BioMedicine Volume 11 Issue 3 Article 4 2021 Konjac glucomannan polysaccharide and inulin oligosaccharide ameliorate dextran sodium sulfate-induced colitis and alterations in fecal microbiota and short-chain fatty acids in C57BL/6J mice Follow this and additional works at: https://www.biomedicinej.com/biomedicine Part of the Life Sciences Commons, and the Medical Sciences Commons This work is licensed under a Creative Commons Attribution 4.0 License. Recommended Citation Changchien, Chih-Hsuan; Wang, Cheng-Hsin; and Chen, Hsiao-ling (2021) "Konjac glucomannan polysaccharide and inulin oligosaccharide ameliorate dextran sodium sulfate-induced colitis and alterations in fecal microbiota and short-chain fatty acids in C57BL/6J mice," BioMedicine: Vol. 11 : Iss. 3 , Article 4. DOI: 10.37796/2211-8039.1191 This Original Articles is brought to you for free and open access by BioMedicine. It has been accepted for inclusion in BioMedicine by an authorized editor of BioMedicine. Konjac glucomannan polysaccharide and inulin oligosaccharide ameliorate dextran sodium sulfate-induced colitis and alterations in fecal ORIGINAL ARTICLE microbiota and short-chain fatty acids in C57BL/6J mice Chih-Hsuan Changchien 1,2, Cheng-Hsin Wang 3, Hsiao-Ling Chen 4,5,* 1 Department of Medical Laboratory Science and Biotechnology, Asia University, Taiwan 2 Department of Plastic and Reconstructive Surgery, Ditmanson Medical Foundation Chia-Yi Christian Hospital, Taiwan 3 Department of Food and Nutrition, Providence University, Taiwan 4 Department of Food, Nutrition and Health Biotechnology, Asia University, Taiwan 5 Department of Medical Research, China Medical University Hospital, China Medical University, Taiwan Abstract Background: Konjac glucomannan polysaccharide (KGM), inulin oligosaccharide (inulin) and their mixture has been shown to modulate the gut-associated lymphoid tissue immunity. Aims: The present study was mainly to determine effects of a low-level (2% w/w) KGM and inulin and their com- bination on dextran sodium sulfate (DSS)-induced colitis. We also determine the potential mechanisms mediating these effects of dietary fibers. Methods: C57BL/6J mice (6 weeks of age, eight per group) were randomly assigned to consume one of the following diets: control (DSS group) or control diet supplemented with 2% (w/w) of KGM (KGM group), 2% (w/w) of inulin oligosaccharide (inulin group) or KGMþInulin (1%, w/w each (KþI group)) for 29 days, combined with the DSS drinking water (2% w/v) treatment on days 21-26. Another group served as vehicle was fed the control diet and given regular drinking water throughout the study. Fresh feces were collected on days 26-29. Mice were killed on day 30 after fasting. Segments of distal colon were processed for histological procedure. The remaining colonic tissues were pro- cessed to determine the colonic gene expressions of cytokines, tight junction proteins and antioxidant enzymes. Results: The present study indicated that DSS resulted in colonic dysplasia, severe leukocyte infiltration and enhanced gene expressions of pro-inflammatory cytokines. All fiber treatments ameliorated these indices of colitis. DSS treatment reduced the colonic gene expressions of tight junction proteins and antioxidant enzymes, which were ameliorated or normalized with fiber supplementation. In addition, all fiber treatments prevented the DSS-induced alterations in the fecal microbiota and short-chain acid levels. Conclusion: Supplementation of low-level, 2% (w/w), of KGM polysaccharide, inulin oligosaccharide and K þ I reduced the DSS-induced colitis and mucosal barrier dysfunction, which was likely to be mediated by the prebiotic effects. Keywords: Colitis, Dextran sulfate sodium, Konjac glucomannan, Inulin, Microbiota, Mucosal barrier Introduction incidence and prevalence of IBD were the highest in western countries [2]. The reported annual he ulcerative colitis is an inflammatory incidence of ulcerative colitis was 24.3 and 19.2 T bowel disease (IBD) that occurs in the colon per 100,000 person-years in Europe and North [1]. Epidemiological studies found that the America, respectively [2]. The incidence is still Received 7 January 2021; revised 13 February 2021; accepted 17 February 2021. Available online 1 September, 2021. * Corresponding author at: Department of Food, Nutrition and Health Biotechnology, Asia University, No. 500, Lioufeng Rd., Taichung, Taiwan. Fax: þ886 4 23321215. E-mail address: [email protected] (H.-L. Chen). https://doi.org/10.37796/2211-8039.1191 2211-1191/Published by China Medical University 2021. © the Author(s). This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). 24 C.