, 1 g of pectin and 0.03 M CaCl2, gel 3 - 20 g of agar, 1 g of pectin (without the addition of calcium ions). All gels contained an equal amount of sucrose (15 g per 100 ml of water). The mechanical properties of the gels (strength, Young's modulus and elasticity) were determined on a texture analyzer. Mice with an initial body weight of 32.9±0.5 g (n=8 in each group) received gels once a day for four days. Each day, animals were individually placed in experimental cages for 60 minutes: in the first 30 min, they were given test gels and for the next 30 min standard rodent food. The first two days were training. Before the third gel presentation, the animals were previously completely restricted in food for 14 hr (fasted mice), and before the fourth gel presentation, the mice received food ad libitum (fed mice). The eating behaviour of the mice, the amount of gel eaten and standard feed eaten were determined. Mice that were not exposed to gels were used as control. Results and discussion. Gel 3 was the hardest (251±3 kPa) in comparison with gel 1 (44±1 kPa) and 2 (141±3 kPa). Fasted mice that received gel 3 ate 36% less food (p<0.05), and the total energy intake was 19% lower (p<0.05) compared to the control. Fasted mice that received gels 1 and 2 ate the same amount of food as the control animals. Gel 3 significantly reduced feeding time by 19% (p<0.05) in fasted mice. Gels 1 and 2 did not alter the eating behaviour of fasted mice. Fed mice that received gels ate as much food as in the control. Gels failed to affect the eating behaviour of fed mice. Conclusion. Overall, solid gel 3 reduced food intake and time spent on feeding after 14 h of complete food restriction. The effect of the gel on the feeding behaviour of animals and the amount of food eaten is determined by the hardness of the gel and does not depend on the ratio of the components of the gel and its resistance to in vitro simulated gastric and intestinal fluids.

[Cytokine-inducing and anti-inflammatory activity of chitosan and its low-molecular derivative].

A low-molecular derivative of the polysaccharide (5 kDa) was obtained and its cytokine-inducing and anti-inflammatory activity was studied by free radical depolymerization of chitosan (110 kDa). It was shown that high-molecular chitosan in vitro inhibited the synthesis of anti-inflammatory cytokine, the tumor necrosis factor alpha induced by endotoxin. In the case of peroral introduction to experimental animals, high- and low-molecular chitosans stimulated synthesis of the anti-inflammatory cytokine IL-10 in the blood serum of mice; in this case, the activity of the high-molecular derivative was two times higher as compared with the initial polysaccharide. With peroral introduction, the initial polysaccharide (50 mg/kg) and its derivative inhibited the development of chemically induced inflammation of experimental animals' large intestines, which was manifested as a decrease in the affected area and the degree of damage to the large intestine wall, as well as a two-fold reduction of myeloperoxidase activity. According to morphological and biochemical characteristics, the effect of chitosans was similar to that of a hormone anti-inflammatory drug, prednisolone.

Chemical characterization and anti-inflammatory effect of rauvolfian, a pectic polysaccharide of Rauvolfia callus.

The pectic polysaccharide named rauvolfian RS was obtained from the dried callus of Rauvolfia serpentina L. by extraction with 0.7% aqueous ammonium oxalate. Crude rauvolfian RS was purified using membrane ultrafiltration to yield the purified rauvolfian RSP in addition to glucan as admixture from the callus, with molecular weights 300 and 100-300 kD, respectively. A peroral pretreatment of mice with the crude and purified samples of rauvolfian (RS and RSP) was found to decrease colonic macroscopic scores, the total area of damage, and tissue myeloperoxidase activity in colons as compared with a colitis group. RS and RSP were shown to stimulate production of mucus by colons of the colitis mice. RSP appeared to be an active constituent of the parent RS. The glucan failed to possess anti-inflammatory activity.