Colonic Tissue Injury Research Articles

Artemisia argyi polyphenols Attenuates DSS-induced colitis in mice by regulating the structural composition of gut microbiota

BackgroundIntestinal health is affected by heredity, lifestyle, and structure of gut microbiota. The imbalance of symbiotic and harmful bacteria in gut microbiota may increase the occurrence of colonic inflammation. Supplementary A. muciniphila can improve the survival rate of colitis mice, reduce colon tissue injury, and the expression of anti-inflammatory factors was upregulated. Artemisia argyi has been reported to have anti-inflammatory, antioxidant, bactericidal, and immunomodulatory effects. However, its anti-inflammatory effect and mechanism, and its influence on gut microbiota and metabolites are still unclear yet. PurposeTo explore whether Artemisia argyi Polyphenols(AAPs) can alleviate ulcerative colitis (UC) by changing gut microbiota. MethodsThe therapeutic effect of AAPs on colitis was investigated by inducing ulcerative colitis in mice using dextran sodium sulfate (DSS) and administering different doses of AAPs orally to mice. Exploring the levels of inflammatory proteins, oxidative stress proteins, and barrier proteins using western blotting and immunofluorescence, and explored the structural changes of gut microbiota and its metabolites. Meanwhile, in order to explore whether the role of AAPs in alleviating colitis is based on the regulation of gut microbiota structure, we conducted fecal microbiota transplantation (FMT). ResultsIt showed that AAPs and FMT trial alleviated DSS-induced colonic injury, including clinical parameters and pathological injury of colon tissue, reduction in the expression of inflammatory proteins: IL-6, TNF-α, p-p65, p-IκBα, and increase in the expression of antioxidant proteins: Nrf2, NQO-1 and HO-1 and barrier proteins: Claudin-1, Occludin, ZO-1 and MUC2. AAPs and FMT promoted the content of beneficial bacteria, such as Butyricimonas and Lactobacillus, and the content of beneficial metabolites for instance acetic acid, butyric acid, and valeric acid has also increased. ConclusionThese results suggested that AAPs might improve DSS-induced colonic injury by changing the structural of gut microbiota while promoting the synthesis of fatty acids in the intestine, thereby providing a theoretical basis for using AAPs to treat ulcerative colitis.

Banxia Xiexin decoction combined with 5-ASA protects against CPT-11-induced intestinal dysfunction in rats via inhibiting TLR4/NF-κB signaling pathway.

Banxia Xiexin decoction (BXD) can control irinotecan (CPT-11)-caused delayed diarrhea, but the corresponding mechanism remains undefined. This paper aimed to uncover the mechanism of BXD in regulating CPT-11-caused delayed diarrhea. Sprague-Dawley (SD) rats were assigned into the control, model, BXD low-dose (BXD-L, 5 g/kg), BXD medium-dose (BXD-M, 10 g/kg), BXD high-dose (BXD-H, 15 g/kg), 5-aminosalicylic acid (5-ASA, 10 mL/kg), and BXD-M + 5-ASA groups. Rats were injected intraperitoneally with 150 mg/kg CPT-11 at Day 4 and Day 5 to induce delayed diarrhea, and later treated with various doses (low, medium, and high) of BXD and 5-ASA for 9 days, except for rats in control group. The body weight of rats was measured. The rat colon tissue injury, inflammatory cytokine levels, and the activation of toll-like receptor 4/nuclear factor-κB (TLR4/NF-κB) signaling pathway were detected. BXD (5, 10, or 15 g/kg) or 5-ASA (10 mL/kg) alleviated body weight loss and colon tissue injury, decreased levels of inflammatory cytokines, and inactivated TLR4/NF-κB signaling pathway in CPT-11-induced model rats. BXD at 10 g/kg (the optimal concentration) could better treat CPT-11-induced intestinal dysfunction, as evidenced by the resulting approximately 50% reduction on injury score of model rats. Moreover, BXD-M (10 g/kg) synergistic with 5-ASA (10 mL/kg) further strengthened the inhibition on rat body weight loss, colon tissue injury, inflammatory cytokine levels, and TLR4/NF-κB signaling pathway. To sum up, BXD has a protective effect against CPT-11-induced intestinal dysfunction by inhibiting inflammation through inactivation TLR4/NF-κB signaling pathway. In particular, the combined use of BXD and 5-ASA holds great promise for treating CPT-11-induced delayed diarrhea.

Qingzhuan dark tea polysaccharides-zinc alleviates dextran sodium sulfate-induced ulcerative colitis.

