Extracts from Hericium erinaceus relieve inflammatory bowel disease by regulating immunity and gut microbiota

Abstract

Hericium erinaceus (HE), a traditional edible mushroom, is known as a medicine food homology to ameliorate gastrointestinal diseases. To investigate whether HE is clinically effective in alleviating inflammatory bowel disease (IBD), HE extracts (polysaccharide, alcoholic extracts and whole extracts were prepared using solvent extraction methods) were administrated for 2 weeks in rats with IBD induced by trinitro-benzene-sulfonic acid (TNBS) enema (150 mg/kg). Significant clinical and histological changes in IBD rats were identified, including damage activity, common morphous and tissue damage index scores in colonic mucosa and myeloperoxidase (MPO) activity. The damage activity, common morphous and tissue damage index scores in colonic mucosa (P <0.05) were improved, MPO activities were decreased. Inflammatory factors were also differentially expressed in colonic mucosa in IBD rats, including serum cytokines, Foxp3 and interleukin (IL)-10 were increased while NF-κB p65 and tumor necrosis factor (TNF)-α were decreased (P <0.05), and T cells were activated (P <0.05), especially in the alcohol extracts-treated group. We also found that the structure of gut microbiota of the H. erinaceus extracts-treated groups changed significantly by compared with the model group. Further studies revealed that the polysaccharides in HE extracts may play a prebiotic role, whereas the alcoholic extracts show bactericidin-like and immunomodulatory effects. Taken together, we demonstrated that H. erinaceus extracts could promote the growth of beneficial gut bacteria and improve the host immunity in vivo IBD model, which shows clinical potential in relieving IBD by regulating gut microbiota and immune system.

Keywords: Hericium erinaceus; anti-inflammatory; gut microbiota; immune-enhancing effect; inflammatory bowel disease.

Figure 1. DAI scores and histopathological changes in the colon of rats in differently treated groups after induction by TNBS

DAI scores were calculated according to the (A) weight loss, stool consistency, and blood in feces, length of the colon, weight of the colon, and the colon index (weight/length), with six rats per group; (B) histopathological changes in the colon. Normal, group without any treatment; model, the TNBS-induced group; WE, the whole extract-treated group after TNBS induction; PE, the polysaccharides extract-treated group after TNBS induction; AE, the alcohol extracts-treated group after TNBS induction. Values are expressed as means ± standard deviation. ^#P < 0.05 vs the control group, *P < 0.05, **P < 0.01 vs the model group, indicating significant differences compared with the model group.

Figure 2. Effects of H. erinaceus extracts on TNBS-induced rats

Rats in the normal and model groups were induced by TNBS; WE, the whole extract-treated group after TNBS induction; PE, the polysaccharides extract-treated group after TNBS induction; AE, the alcohol extract-treated group after TNBS induction. The positive control group was treated with 100 mg/(kg·day) of 5-aminosalicylic acid. After treatment for 14 days, the cytokines IL-1α (A), IL-2 (B), IL-8 (C), IL-10 (D), IL-11 (E), IL-12 (F), TNF-α (G), TNF-γ (H), VGEF (I), M-CSF (J), MIP-α (K) and MPO (L) were produced. The assays were carried out according to the procedures recommended in the enzyme-linked immunosorbent assay kit manual. Values were means ± standard deviation of three independent experiments. ^#P < 0.05 vs the normal group, *P < 0.05, **P < 0.01 vs the TNBS-treated group, indicating significant differences compared with the LPS-treated group.

Figure 3. Immunohistochemistry staining of Foxp3, NF-κB p65, TNF-α, and IL-10 in the colons of different experimental groups (×200) in IBD rats

Rats in the normal without nothing treatment, and model groups were induced by TNBS; WE, the whole extract-treated group after TNBS induction; PE, the polysaccharides extract-treated group after TNBS induction; AE, the alcohol extract-treated group after TNBS induction.

Figure 4. The Bray coefficient of cluster analysis and stacked figure of family composition based on the best classification level of the IBD rats induced by TNBS enema

Figure 5. Tree species classification of the differently treated samples from IBD rats induced by TNBS enema

The pie chart of different colors represents different samples in that classification unit. The size of the radius denotes the tag number accounts for the proportion of the total tag; the larger the radius, the higher the abundance. The numbers next to the pie chart represent the percentage of tag number of the percentage of the total tag.

Figure 6. Tags with significant differences in the relative abundance of different grouping distribution of genus in IBD rats induced by TNBS enema

Figure 7. Polysaccharides extracted from H. erinaceus improved the pathological parameters of the TNBS-induced mice

(A) Body weight changes; (B) levels of LPS in serum; (C) levels of cytokines GM-CSF, TNF-γ, IL-10, IL-12, IL-17α, IL-4, TNF-α, and VGEF-α in serum; (D) histopathological changes in the colon; and (E) histopathological changes in the spleen. Control is the normal without any treatments; model (Mice were induced by TNB), model and high-dose antibiotics, polysaccharides [100 mg/(kg · d)], Bifidobacterium, polysaccharides plus high-dose antibiotics, polysaccharides plus Bifidobacterium, Bifidobacterium plus high-dose antibiotics, and polysaccharides plus Bifidobacterium plus high-dose antibiotics.

Figure 8

Immunohistochemistry staining of (A) TNF-α, (B) NF-κB p65, (C) IL-17, (D) Foxp3 and the mean optical density values were used for analyzing the results of immunohistochemistry (E) in the colons of different experimental groups in IBD mice induced by TNBS enema after treatment with polysaccharides extracted from H. erinaceus.

Figure 9

Polysaccharides extracted from H. erinaceus showed a good prebiotic effect on TNBS-induced mice.

Figure 10

Effect of AE on the TNF-α- and LPS-induced Caco-2 cells (A), CD⁴⁺CD²⁵⁺Treg cells in TNBS-induced IBD rats induced by TNBS enema (B), relative abundance of B. friagilis differently treated IBD rats (C), and the relative content of fatty acids in AE from H. erinaceus analysis by GC–MS (D).

Figure 11

Active ingredients and mode of action of H. erinaceus for IBD prevention and treatment.