-H. CHANGCHIEN ET AL BioMedicine DIETARY FIBER AMELIORATES COLITIS-ASSOCIATED COLONIC DYSFUNCTION 2021;11(3):23e30 ORIGINAL ARTICLE arising in low-incidence areas such as Asia and microbial fermentation products short-chain fatty developing countries [2]. The pathogenesis of IBD acids and stimulate the growth of bifidobacteria and is multifactorial, involving mucosal barrier de- lactobacilli in animal/human studies [14,16-18]. fects, dysregulated immune responses, genetic KGM and inulin modulate the colonic antioxidant system and increased the antioxidant defense predisposition and environmental factors [3]. against the oxidative stress resulted from a low-fiber The mucosal barrier consists of mucosal layer, tight high-fat diet or a genotoxic carcinogen [18-20]. In junction and microflora, which protects the body addition, a previous study indicated that either from potential pathogens [4]. The tight junctions form KGM or inulin oligosaccharide could effectively the continuous intercellular barrier between the in- strengthen the colonic mucosal barrier and increase testinal epithelial cells is required to separate tissue the expressions of tight junction proteins occludin (a spaces, regulate selective movement of solutes across transmembrane barrier protein) and zone occludin- the epithelium and maintain the mucosal barrier 1 (ZO-1) (a peripheral scaffolding protein) [18]. function [4]. The reduced expression of tight junction These fibers also modulate gut immunity by protein may lead to translocation of endotoxins and increasing the colonic gene expression of IL-10, an bacterial antigens and causes excessive inflammation anti-inflammatory cytokine [16]. However, effects of in the gut-associated lymphocyte tissue [4]. KGM and the combination of KGM and inulin The colonic mucosa is constantly challenged by oligosaccharide on prevention of ulcerative colitis the reactive oxidative substances produced from the have never been examined. microbiota and lumen contents [5]. An imbalanced Dextran sodium sulfate (DSS) causes colonic in- cellular redox system of mucosa results excess testinal epithelial cell injury and has been used to reactive oxidative substance levels and subse- induce experimental colitis [21,22]. The present quently causes gastrointestinal tract inflammation study was undertaken to investigate effects of KGM, [5,6]. In addition, activated leukocytes during the inulin oligosaccharide and their mixture on the active phase of inflammation generate reactive colonic inflammation, tight junction proteins, anti- oxidative reactions that further impairs the mucosal oxidative enzymes, fecal microbiota and short-chain barrier [7]. Therefore, oxidative stress is considered fatty acids in a DSS-induced colitis mouse model. In to play an important role in the mucosal damage in order to be applicable to humans, the level of fiber IBD [5]. For examples, previous studies indicated supplementation was only 2% w/w, which is increased peroxidative products in both the ulcera- equivalent to 10 g/d of normal human diet. tive colitis mouse model and IBD patients [8,9]. Current medical treatments for IBD include corti- Methods costeroids, antibiotics, 5-aminosalicylic acid, immu- nomodulator and biological therapies [10]. Animals Traditional therapy may cause side effects due to immune-suppression [11]. Therefore, the need for Male C57BL/6J mice were purchased at 5 weeks of complementary and alternative medicine approaches age from the National Laboratory Animal Breeding for prevention and treatment of IBD is increasing [12]. and Research Center (Taipei, Taiwan). Animals Konjac glucomannan (KGM) is a viscous soluble were housed in a solid-bottomed plastic cage with fiber isolated from the underground tuber of stainless wire bar lid and wood shavings for Amorphophallus konjac [13]. It is composed of b-1, 4- bedding in an animal holding room maintained on a linked D-glucose and D-mannose units joined 12-h light/dark cycle at 24 ± 1C and 50 ± 2% hu- together with branches through b-1,6-glucosyl units midity. All animals were allowed free access to [13]. The KGM has been processed into various water and food in the present study. The care and vegetarian food products commonly consumed in use of animals was in accordance with European the Asian countries. Inulin, found in the under- Commission Directive 86/609/EEC for animal ground tuber of chicory (Cichorium intybus), is an experiment [23] and the guidelines of the National oligomer or polymer of b-D-fructose containing two Research Council [24]. All experimental procedures to mostly sixty monomeric units that are linked by involving animals were approved by the Institu- b-(2 / 1) glycosidic bridges [14]. The fraction of tional Animal Care and Use Committee. inulin with the degree of polymerization lower than 10, namely, inulin oligosaccharide, is widely used as Experimental