Qingzhuan dark tea polysaccharides (QDTP) have been complexed with Zinc (Zn) to form the Qingzhuan dark tea polysaccharides-Zinc (QDTP-Zn) complex. The present study investigated the protective effects of QDTP-Zn on ulcerative colitis (UC) in mice. The UC mouse model was induced using dextran sodium sulfate (DSS), followed by oral administration of QDTP-Zn (0.2 and 0.4 g kg-1 day-1). QDTP-Zn demonstrated alleviation of UC symptoms in mice, as evidenced by a decrease in disease activity index scores. QDTP-Zn also regulated colon tissue injury by upregulating ZO-1 and occludin protein expression, at the same time as downregulating tumor necrosis factor-α and interleukin-6β levels. Furthermore, QDTP-Zn induced significant alterations in the abundance of bacteroidetes and firmicutes and notably increased levels of short-chain fatty acids (SCFAs), particularly acetic acid, propionic acid, and butyric acid. In summary, QDTP-Zn exhibits therapeutic potential in alleviating enteritis by fortifying the colonic mucosal barrier, mitigating inflammation and modulating intestinal microbiota and SCFAs levels. Thus, QDTP-Zn holds promise as a functional food for both the prevention and treatment of UC. © 2024 Society of Chemical Industry.

Network pharmacology mechanisms and experimental verification of licorice in the treatment of ulcerative colitis

Ethnopharmacological relevanceLicorice is widely used in the treatment of ulcerative colitis (UC) and has good antioxidant and anti-inflammatory effects, but its specific active ingredients and mechanisms of action are still unknown. The purpose of the studyTo elucidate the specific molecular mechanisms of licorice in the treatment of UC and to experimentally verify its activity. MethodsThrough network pharmacology, the active ingredients of licorice and the molecular targets of UC were identified. A traditional Chinese medicine (TCM)-components-target-disease network diagram was established, and the binding energies of the active ingredient and targets of licorice were verified by molecular docking. A BALB/c mice model of UC was established by treatment with 3% dextran sulfate sodium (DSS). The effect of licorice on colon tissue injury was histologically assessed. The expression of IL-6 and IL-17 in colon tissue was detected by immunohistochemistry (IHC). Transmission electron microscopy (TEM) was used to observe morphological changes in mitochondria in the colon. Caco2 cells were treated with lipopolysaccharide (LPS) for 24 h to establish the cell inflammatory damage model, and cells were exposed to different concentrations of drug-containing serum of Licorice (DCSL) for 24 h. In cells treated with the drug, the contents of oxidation markers were measured and ELISA was used to determine the levels of inflammatory factors in the cells. TEM was used to observe morphological changes in mitochondria. ZO-1 and occludin were detected by Western blotting. DCSL effects on autophagy were evaluated by treating cells with DCSL and autophagy inhibitor for 24 h after LPS injection. Small interfering ribonucleic acid (si-RNA) was used to silence Nrf2 gene expression in Caco2 cells to observe the effects of DCSL on autophagy through the Nrf2/PINK1 pathway. Nrf2, PINK1, HO-1, Parkin, P62, and LC3 were detected by Western blotting. ResultsNinety-one active ingredients and 339 action targets and 792 UC disease targets were identified, 99 of which were overlapping targets. Molecular docking was used to analyze the binding energies of liquiritin, liquiritigenin, glycyrrhizic acid, and glycyrrhetinic acid to the targets, with glycyrrhetinic acid having the strongest binding energy. In the UC mouse model, licorice improved colon histopathological changes, reduced levels of IL-6 and IL-17 and repaired mitochondrial damage. In the LPS-induced inflammation model of Caco2 cells, DCSL decreased MDA, IL-1β, Il-6, and TNF-α levels and increased those of Superoxide Dismutase (SOD), glutathione peroxidase (GSH-PX), and IL-10, and improved the morphological changes of mitochondria. Increased expression of Nrf2, PINK1, Parkin, HO-1, ZO-1, occludin, P62, and LC3 promoted autophagy and reduced inflammation levels. ConclusionLicorice improves UC, which may be related to the activation of the Nrf2/PINK1 signaling pathway that regulates autophagy.

Effect of Extracelluar Vesicles Derived from Akkermansia muciniphila on Intestinal Barrier in Colitis Mice.

Inflammatory bowel disease (IBD) is a chronic and recurrent disease. It has been observed that the incidence and prevalence of IBD are increasing, which consequently raises the risk of developing colon cancer. Recently, the regulation of the intestinal barrier by probiotics has become an effective treatment for colitis. Akkermansia muciniphila-derived extracellular vesicles (Akk EVs) are nano-vesicles that contain multiple bioactive macromolecules with the potential to modulate the intestinal barrier. In this study, we used ultrafiltration in conjunction with high-speed centrifugation to extract Akk EVs. A lipopolysaccharide (LPS)-induced RAW264.7 cell model was established to assess the anti-inflammatory effects of Akk EVs. It was found that Akk EVs were able to be absorbed by RAW264.7 cells and significantly reduce the expression of nitric oxide (NO), TNF-α, and IL-1β (p < 0.05). We explored the preventative effects on colitis and the regulating effects on the intestinal barrier using a mouse colitis model caused by dextran sulfate sodium (DSS). The findings demonstrated that Akk EVs effectively prevented colitis symptoms and reduced colonic tissue injury. Additionally, Akk EVs significantly enhanced the effectiveness of the intestinal barrier by elevating the expression of MUC2 (0.53 ± 0.07), improving mucus integrity, and reducing intestinal permeability (p < 0.05). Moreover, Akk EVs increased the proportion of the beneficial bacteria Firmicutes (33.01 ± 0.09%) and downregulated the proportion of the harmful bacteria Proteobacteria (0.32 ± 0.27%). These findings suggest that Akk EVs possess the ability to regulate immune responses, protect intestinal barriers, and modulate the gut microbiota. The research presents a potential intervention approach for Akk EVs to prevent colitis.

