Effects of Dietary Oat Beta-Glucans on Colon Apoptosis and Autophagy through TLRs and Dectin-1 Signaling Pathways-Crohn's Disease Model Study.

ABSTRACT:

Background

Crohn's disease (CD) is characterized by chronic inflammation of the gastrointestinal tract with alternating periods of exacerbation and remission. The aim of this study was to determine the time-dependent effects of dietary oat beta-glucans on colon apoptosis and autophagy in the CD rat model.

Methods

A total of 150 Sprague-Dawley rats were divided into two main groups: healthy control (H) and a TNBS (2,4,6-trinitrobenzosulfonic acid)-induced colitis (C) group, both including subgroups fed with feed without beta-glucans (?G-) or feed supplemented with low- (?Gl) or high-molar-mass oat beta-glucans (?Gh) for 3, 7, or 21 days. The expression of autophagy (LC3B) and apoptosis (Caspase-3) markers, as well as Toll-like (TLRs) and Dectin-1 receptors, in the colon epithelial cells, was determined using immunohistochemistry and Western blot.

Results

The results showed that in rats with colitis, after 3 days of induction of inflammation, the expression of Caspase-3 and LC3B in intestinal epithelial cells did not change, while that of TLR 4 and Dectin-1 decreased. Beta-glucan supplementation caused an increase in the expression of TLR 5 and Dectin-1 with no changes in the expression of Caspase-3 and LC3B. After 7 days, a high expression of Caspase-3 was observed in the colitis-induced animals without any changes in the expression of LC3B and TLRs, and simultaneously, a decrease in Dectin-1 expression was observed. The consumption of feed with ?Gl or ?Gh resulted in a decrease in Caspase-3 expression and an increase in TLR 5 expression in the C?Gl group, with no change in the expression of LC3B and TLR 4. After 21 days, the expression of Caspase-3 and TLRs was not changed by colitis, while that of LC3B and Dectin-1 was decreased. Feed supplementation with ?Gh resulted in an increase in the expression of both Caspase-3 and LC3B, while the consumption of feed with ?Gh and ?Gl increased Dectin-1 expression. However, regardless of the type of nutritional intervention, the expression of TLRs did not change after 21 days.

Conclusions

Dietary intake of ?Gl and ?Gh significantly reduced colitis by time-dependent modification of autophagy and apoptosis, with ?GI exhibiting a stronger effect on apoptosis and ?Gh on autophagy. The mechanism of this action may be based on the activation of TLRs and Dectin-1 receptor and depends on the period of exacerbation or remission of CD.

SUBMITTER: Kopiasz L 

PROVIDER: S-EPMC7911679 | biostudies-literature | 2021 Jan

REPOSITORIES: biostudies-literature