Konjac glucomannan polysaccharide and inulin oligosaccharide enhance the colonic mucosal barrier function and modulate gut-associated lymphoid tissue immunity in C57BL/6J mice

Abstract

Both konjac glucomannan (KGM) and inulin oligosaccharide have been shown to improve bowel function, but their effects on the mucosal barrier function and immunity are not fully understood. The aim of the present study was to determine the effects of a low-level supplementation of dietary fibres on the colonic mucosal barrier function, antioxidant enzyme defence and immunity. C57BL/6J mice (6 weeks of age, eight per group) were randomly assigned to consume one of the following diets: control or control diet supplemented with 2 % (w/w) of KGM, inulin oligosaccharide (degree polymerisation = 8) or KGM+inulin (1 %, w/w each (K+I)). Fresh faeces were collected on days 19–21. Mice were killed on day 22 after fasting. Segments of colon tissues were processed for histological procedure and stained for acidic mucins and tight junction protein marker zona occludin-1 (ZO-1). The remaining tissues were processed to determine the gene expression of mucin 2, tight junction proteins, antioxidant enzymes and cytokines. The plasma cytokines were measured. Results indicated that KGM, inulin and K+I significantly increased the mucosal layer thickness, mucin density (granule number/crypt) and gene expression of Muc2 as compared with the control. All fibre treatments increased the gene expressions of ZO-1, occludin, glutathione peroxidase, glutathione S-transferase π, catalase and IL-10. In addition, all fibre treatments increased faecal butyrate and probiotics, and plasma IL-10 concentrations. In conclusion, supplementation of low-level, 2 % (w/w), of K+I was sufficient to enhance the mucosal barrier function and anti-inflammatory status.

A Purified Glucomannan Oligosaccharide from Amorphophallus konjac Improves Colonic Mucosal Barrier Function via Enhancing Butyrate Production and Histone Protein H3 and H4 Acetylation

“…The intestinal mucus layer is constantly replenished via the secretory activity of goblet cells . Although both KGM and KGM oligosaccharides have been reported with protective effects on the colonic mucus layer, ,, the molecular mechanism for this is mostly unclear. To gain better insights into the effects of KGM oligosaccharides on intestinal function and provide a reference for related studies in vivo, the intestinal architectural changes upon KGMOS treatment were investigated.…”

“…Short-chain fatty acids extracted from colonic fecal samples by diethyl ether were determined using a gas chromatograph (GC-2014, Shimadzu, Kyoto, Japan) connected with a glass capillary column and a flame ionization detector as reported previously …”

Comparative effects of different enzymatic hydrolysates of konjac glucomannan on gut flora and constipation in rats

“…27 Furthermore, supplementation of sufficient KGM could enhance the mucosal barrier function and anti-inflammatory status. 28 In recent years, emerging evidence has suggested that dietary fiber could noticeably attenuate constipation by modulating the expression of aquaporin. 29 However, this study might provide instructive reference for the comparative study of promoting gastrointestinal motility, mucous secretion, and gut probiotic microbiota, except for the mechanisms of regulating liquid water metabolism.…”

Intestinal Mucosal Barrier Improvement with Prebiotics: Histological Evaluation of Longish Glucomannan Hydrolysates-Induced Innate T Lymphocyte Activities in Mice

“…Hemicelluloses such as popular glucomannan (also called ‘konjac’) are usually considered prebiotics [ 16 ] as they both undergo hydrophilic decomposition and are easily transported to the distal gut [ 17 ] for microbial fermentation [ 18 ]. Native konjac glucomannan has limited uses and has been chemically/physically/enzymatically modified to expand the range of functional properties, including biodegradable film, medical and pharmaceutical material, and encapsulation [ 17 , 19 ].…”