Influence of carrageenan on cytokine production and cellular activity of mouse peritoneal macrophages and its effect on experimental endotoxemia.

The in vivo effect of κ/ß-carrageenan isolated from the red alga Tichocarpus crinitus on cytokine synthesis and cellular activity of murine peritoneal macrophages and also the protective effect of polysaccharides in LPS-induced endotoxemia in mice was studied. It was established that κ/ß-carrageenan given orally at a dose of 100 mg/kg stimulates the induction of anti-inflammatory cytokines (IL-10) in mouse blood cells by more than 2.5-fold compared with control, with no effect on pro-inflammatory cytokine (TNF-α) production. Pretreating mice with carrageenan once a day before injecting LPS increased the levels of IL-10 by 2.5-fold and reduced TNF-α production by 2-fold compared with control. So, κ/ß-carrageenan alone and in combination with LPS enhanced the cellular activity and mobility of peritoneal macrophages by increasing cell adhesion and migration compared with control. LPS activated cells intensively, sometimes resulting in their destruction by necrosis; carrageenan pretreatment reduced the excessive inflammatory cell activation caused by LPS. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 1549-1557, 2017.

Carrageenans effect on neutrophils alone and in combination with LPS in vitro.

Influence of sulfated red algal polysaccharides (κ-, λ-, and κ/ß-carrageenans) and degraded derivative of κ/ß-carrageenan on neutrophils/monocytes activation alone and in combination with lipopolysaccharide was investigated by means of determination of reactive oxygen species production, latex microparticles engulfment, total and extracellular myeloperoxidase induction and the analysis of silhouette and contour two-dimensional images of flattened cells. Carrageenans alone can activate neutrophils with much less potency than lipopolysaccharide (LPS) and the sulfation degree of carrageenans stipulates high activity in this role. On the other hand, carrageenans especially with low contents of sulfate groups are able to interfere with LPS in vitro resulting in reducing inter- and intracellular activation of neutrophils killing mechanisms. Further research is necessary to relate these findings to actions on the whole animal or human in vivo. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 1603-1609, 2016.

[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.

[Chitosan antiviral activity: dependence on structure and depolymerization method].

Enzymatic (the action of lysozyme) and chemical (hydrogen peroxide) hydrolysis of chitosans with various degree ofacetylation (DA)--25, 17, and 1.5%--was performed. Purification and fractioning of the hydrolysis products were performed using dialysis, ultrafiltration, and gel-penetrating chromatography Low-molecular (LM) derivatives of the polysaccharide with molecular masses from 17 to 2 kDa were obtained. The study of their antiviral activity against the tobacco mosaic virus (TMV) showed that these samples inhibited the formation of local necroses induced by the virus for 50-90%. The antiviral activity of the LM chitosans significantly increased with the lowering of their polymerization degree. Furthermore, the products of the enzymatic hydrolysis possessed higher activity than the chitosan samples obtained as a result of chemical hydrolysis. It was revealed that the exhibition of the antiviral activity weakly depended on the degree of acetylation of the samples.