Lycium barbarum polysaccharide remodels colon inflammatory microenvironment and improves gut health.

Aim: Disturbed intestinal microbiota has been implicated in the inflammatory microenvironment of the colon, which usually results in ulcerative colitis (UC). Given the limitations of these drugs, it is important to explore alternative means of protecting the gut health from UC. This study aimed to investigate the potential of polysaccharides as beneficial nutrients in the regulation of the gut microbiota, which determines the inflammatory microenvironment of the colon. Materials and methods: Mice were treated with dextran sulfate sodium (DSS) to evaluate the effects and mechanisms of Lycium barbarum polysaccharide (LBP) in remodeling the inflammatory microenvironment and improving gut health. Body weight and disease activity indices were monitored daily. Hematoxylin and eosin staining was used to analyze colon dynamics. The levels of inflammatory indicators and expression of MUC-2, claudin-1, ZO-1, and G-protein-coupled receptor 5 (TGR5) were determined using assay kits and immunohistochemistry, respectively. 16S rRNA high-throughput sequencing of the intestinal microbiota and liquid chromatography-tandem mass spectrometry for related bile acids were used. Results: LBP significantly improved the colonic tissue structure by upregulating MUC-2, claudin-1, and ZO-1 protein expression. The bacterial genus Dubosiella was dominant in healthy mice, but significantly decreased in mice treated with DSS. LBP rehabilitated Dubosiella in the sick guts of DSS mice to a level close to that of healthy mice. The levels of other beneficial bacterial genera Akkermansia and Bifidobacterium were also increased, whereas those of the harmful bacterial genera Turicibacter, Clostridium_sensu_stricto_1, Escherichia-Shigella, and Faecalibaculum decreased. The activity of beneficial bacteria promoted the bile acids lithocholic and deoxycholic acids in mice with UC, which improved the gut barrier function through the upregulation of TGR5. Conclusion: The inflammatory microenvironment in the gut is determined by the balance of the gut microbiota. LBP showed great potential as a beneficial nutrient for rehabilitating Dubosiella which is dominant in the gut of healthy mice. Nutrient-related LBP may play an important role in gut health management.

Chitosan nanocomposite films based on halloysite nanotubes modification for potential biomedical applications.

Chitosan is attracting increasing attention for biomedical applications because of its biocompatibility. In the present study, raw halloysite nanotubes (RHNTs) were functionalised with (3-aminopropyl) triethoxysilane (APTS) and then a sequence of novel chitosan biofilms were prepared by adding amino-modified halloysite nanotubes (HNTs-NH2) as a reinforcing material and ethylene glycol diglycidyl ether (EGDE) as a cross-linking agent. The reaction between the APTS and the RHNTs was demonstrated through characterisation of the HNTs-NH2. Fourier transform infra-red spectroscopy (FTIR) and X-ray diffraction (XRD) results confirmed the interaction of HNTs-NH2 with chitosan and EGDE. Scanning electron microscopy (SEM) showed a transformation of the surface morphology of the chitosan films. Measurement of the mechanical and thermal properties showed that the nanocomposite films exhibited substantial improvements in tensile strength, elongation at break and thermal stability compared with those of the pure chitosan films. However, the swelling rate of the nanocomposite films decreased upon incorporation of the HNTs-NH2 and EGDE. In addition, the water vapour transmission rate (WVTR) of the nanocomposite films was also improved. Given the aforementioned results, chitosan nanocomposites are promising biomedical materials.