Fufangxiaopi formula alleviates DSS-induced colitis in mice by inhibiting inflammatory reaction, protecting intestinal barrier and regulating intestinal microecology

Ethnopharmacological relevanceFufangxiaopi Formula (FF) is a modified form of Sishen Wan, traditionally used for treating diarrhea. The application of FF for treating ulcerative colitis (UC) has achieved desirable outcomes in clinical settings. However, the underlying mechanism of the effect of FF on UC is yet to be determined. Aim of studyThis study aimed to evaluate the protective effect and underlying mechanism of FF on mice with dextran sodium sulfate (DSS)-induced colitis. Materials and methodsIn vivo, the efficacy of FF on the symptoms associated with DSS-induced colitis in mice was clarified by observing the body weight change, colon length, DAI score, and H&E staining. The release of inflammatory mediators in mouse colon tissues was detected by ELISA and MPO, and the contents of TLR4/NF-κB signaling pathway and MAPK signaling pathway-related proteins, as well as intestinal barrier-related proteins, were detected in mouse colon tissues by western blot method. Changes in the content of barrier proteins in mouse colon tissues were detected by immunofluorescence. 16S rRNA sequencing and FMT were performed to clarify the effects of FF on intestinal flora. In vitro, the effect of FF-containing serum on LPS-induced inflammatory mediator release from RAW264.7 cells were detected by qRT-PCR. The contents of TLR4/NF The effects of FF-containing serum on B signaling pathway and MAPK signaling pathway related proteins in RAW264.7 cells and intestinal barrier related proteins in Caco-2 cells were detected by western blot. The effects of FF-containing serum on LPS-induced nuclear translocation of p65 protein in RAW264.7 cells and barrier-associated protein in Caco-2 cells were detected by immunofluorescence. ResultsIn vivo studies showed that FF could significantly alleviate the symptoms of UC, including reducing colon length, weight loss, clinical score, and colon tissue injury in mice. FF could significantly reduce the secretion of proinflammatory cytokines by suppressing the activation of the TLR4/NF-κB and MAPK signaling pathways. Moreover, FF could protect the integrity of intestinal barriers by significantly increasing claudin-3, occludin, and ZO-1 expression levels. 16S rRNA sequencing and FMT elucidate that FF can alleviate symptoms associated with colitis in mice by interfering with intestinal flora. In vitro studies showed that FF drug-containing serum could significantly inhibit proinflammatory responses and attenuate the secretion of iNOS, IL-1β, TNF-α, IL-6, and COX-2 by suppressing the activation of TLR4/NF-κB and MAPK signaling pathways in RAW264.7 cells. Furthermore, FF could protect the Caco-2 cell epithelial barrier. ConclusionFF could alleviate DSS-induced colitis in mice by maintaining the intestinal barrier, inhibiting the activation of TLR4/NF-κB and MAPK signaling pathways, reducing the release of proinflammatory factors, and regulating intestinal microecology.

Chronic exposure to low-dose deltamethrin can lead to colon tissue injury through PRDX1 inactivation-induced mitochondrial oxidative stress injury and gut microbial dysbiosis

ObjectiveTo date, it is unclear whether deltamethrin (DLM) intake causes damage to colon tissue. Hence, in this study, we aimed to clarify the effect of long-term exposure to low-dose DLM on colon tissues, and its potential mechanisms. MethodsMice were treated with DLM (0.2 mg/kg/day) or DLM combined with N-acetyl-l-cysteine (NAC) (50 mg/kg/day) for 8 weeks. Human colon cancer cells (HCT-116) were treated with DLM (0, 25, 50, or 100 µM), NAC (2 mM), or overexpression plasmids targeting peroxiredoxin 1 (PRDX1) for 48 h. DLM was detected using a DLM rapid detection card. Colon injury was evaluated using haematoxylin and eosin staining and transmission electron microscopy. Apoptosis was determined using immunofluorescence staining (IF), western blotting (WB) and flow cytometry (FC) assays. MitoTracker, JC-1, and glutathione (GSH) detection were used to detect mitochondrial oxidative stress. Intestinal flora were identified by 16 S rDNA sequencing. ResultsDLM accumulation was detected in the colon tissue and faeces of mice following long-term intragastric administration. Interestingly, our results showed that, even at a low dose, long-term intake of DLM resulted in severe weight loss and decreased the disease activity index scores and colon length. The results of IF, WB, and FC showed that DLM induced apoptosis in the colon tissue and cells. MitoTracker, JC-1, and GSH assays showed that DLM increased mitochondrial stress in colonic epithelial cells. Mechanistic studies have shown that increased mitochondrial stress and apoptosis are mediated by PRDX1 inhibition. Further experiments showed that PRDX1 overexpression significantly reduced DLM-induced oxidative stress injury and apoptosis. In addition, we observed that chronic exposure to DLM altered the composition of the intestinal flora in mice, including an increase in Odoribacter and Bacteroides and a decrease in Lactobacillus. The gut microbial richness decreased after DLM exposure in mice. Supplementation with NAC both in vivo and in vitro alleviated DLM-induced oxidative stress injury, colonic epithelial cell apoptosis, and gut microbial dysbiosis. ConclusionChronic exposure to DLM, even at small doses, can cause damage to the colon tissue, which cannot be ignored. The production and use of pesticides such as DLM should be strictly regulated during agricultural production.

