Anti-Inflammatory Activity of Oat Beta-Glucans in a Crohn’s Disease Model: Time- and Molar Mass-Dependent Effects

Abstract

Background: The incidence of Crohn’s disease (CD) is increasing worldwide, and it has currently become a serious public health issue in society. The treatment of CD continues throughout a patient’s lifetime, and therefore, it is necessary to develop new, effective treatment methods, including dietotherapy. The present study aimed to determine the effects of consumption of oat beta-glucans with different molar mass on colon inflammation (colitis) in the early stages of 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced CD in an animal model. Methods: Sprague–Dawley rats (control and TNBS-induced CD) were divided into three dietary groups and fed for 3 days (reflecting acute inflammation) or 7 days (reflecting remission) with a feed containing 1% low (βGl) or high (βGh) molar mass oat beta-glucan or a feed without this polysaccharide. The level of colon inflammatory markers and the expression of cytokines and their receptor genes were measured by ELISA and RT-PCR methods, respectively. Results: Acute inflammation or remission (3 or 7 days after TNBS administration, respectively) stages of experimentally induced CD were characterized by an increase in the level of inflammatory markers (IL-1, IL-6, IL-10, IL-12, TNF-α, CRP, MPO, COX, and PGE2) and the disruption of some cytokine signaling pathways as well as macro- and microscopic changes of colon tissue. The consumption of oat beta-glucans reduced the level of inflammatory markers and recovered the signaling pathways and histological changes, with stronger effects of βGl after 7 days of colitis. Conclusions: Dietary oat beta-glucans can reduce colitis at the molecular and organ level and accelerate CD remission.

Colon Expression of Chemokines and Their Receptors Depending on the Stage of Colitis and Oat Beta-Glucan Dietary Intervention—Crohn’s Disease Model Study

“…In addition, our study analyzed the influence of beta-glucans on the gene expression of important proteins involved in the pathogenesis of IBD. The results of this study, as well as that of the previously published works, confirm the immunomodulatory properties of both oat beta-glucan fractions [32,44,47]. However, high-molar-mass oat beta-glucan showed a stronger effect on the analyzed parameters and decreased the gene expression of Ccl3, Ccl4, Cxcl1, Cxcl2, Ccr1, Ccr2, Ccr5, Cxcr2, Osm, Csf3, and Spp1 in acute inflammation of the colon wall, and the gene expression of Ccl5, Cxcl1, Cxcl2, Cxcl11, Ccr2, Ccr5, Cxcr2, and Spp1 in the preremission phase (Table 1).…”

“…This effect is related to a faster and more intense immune response to the damage of the intestinal barrier caused by the rectal administration of TNSB. Our previously published results confirmed the accelerated remission and a milder course of inflammation in rats with colitis [32,39,44]. Interestingly, earlier studies have shown that neutrophils may also play a protective role during TNBS-and DSS-induced colitis [45,46].…”

“…The recruited immune cells increase the expression of proinflammatory cytokines, which in turn recruit new immune cells and enhance the immune response [31]. Our previous results showed that supplementation of feed with oat beta-glucans significantly modulated the expression of the genes involved in the signaling pathways of cytokines and their receptors [32]. The present study showed that oat beta-glucans influenced the expression of chemokines and their receptors, which are considered integral components and regulators of inflammation as they serve as chemoattractants, recruiting immune cells to the site of inflammation.…”

“…In our study, the consumption of low-or high-molar-mass oat beta-glucans reduced the gene expression of some of the chemokines and their receptors, especially after 3 days of colitis induction. After 3 days, the colon inflammation in rats was found to be of acute local type, with a large increase in the gene expression of chemokines and their receptors as well as in the expression of proteins and/or genes of cytokines and their receptors and other markers of inflammation, with slight changes in the blood parameters [32,39]. After 3 days of colitis induction, reduced expression of genes such as Ccl3 and Ccl4 and that of chemokine receptors Ccr1 and Ccr2 was observed in colitis animals receiving feed supplemented with low-molar-mass oat beta-glucan, while the animals receiving feed with high-molar-mass beta-glucan showed decreased expression of the chemokines Ccl3, Ccl4, Cxcl1, and Cxcl2 and the receptors Ccr1, Ccr2, Ccr5, and Cxcr2.…”

Multiple Antioxidative and Bioactive Molecules of Oats (Avena sativa L.) in Human Health

“…β-glucan regulates the gastrointestinal transit rate after meals and starch digestion to dilute blood sugar level through changes in the glycemic index, thereby reducing the insulinemic response in diabetes [ 41 , 45 ]. In addition, β-glucan has various physiological effects such as preventing cardiovascular diseases by controlling the blood pressure and anti-obesity and anti-cancer effects (e.g., prevention of colorectal cancer) [ 18 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 ]. It lowers low-density lipoprotein (LDL) cholesterol level in the blood and elevates high-density lipoprotein (HDL) cholesterol level to help maintain normal blood lipid concentration and body weight [ 56 ].…”