Effects of Bacillus subtilis on Epithelial Tight Junctions of Mice with Inflammatory Bowel Disease

In Vivo Study of the Efficacy of the Essential Oil of Zanthoxylum bungeanum Pericarp in Dextran Sulfate Sodium-Induced Murine Experimental Colitis

The purpose of this study was to investigate the protective effects and mechanisms of the essential oil of Zanthoxylum bungeanum pericarp (ZBEO) on dextran sulfate sodium (DSS)-induced experimental colitis in mice. ZBEO decreased DSS-induced body weight loss, the disease activity index, colon length shortening, colonic pathological damage, and myeloperoxidase activities. The production of pro-inflammatory mediators was significantly alleviated by ZBEO. Further mechanistic analysis showed that ZBEO inhibited inflammation by regulating NF-κB and PPARγ pathways. ZBEO also inhibited NLRP3 activation in colitis in mice. Furthermore, ZBEO contributed to the maintenance of tight junction architecture by regulating the expression of zonula occludens-1 during colitis. Surprisingly, treatment with ZBEO increased levels of the commensal bacteria containing Lactobacillus and Bifidobacteria but reduced Escherichia coli levels in the feces of mice. These results suggested that supplementation with ZBEO might provide a new dietary strategy for the prevention of ulcerative colitis.

The Anti-Inflammatory Effect and Intestinal Barrier Protection of HU210 Differentially Depend on TLR4 Signaling in Dextran Sulfate Sodium-Induced Murine Colitis

BACKGROUND

Ulcerative colitis (UC) is strongly associated with inflammation and intestinal barrier disorder. The nonselective cannabinoid receptor agonist HU210 has been shown to ameliorate inflamed colon in colitis, but its effects on intestinal barrier function and extraintestinal inflammation are unclear.

AIMS

To investigate the effects and the underlying mechanism of HU210 action on the UC in relation to a role of TLR4 and MAP kinase signaling.

METHODS

Wild-type (WT) and TLR4 knockout (Tlr4 ^-/-) mice were exposed to 4% dextran sulfate sodium (DSS) for 7 days. The effects of HU210 on inflammation and intestinal barrier were explored.

RESULTS

Upon DSS challenge, mice suffered from bloody stool, colon shortening, intestinal mucosa edema, pro-inflammatory cytokine increase and intestinal barrier destruction with goblet cell depletion, increased intestinal microflora accompanied with elevated plasma lipopolysaccharide, reduced mRNA expression of the intestinal tight junction proteins, and abnormal ratio of CD4⁺/CD8⁺ T cells in the intestinal Peyer's patches. Pro-inflammatory cytokines in the plasma and the lung, as well as pulmonary myeloperoxidase activity, indicators of extraintestinal inflammation were increased. Protein expression of p38α and pp38 was up-regulated in the colon of WT mice. Tlr4 ^-/- mice showed milder colitis. HU210 reversed the intestinal barrier changes in both strains of mice, but alleviated inflammation only in WT mice.

CONCLUSIONS

Our study indicates that in experimental colitis, HU210 displays a protective effect on the intestinal barrier function independently of the TLR4 signaling pathway; however, in the extraintestinal tissues, the anti-inflammatory action seems through affecting TLR4-mediated p38 mitogen-activated protein kinase pathway.

Ghrelin Attenuates Intestinal Barrier Dysfunction Following Intracerebral Hemorrhage in Mice

Intestinal barrier dysfunction remains a critical problem in patients with intracerebral hemorrhage (ICH) and is associated with poor prognosis. Ghrelin, a brain-gut peptide, has been shown to exert protection in animal models of gastrointestinal injury. However, the effect of ghrelin on intestinal barrier dysfunction post-ICH and its possible underlying mechanisms are still unknown. This study was designed to investigate whether ghrelin administration attenuates intestinal barrier dysfunction in experimental ICH using an intrastriatal autologous blood infusion mouse model. Our data showed that treatment with ghrelin markedly attenuated intestinal mucosal injury at both histomorphometric and ultrastructural levels post-ICH. Ghrelin reduced ICH-induced intestinal permeability according to fluorescein isothiocyanate conjugated-dextran (FITC-D) and Evans blue extravasation assays. Concomitantly, the intestinal tight junction-related protein markers, Zonula occludens-1 (ZO-1) and claudin-5 were upregulated by ghrelin post-ICH. Additionally, ghrelin reduced intestinal intercellular adhesion molecule-1 (ICAM-1) expression at the mRNA and protein levels following ICH. Furthermore, ghrelin suppressed the translocation of intestinal endotoxin post-ICH. These changes were accompanied by improved survival rates and an attenuation of body weight loss post-ICH. In conclusion, our results suggest that ghrelin reduced intestinal barrier dysfunction, thereby reducing mortality and weight loss, indicating that ghrelin is a potential therapeutic agent in ICH-induced intestinal barrier dysfunction therapy.