Luteolin alleviates ulcerative colitis in rats via regulating immune response, oxidative stress, and metabolic profiling.

Ulcerative colitis (UC) is an inflammatory bowel disease and associated with metabolic imbalance. Luteolin (LUT) reportedly exhibits anti-inflammatory activity. However, its regulatory effects on metabolites remain indistinct. Here, the effects of LUT on immune response and oxidative stress in UC were determined. Serum metabolomics profiles of UC rats treated with LUT were obtained utilizing liquid chromatography-mass spectrometry. The results revealed that LUT treatment alleviated colon tissue injury, colon shortening, weight loss, and inflammatory response in UC rats. Additionally, the levels of superoxide dismutase and total antioxidant capacity were elevated, but malondialdehyde content was reduced in serum of UC rats, while these changes were abrogated by LUT. Metabolomics analysis unveiled that l-malic acid, creatinine, l-glutamine, and l-lactic acid levels were remarkably decreased, while dimethyl sulfone, 5-methylcytosine, cysteine-S-sulfate, and jasmonic acid levels were notably increased after LUT treatment. Furthermore, differential metabolites primarily participated in d-glutamine and d-glutamate metabolism, glutathione metabolism, and citrate cycle pathways. In summary, these results demonstrated that LUT improved immune response, alleviated oxidative stress, and altered metabolites in UC rats. This study lays the root for further exploring the mechanism of LUT in the treatment of UC.

Panax quinquefolius polysaccharides ameliorate ulcerative colitis in mice induced by dextran sulfate sodium.

This study aimed to investigate the ameliorative effect of the polysaccharides of Panax quinquefolius (WQP) on ulcerative colitis (UC) induced by dextran sulfate sodium (DSS) in mice and to explore its mechanism. Male C57BL/6J mice were randomly divided into the control group (C), model group (DSS), positivecontrol mesalazine (100 mg/kg, Y) group, and low (50 mg/kg, L), medium (100 mg/kg, M) and high dose (200 mg/kg, H) of WQP groups. The UC model was induced by free drinking water with 2.5% DSS for 7 days. During the experiment, the general condition of the mice was observed, and the disease activity index (DAI) was scored. The conventional HE staining was used to observe pathological changes in mice's colon, and the ELISA method was used to detect the levels of interleukin-6 (IL-6), IL-4, IL-8, IL-10, IL-1β and tumor necrosis factor-α (TNF-α) in mice's colon. The changes in gut microbiota in mice were detected by high-throughput sequencing; the concentration of short-chain fatty acids (SCFAs) was determined by gas chromatography; the expression of related proteins was detected by Western blot. Compared with the DSS group, the WQP group showed a significantly lower DAI score of mice and an alleviated colon tissue injury. In the middle- and high-dose polysaccharides groups, the levels of pro-inflammatory cytokines IL-6, IL-8, IL-1β and TNF-α in the colonic tissue were significantly decreased (P<0.05), while the levels of IL-4 and IL-10 were significantly increased (P<0.05). The 16S rRNA gene sequencing results showed that different doses of WQP could regulate the composition and diversity of gut microbiota and improve its structure. Specifically, at the phylum level, group H showed an increased relative abundance of Bacteroidetes and a decreased relative abundance of Firmicutes compared with the DSS group, which was closer to the case in group C. At the family level, the relative abundance of Rikenellaceae in L, M and H groups increased significantly, close to that in group C. At the genus level, the relative abundance of Bacteroides, Shigella and Oscillospira in the H group increased significantly, while that of Lactobacillus and Prevotella decreased significantly. The high-dose WQP group could significantly increase the contents of acetic acid, propionic acid, butyric acid, and total SCFAs. Different doses of WQP also increased the expression levels of tight junction proteins ZO-1, Occludin and Claudin-1. To sum up, WQP can regulate the gut microbiota structure of UC mice, accelerate the recovery of gut microbiota, and increase the content of Faecal SCFAs and the expression level of tight junction proteins in UC mice. This study can provide new ideas for the treatment and prevention of UC and theoretical references for the application of WQP.

Therapeutic effect of Yiyi Fuzi Baijiang formula on TNBS-induced ulcerative colitis via metabolism and Th17/Treg cell balance.

