Morchella importuna Flavones Improve Intestinal Integrity in Dextran Sulfate Sodium-Challenged Mice.

Yingyin Xu,Zhiyuan Zhang,Ying Chen,Bingcheng Gan,Weihong Peng,Xiaolan He,Jie Zhou,Liyuan Xie,Jie Tang

doi:10.3389/fmicb.2021.742033

Abstract

Morchella importuna, as an edible fungus, has various health benefits. However, the effects of M. importuna on intestinal health are rarely investigated. Hence, this study aims to ascertain the influences of flavones from the fruiting bodies of M. importuna (hereinafter abbreviated as MIF) on dextran sulfate sodium (DSS)-induced damage to intestinal epithelial barrier in C57BL/6J mice. In this (14-day) study, 144 C57BL/6J mice were divided into four groups: (1) Control; (2) DSS treatment; (3) DSS treatment + 100 mg/kg MIF (LMIF); (4) DSS treatment + 200 mg/kg MIF (HMIF). On days 8-14, mice in the challenged groups were challenged with 3.5% DSS, while the control group received an equal volume of normal saline. Then, serum and intestinal samples were obtained from all mice. The results showed that MIF ingestion enhanced intestinal integrity in DSS-challenged mice, as evinced by the elevated (p < 0.05) abundances of occludin, claudin-1, and zonula occludens-1 proteins. Meanwhile, MIF ingestion reduced (p < 0.05) the colonic interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), and interferon-γ (IFN-γ) concentrations and increased the superoxide dismutase and catalase activities and Shannon and Simpson indices in DSS-challenged mice. Moreover, MIF ingestion reduced (p < 0.05) the abundance of phospho-nuclear factor (NF)-κB and increased the abundance of phospho-Nrf2 in DSS-challenged mice. Taken together, MIF protects against intestinal barrier injury in C57BL/6J mice via a mechanism that involves inhibiting NF-κB activation and promoting Nrf2 activation, as well as regulating intestinal microbiota.

Highlights

The intestinal epithelial barrier is a single layer of cells lining the gut that comprises the apical cell membrane and intercellular tight junctions of intestinal epithelial cells (Ulluwishewa et al, 2011; Peterson and Artis, 2014)
Crypt depth, and villus height to crypt depth (VCR) serve as criteria that reflect gross intestinal morphology (Liu et al, 2008; Qin et al, 2018)
MIF supplementation increased colonic villus height and VCR, which implies that MIF improved intestinal structure

Summary

Introduction

The intestinal epithelial barrier is a single layer of cells lining the gut that comprises the apical cell membrane and intercellular tight junctions of intestinal epithelial cells (Ulluwishewa et al, 2011; Peterson and Artis, 2014). It acts as a selective barrier that allows the absorption of nutrient substances while inhibiting the translocation of luminal pathogens Dietary bioactive substances have been found to improve intestinal barrier function by strengthening the intestinal barrier, attenuating the inflammatory responses and modulating microbiota composition (Yang et al, 2012; Tian et al, 2019; Wan et al, 2020). Some bioactive compounds have been found in the Morchella mushroom fruiting body, such as polysaccharides, ergosterol derivatives, microthecin, and so on (Wang et al, 2019). To the best of our knowledge, the ameliorative effects of Morchella mushrooms on intestinal barrier function have not been investigated and warrant exploration

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