03. Науково-дослідний інститут експериментальної та клінічної медицини ХНМУ

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Browsing 03. Науково-дослідний інститут експериментальної та клінічної медицини ХНМУ by Author "Nakonechna, Oksana"

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    Changes in cell membranes of white blood cells treated with a common food additive E407a
    (2021) Tkachenko, Anton; Onishchenko, Anatolii; Posokhov, Yevgen; Roshal, Alexander; Myasoedov, Valeriy; Nakonechna, Oksana
    Objectives: To estimate the state of phospholipid bilayer of rats WBCs exposed to a common food additive E407a, which is used as a thickener and emulsifier, during 4 h using a fluorescent probe − ortho-hydroxy derivative of 2,5-diaryl-1,3-oxazole. Materials and methods: Steady-state fluorescence spectroscopy: a study by the environment-sensitive fluorescent probe − 2-(2′-hydroxy-phenyl)-5-phenyl-1,3-oxazole (probe O1O). Results: Changes are detected in the spectra of the fluorescent probe bound to rat WBCs treated with the solutions of E407a of various concentrations in comparison with the corresponding spectra of the probe incubated with the untreated leukocytes. The decrease in polarity and protondonor ability is observed in the lipid membranes of leukocytes in the region, where the probe locates. Conclusions: Our findings suggest a higher dehydration of leukocyte membranes of rats treated with a common food additive E407a at high concentrations and, thus, indicate that exposure to high doses of E407a leads to the increase in the lipid order (i.e. to decrease in fluidity) of the membranes of rat WBCs.
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    Effects of semi-refined carrageenan (food additive E407a) oncell membranes of leukocytes assessed in vivo and in vitro
    (2021) Tkachenko, Anton; Onishchenko, Anatolii; Roshal, Alexander; Nakonechna, Oksana; Chumachenko, Tetyana; Posokhov, Yevgen
    Aim: To assess the impact of semi-refined carrageenan (E407a) on hydrophobic regions of phosphololipid bilayer in cell membranes of leukocytes collected from rats orally administered this food additive and white blood cells incubated with E407a. Methods: Fluorescent probes (ortho-hydroxy derivatives of 2,5-diaryl-1,3-oxazole) were used to estimate the state of lipid bilayer in leukocytes obtained from rats orally exposed to the food additive E407a and in white blood cells incubated with E407a. Results: No noticeable changes in the physico-chemical properties were observed in the lipid membranes of leukocytes in the region where the probes locate in response to oral intake of semi-refined carrageenan. Incubation of leukocytes with E407a solutions resulted in a decrease in polarity and proton-donor ability of leukocytes in the area of carbonyl groups of phospholipids and in the area of hydrocarbon chains of phospholipids near the polar region of the bilayer. Conclusion: Membrane fluidity abnormalities found in cells exposed to E407a are similar to those observed in patients with IBD suggesting that contribution of carrageenan to IBD development may be partially explained by leukocyte membrane modifications.
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    Experimental Evaluation of Food-Grade Semi-Refined Carrageenan Toxicity
    (2021-10-16) Pogozhykh, Denys; Posokhov, Yevgen; Myasoedov, Valeriy; Gubina-Vakulyck, Galina; Chumachenko, Tetyana; Knigavko, Oleksandr; Polikarpova, Hanna; Kalashnyk-Vakulenko, Yuliia; Sharashydze, Ketino; Nakonechna, Oksana; Prokopyuk, Volodymyr; Onishchenko, Anatolii; Tkachenko, Anton
    Abstract: The safety of food additives E407 and E407a has raised concerns in the scientific community. Thus, this study aims to assess the local and systemic toxic effects of the common food additive E407a in rats orally exposed to it for two weeks. Complex evaluations of the effects of semi-refined carrageenan (E407a) on rats upon oral exposure were performed. Local effects of E407a on the intestine were analyzed using routine histological stains and CD68 immunostaining. Furthermore, circulating levels of inflammatory markers were assessed. A fluorescent probe O1O (2- (20-OH-phenyl)-5-phenyl- 1,3-oxazole) was used for evaluating the state of leukocyte cell membranes. Cell death modes of leukocytes were analyzed by flow cytometry using Annexin V and 7-aminoactinomycin D staining. Oral administration of the common food additive E407a was found to be associated with altered small and large intestinal morphology, infiltration of the lamina propria in the small intestine with macrophages (CD68+ cells), high systemic levels of inflammation markers, and changes in the lipid order of the phospholipid bilayer in the cell membranes of leukocytes, alongside the activation of their apoptosis. Our findings suggest that oral exposure to E407a through rats results in the development of intestinal inflammation.