Yiyi Fuzi Baijiang formula (YFB) is a traditional Chinese medicine prescription composed of Coix seed, Radix Aconiti Lateralis and Patrinia villosa, which has been used to treat ulcerative colitis (UC) for thousands of years. To investigate the therapeutic effect and metabolic analysis of YFB formula on UC in rats induced by 2,4,6-trinitro-benzene sulfonic acid (TNBS). Six main alkaloids in the YFB formula were determined by UPLC‒MS/MS. The rat UC model was induced by TNBS, and the therapeutic effect of YFB formula on UC was evaluated by disease activity index (DAI) score and hematoxylin-eosin (HE) staining. UPLC-QTRAP-MS metabolomics technology was used to screen potential biomarkers for YFB treatment of UC in combination with multivariate data statistics and further analyze related metabolic pathways. Western blotting was used to detect the protein levels of NLRP1, NLRP3, NLRC4, ASC, pro-caspase1 and Caspase-1 in rat liver tissues. ELISA and immunohistochemistry were used to detect the contents of interleukin (IL)-17A, IL-21, IL-22, IL-6, TNF-α, IL-1β and IL-18 in rat serum and liver tissues. The DAI scores of the YFB groups were significantly reduced, and colon tissue injury was significantly improved (p<0.01). The results of metabolomics analysis revealed 29 potential biomarkers in serum and 27 potential biomarkers in liver. YFB formula can treat UC by affecting glycerophospholipid metabolism, primary bile acid biosynthesis, glyoxylic acid and dicarboxylic acid metabolism, and arginine and proline metabolism. Compared with the model group, the contents of IL-17A, IL-21, IL-22, IL-6, TNF-α, IL-1β and IL-18 in the YFB groups were decreased in a dose-dependent manner (p<0.01). Compared with those in the model group, the protein levels of NLRP1, NLRP3, NLRC4, ASC, pro-caspase1 and Caspase-1 in the YFB groups were significantly decreased in a dose-dependent manner (p<0.01). The therapeutic effect of YFB formula on UC rats was dose dependent, and the effect of the YFB (2.046g/kg) group was close to that of the positive group. YFB formula has an anti-inflammatory effect on UC by regulating the balance of Th17/Treg cells in rats.

Sinisan ameliorates colonic injury induced by water immersion restraint stress by enhancing intestinal barrier function and the gut microbiota structure

Context Sinisan (SNS) has been used to treat psychosomatic diseases of the digestive system. But little is known about how SNS affects water immersion restraint stress (WIRS). Objective To study the effects of SNS on colonic tissue injury in the WIRS model. Materials and methods Forty-eight Kunming (KM) mice were randomized into 6 groups (n = 8): The control and WIRS groups receiving deionized water; the SNS low-dose (SL, 3.12 g/kg/d), SNS middle-dose (SM, 6.24 g/kg/d), SNS high-dose (SH, 12.48 g/kg/d), and diazepam (DZ, 5 mg/kg/d) groups; each with two daily administrations for 5 consecutive days. The 5 treatment groups were subjected to WIRS for 24 h on day 6. The effects of SNS on colon tissue injury caused by WIRS were assessed by changes in colon histology, inflammatory cytokines, brain-gut peptides, and tight junction (TJ) proteins levels. 16S rRNA gene sequencing was used to detect the regulation of the gut microbiota. Results SNS pretreatment significantly reduced TNF-α (0.75- to 0.81-fold), IL-6 (0.77-fold), and IFN-γ (0.69-fold) levels; and increased TJ proteins levels, such as ZO-1 (4.06- to 5.27-fold), claudin-1 (3.33- to 5.14-fold), and occludin (6.46- to 11.82-fold). However, there was no significant difference between the levels of substance P (SP) and vasoactive intestinal peptide (VIP) in the control and WIRS groups. SNS regulated the composition of gut microbiota in WIRS mice. Conclusion The positive effects of SNS on WIRS could provide a theoretical basis to treat stress-related gastrointestinal disorders.

Comparative analysis of the effectiveness of local application of vitamin D3 and 5-aminosalicylic acid in experimental colitis

Introduction. At the moment in the Russian Federation there are no dosage forms with vitamin D3, allowing effective delivery and local effect on the focus of inflammation and the damaged area of the large intestine in inflammatory bowel disease (IBD). Among such dosage forms rectal suppositories are of the greatest interest. The aim of the study was to carry out a comparative analysis of the effectiveness of local administration of vitamin D3 and 5-aminosalicylic acid in experimental colitis. Materials and methods. Experimental colitis (EC) was modeled with oxazolone solution. Suppositories with vitamin D3 and with 5-ASA were applied per rectum every 12 h. Clinical status (DAI), morphometry, colon tissue injury index (TDI), myeloperoxidase (MPO) and TNF-α expression in the lesion were assessed. Results. In EC, DAI is increases, an ulcerative defect is fixed in the lesion of the colon, TDI, neutrophils (NF), lymphocytes (LC), eosinophils (EF), histiocytes (HC), plasma cells (PC), fibroblasts (FB), MPO and TNF-α expression are increased. Vitamin D3 administration reduces DAI, ulcer defect, TDI, MPO and TNF-α expression, the number of NF, EF, LC and PCs, and increases the number of GCs and FBs. Comparison of vitamin D3 and 5-ASA administration revealed comparable efficacy against DAI. Morphometric evaluation of colorectal lesions showed that under the conditions of vitamin D3 administration, in contrast to 5-ASC, less infiltration, edema, signs of healing and repair of ulcerous defects were fixed earlier in EC; MPO expression increased on the 6th day, TNF-α expression on the 4th day. The TDI index on the 4th and 6th days of EC decreased equally under the conditions of vitamin D3 and 5-ASC application. Discussion. The reduction of clinical severity and morphological signs of damage in the large intestine wall at EC against the background of using rectal suppositories with vitamin D3 could be due to pleiotropic effects of vitamin D3. Conclusion. The effect of vitamin D3 in original rectal suppositories is comparable with local application of 5-ASC at EC, it reduces severity of clinical signs, representation of cells involved in tissue destruction, TNF-α and MPO expression in the colon wall and increases representation of cells mediating reparation.

Lactate-driven macrophage polarization in the inflammatory microenvironment alleviates intestinal inflammation.

Lactate has long been considered an intermediate by-product of glucose metabolism. However, in recent years, accumulating evidence reveals that lactate has unique biological activities. In previous studies, lactate signaling was shown to inhibit inflammation. Furthermore, in vitro experiments have shown that lactate can promote the transformation of pro-inflammatory macrophages into anti-inflammatory macrophages. However, no in vivo studies have shown whether lactate can alleviate inflammation. RAW 264.7 macrophages were stimulated by LPS to induce an M1 phenotype, and cultured with low and high concentrations of lactate. The cells were then observed for phenotypic transformations and expression of inflammatory mediators and surface markers. The expression of inflammatory factors was also analyzed in the cell-free supernatant fraction. Further, a mouse model of DSS-induced colitis was established and treated with lactate. Colonic tissue injury was monitored by histopathological examinations. The in vitro experiments showed that lactate promoted the transformation of activated macrophages to M2 phenotype and decreased the expression of TLR4-mediated NF-κB signaling proteins and inflammatory factors. In the DSS-induced colitis mouse model, lactate promoted the phenotypic transformation of macrophages in colonic tissue, reduced inflammation and organ damage, inhibited the activation of TLR4/NF-κB signaling pathway, decreased the serum levels of pro-inflammatory factors, increased the expression of anti-inflammatory factors, promoted the repair of the intestinal mucosal barrier and reduced the severity of colitis. Lactate inhibits the TLR/NF-κB signaling pathway and the production of pro-inflammatory factors by promoting polarization of macrophages. In addition, lactate promotesthe repair of the intestinal mucosal barrier and protects intestinal tissue in inflammation. Furthermore, lactate is relatively safe. Therefore, lactate is a promising and effective drug for treating inflammation through immunometabolism regulation.

Soluble Protein Hydrolysate Ameliorates Gastrointestinal Inflammation and Injury in 2,4,6-Trinitrobenzene Sulfonic Acid-Induced Colitis in Mice

Inflammatory bowel diseases (IBD) are chronic, recurring gastrointestinal diseases that severely impair health and quality of life. Although therapeutic options have significantly expanded in recent years, there is no effective therapy for a complete and permanent cure for IBD. Well tolerated dietary interventions to improve gastrointestinal health in IBD would be a welcome advance especially with anticipated favorable tolerability and affordability. Soluble protein hydrolysate (SPH) is produced by the enzymatic hydrolysis of commercial food industry salmon offcuts (consisting of the head, backbone and skin) and contains a multitude of bioactive peptides including those with anti-oxidant properties. This study aimed to investigate whether SPH ameliorates gastrointestinal injury in 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced mouse colitis model. Mice were randomly assigned to four groups: Control (no colitis), Colitis, Colitis/CP (with control peptide treatment), and Colitis/SPH (with SPH treatment). Colitis was induced by cutaneous sensitization with 1% TNBS on day −8 followed by 2.5% TNBS enema challenge on day 0. Control peptides and SPH were provided to the mice in the Colitis/CP or Colitis/SPH group respectively by drinking water at the final concentration of 2% w/v daily from day −10 to day 4. Then, the colon was harvested on day 4 and examined macro- and microscopically. Relevant measures included disease activity index (DAI), colon histology injury, immune cells infiltration, pro- and anti-inflammatory cytokines and anti-oxidative gene expression. It was found that SPH treatment decreased the DAI score and colon tissue injury when compared to the colitis-only and CP groups. The protective mechanisms of SPH were associated with reduced infiltration of CD4+ T, CD8+ T and B220+ B lymphocytes but not macrophages, downregulated pro-inflammatory cytokines (tumor necrosis factor-α and interleukin-6), and upregulated anti-inflammatory cytokines (transforming growth factor-β1 and interleukin-10) in the colon tissue. Moreover, the upregulation of anti-oxidative genes, including ferritin heavy chain 1, heme oxygenase 1, NAD(P)H quinone oxidoreductase 1, and superoxide dismutase 1, in the colons of colitis/SPH group was observed compared with the control peptide treatment group. In conclusion, the protective mechanism of SPH is associated with anti-inflammatory and anti-oxidative effects as demonstrated herein in an established mice model of colitis. Clinical studies with SPH as a potential functional food for the prevention or as an adjuvant therapy in IBD may add an effective and targeted diet-based approach to IBD management in the future.

The mechanism of colon tissue damage mediated by HIF-1α/NF-κB/STAT1 in high-altitude environment.

The high-altitude environment damages the intestinal mucosal barrier, leading to a high incidence of intestinal diseases and seriously affects the working ability of people at high altitude. However, how high altitude induces intestinal mucosal barrier injury has not been well defined. The purpose of this study was to investigate the mechanism of colonic tissue injury induced by the influence of the high-altitude environment on the colonic microenvironment. Forty-eight SPF C57BL/6J mice were randomly divided into four groups: the control group and three other that were high-altitude exposure groups (Yushu, Qinghai; elevation: 4,010 m; 12 h, 24 h, 48 h). First, HE staining was used to observe the effect of the high-altitude environment on colon histomorphology of mice. The protein expression levels of claudin-1, occludin, and ZO-1 were analyzed by molecular biological methods. We found that altitude caused inflammatory damage to colon tissue. Intestinal hypoxia was measured with the hypoxic probe pimonidazole (PMDZ). Interestingly, we observed a decrease in the concentration of oxygen in the microenvironment in the colonic lumen. We sought to explore the mechanism of colonic mucosal barrier damage at different times when entering high altitude. The expression levels of hypoxia-inducible factors: HIF-1α, STAT1, and NF-κB and of inflammatory factors: IFN-γ, TNF-α, and IL-6 were significantly increased. This work highlights that the high-altitude environment leads to a reduction in the concentration of oxygen in the microenvironment of the colonic lumen, which disrupts the colonic mucosal barrier and ultimately induces and exacerbates intestinal injury.

Immunomodulatory effects of the Bifidobacterium longum BL-10 on lipopolysaccharide-induced intestinal mucosal immune injury.

The intestine is the largest digestive and immune organ in the human body, with an intact intestinal mucosal barrier. Bifidobacterium longum is the specific gut commensals colonized in the human gut for boosting intestinal immunity to defend against intestinal mucosal immune injury. In the LPS-induced intestinal injury model, the Bifidobacterium longum BL-10 was suggested to boost the intestinal immune. Detailly, compared with the LPS-induced mice, the BL10 group significantly reduced intestine (jejunum, ileum, and colon) tissue injury, pro-inflammatory cytokines (TNF-α, IFN-γ, IL-2, IL-6, IL-17, IL-22, and IL-12) levels and myeloperoxidase activities. Moreover, the B. longum BL-10 significantly increased the number of immunocytes (CD4+ T cells, IgA plasma cells) and the expression of tight junction protein (Claudin1 and Occludin). B. longum BL-10 regulated the body’s immune function by regulating the Th1/Th2 and Th17/Treg balance, which showed a greater impact on the Th1/Th2 balance. Moreover, the results also showed that B. longum BL-10 significantly down-regulated the intestinal protein expression of TLR4, p-IκB, and NF-κB p65. The B. longum BL-10 increased the relative abundance of the genera, including Lachnospiraceae_NK4A136_group and Clostridia_UCG-014, which were related to declining the levels of intestinal injury. Overall, these results indicated that the B. longum BL-10 had great functionality in reducing LPS-induced intestinal mucosal immune injury.

E.faecium QH06 alleviates TNBS-induced colonic mucosal injury in rats

To investigate the effect of Enterococcus faecium QH06 on TNBS-induced ulcerative colitis (UC) in rats and explore the mechanisms in light of intestinal flora and intestinal immunity. Thirty-six male Wistar rats were randomized equally into control group, UC model group, and E.faecium QH06 intervention group. The rats in the latter two groups were subjected to colonic enema with 5% TNBS/ethanol to induce UC, followed by treatment with intragastric administration of distilled water or E.faecium QH06 at the dose of 0.21 g/kg. After 14 days of treatment, the rats were examined for colon pathologies with HE staining. The mRNA and protein expression levels of IL-4, IL-10, IL-12, and IFN-γ in the colon tissues were detected using RT-qPCR and ELISA, and the expression of TLR2 protein was detected with immunohistochemistry and ELISA. Illumina Miseq platform was used for sequencing analysis of the intestinal flora of the rats with bioinformatics analysis. The correlations of the parameters of the intestinal flora with the expression levels of TLR2 and cytokines were analyzed. The rats with TNBS- induced UC showed obvious weight loss (P < 0.01) and severe colon tissue injury with high pathological scores (P < 0.01). The protein expression levels of IFN-γ, IL-12, and TLR2 (P < 0.01) and the mRNA expression levels of IFN-γ, IL-12 and IL-10 (P < 0.05) were significantly increased in the colon tissues of the rats with UC. Illumina Miseq sequence analysis showed that in UC rats, the Shannon index (P < 0.05) ACE (P < 0.01)and Chao (P < 0.05) index for the diversity of intestinal flora both decreased with a significantly increased abundance of Enterobacteriaceae (P < 0.01) and a lowered abundance of Burkholderiaceae (P < 0.05). Compared with the UC rats, the rats treated with E. faecium QH06 showed obvious body weight gain (P < 0.05), lessened colon injuries, lowered pathological score of the colon tissue (P < 0.05), decreased protein expressions of IFN- γ, IL- 12, and TLR2 and mRNA expressions of IFN- γ and IL-12 (P < 0.01 or 0.05), and increased protein expressions of IL- 4 (P < 0.05). The Shannon index ACE (P < 0.05) and Chao (P < 0.05) index of intestinal microflora were significantly increased, the abundance of Enterobacteriaceae was lowered and that of Burkholderiaceae and Rikenellaceae was increased in E.faecium QH06- treated rats (P < 0.01 or 0.05). Correlation analysis showed that IFN-γ was positively correlated with the abundance of Enterobacteriaceae, and IFN-γ was negatively correlated with the abundance of Prevotellaceae, Desulfovibrionaceae, norank_o_Mollicutes_RF39 and Clostridiales_vadinBB60_group; TLR2 was negatively correlated with Clostridiales_vadinBB60_group, norank_o_Mollicutes_RF39 and Prevotellaceae. E.faecium QH06 can alleviate TNBS-induced colonic mucosal injury in rats, and its effect is mediated possibly by increasing the abundance of SCFA-producing bacteria such as Prevotellaceae and inhibiting abnormal immune responses mediated by TLR2.

Hydroxysafflor yellow A protects against ulcerative colitis via suppressing TLR4/NF-κB signaling pathway.

Hydroxysafflower yellow A (HSYA) protects against acute kidney injury through TLR4/NF-κB pathway. However, the effect and potential mechanism of HSYA in ulcerative colitis (UC) have been rarely reported, which is thus investigated in this research. An in vivo UC model was established by oral administration of 5% dextran sulfate sodium (DSS) in Sprague-Dawley rats. After HSYA treatment, the daily body weight and colon length of rats were measured. Then rat colon tissues, myeloperoxidase (MPO) activity, and the levels of inflammatory cytokines were examined by histopathological examination (HE) staining, immunohistochemistry, ultraviolet spectrophotometry, and enzyme-linked immune sorbent assay (ELISA) respectively. The activated TLR4/NF-κB pathway was detected by Western blot. RAW 264.7 cell viability was detected by MTT assay after lipopolysaccharide (LPS) treatment, and ELISA and Western blot were performed again to investigate the effects of HSYA on LPS-treated cells. DSS administration increased body weight and colon length of rats and induced colon tissue injury. DSS or LPS treatment up-regulated the levels of TNF-α, IL-1β, and IL-6 and activated TLR4/NF-κB pathway of colon tissues and cells, respectively. HSYA partially reversed the above effect of DSS and LPS treatment, and the effects of the drug were improved with the dosage. Taken together, HSYA alleviates UC by suppressing TLR4/NF-κB signaling pathway, which may provide a new insight for the treatment of UC.

Curcumin ameliorated dextran sulfate sodium-induced colitis via regulating the homeostasis of DCs and Treg and improving the composition of the gut microbiota

Abnormal dendritic cells (DCs) and Treg cell polarisation and dysbiosis of the intestinal flora are typical features of the pathogenesis of inflammatory bowel disease (IBD). The natural compound curcumin has good anti-inflammatory properties. However, it is unclear whether curcumin effectively ameliorates IBD by regulating the homeostasis of DCs, Treg and gut microbiota. In this study, mice colitis induced by dextran sulfate sodium was orally administrated with curcumin (100 mg/kg/day) for 7 days. Consequently, the index of colonic weight significantly decreased, and body weight, colonic weight, colonic length and colonic tissue injury improved significantly; the percentage of Treg increased significantly, inflammatory DCs and pro-inflammatory cytokines decreased significantly, and the composition of gut microbiota were improved. In addition, curcumin inhibited the activation of PI3K/Akt signaling pathway in colitis mice. These data suggested that curcumin ameliorated colitis by regulating DCs, Treg and gut microbiota, and the underlying mechanism is related to PI3K/Akt pathway inhibition.

Protection by microRNA-7a-5p Antagomir Against Intestinal Mucosal Injury Related to the JNK Pathway in TNBS-Induced Experimental Colitis.

Increasing evidence shows that microRNA-7a-5p (miR-7a-5p) plays an important role in regulating the inflammatory process in inflammatory bowel disease (IBD). How miR-7a-5p contributes to this process is poorly defined. The purpose of this study was to examine whether miR-7a-5p regulates 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced inflammatory responses via the JNK pathway. Colitis was induced in male mice by intracolonic administration of TNBS; mice were divided into 3 groups: normal control (NC), TNBS, and miR-7a-5p antagomir-treated group. Inflammatory responses were estimated by disease activity index (DAI) and histological scores. The relative expressions of miR-7a-5p and tight junction protein, ZO-1, were detected by RT-qPCR. Western blot assays were used to estimate the level of JNK pathway proteins and ZO-1. After miRNA-antagomir injection, the extent of colonic tissue injury and expression levels of ZO-1 and JNK in intestinal tissue were compared. miR-7a-5p and p-JNK expression were higher in the intestinal tissue of the TNBS group as compared to NC. Inhibition of the expression of miR-7a-5p resulted in significantly decreased expression of p-JNK but increased expression of ZO-1 and promoted the recovery of intestinal mucosa. This work demonstrates a correlation between the JNK pathway and miR-7a-5p in TNBS-induced experimental colitis in mice, which may provide a new research direction for the treatment of IBD.