Hapten-induced model of chronic inflammation and ulceration in the rat colon

Moxibustion ameliorates chronic inflammatory visceral pain via spinal circRNA-miRNA-mRNA networks: a central mechanism study

This study aimed to unveil the central mechanism of moxibustion treating chronic inflammatory visceral pain (CIVP) from the angle of circRNA-miRNA-mRNA networks in the spinal cord. The rat CIVP model was established using a mixture of 5% (w/v) 2,4,6-trinitrobenzene sulfonic acid and 50% ethanol at a volume ratio of 2:1 via enema. Rats in the moxibustion group received herb-partitioned moxibustion at Tianshu (ST25, bilateral) and Qihai (CV6) points. The abdominal withdrawal reflex (AWR), mechanical withdrawal threshold (MWT), and thermal withdrawal latency (TWL) were adopted for pain behavior observation and pain sensitivity assessment. The circRNA, miRNA, and mRNA expression profiles were detected using the high-throughput sequencing technique. Relevant databases and bioinformatics analysis methods were used to screen for differentially expressed (DE) RNAs and build a circRNA-miRNA-mRNA (competing endogenous RNA) ceRNA regulatory network. The real-time quantitative PCR was employed to verify the sequencing result. CIVP rat models had a significantly higher AWR and lower TWL and MWT than normal rats. Between normal and model rats, there were 103 DE-circRNAs, 16 DE-miRNAs, and 397 DE-mRNAs in the spinal cord. Compared with the model group, the moxibustion group had a lower AWR and higher TWL and MWT; between these two groups, there were 118 DE-circRNAs, 15 DE-miRNAs, and 804 DE-mRNAs in the spinal cord. Two ceRNA networks were chosen to be verified. As a result, moxibustion's analgesic effect on visceral pain in CIVP rats may be associated with regulating the circRNA_02767/rno-miR-483-3p/Gfap network in the spinal cord and improving central sensitization.

Protective effect of tomato pomace extract encapsulated in combination with probiotics against indomethacin induced enterocolitis

Tomato pomace (TP), an antioxidant-rich byproduct, may be suitable for noble applications. The regulation of ROS generation and the anti-inflammatory response can help to prevent ulceration. The purpose of this study was to examine TP for antioxidants, in silico anti-inflammatory properties, and its potential to protect against ulceration and erosion triggered by indomethacin. Tomato pomace extract (TPE) was encapsulated either alone or with probiotics to maximize its potential effect. These microcapsules were investigated in indomethacin-treated rats. TPE demonstrated antioxidant activity as well as high levels of carotenoids (15 mg/g extract) and polyphenols. Because of their binding affinity as well as hydrophobic and hydrogen bond interactions with the active sites of TNF-α and IL-1β inflammatory cytokines, ellagic acid and rutin may be implicated in the anti-inflammatory effect of TPE, according to the docking study. TPE microcapsules, either alone or in combination with probiotics, demonstrated a protective effect against enterocolitis by reducing oxidative stress and inflammation, as evidenced by the decrease in stomach and intestinal MDA, NO, IL-1β, IL-6, and TNF-α levels and the increase in CAT, SOD, and GSH activities. The produced microcapsules are suggested to be promising candidates for protection against gastric ulcers and erosion.

Cinnamic Acid Ameliorates Acetic Acid-induced Inflammatory Response through Inhibition of TLR-4 in Colitis Rat Model

BACKGROUND

Cinnamic acid, an active compound in cinnamon spp., has anti-inflammatory and antioxidant characteristics and is favorable in managing inflammatory bowel diseases.

OBJECTIVES

Evaluate cinnamic acid's effects on colitis in rats.

METHODS

To induce colitis in experimental rats, excluding the sham group, a 4% intrarectal solution of acetic acid was administered. The rats were then given oral doses of cinnamic acid at 30, 45, and 90 mg/kg for two days. The animals were assessed for macroscopic and microscopic changes, and the levels of inflammatory mediators such as tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and myeloperoxidase (MPO) were measured using Eliza kits. Additionally, real-time PCR was performed to examine the gene level of toll-like receptor 4 (TLR-4) in the colon.

RESULTS

Effective reduction of inflammation in acetic acid-induced colitis was achieved through Cinnamic acid administration at doses of 45 and 90 mg/kg. The decrease was achieved by inhibiting the activities of TNF-α, IL-6, and MPO while downregulating the expression of TLR-4. It is important to note that macroscopic and microscopic evaluations were significant in determining the effectiveness of cinnamic acid in reducing inflammation.

CONCLUSION

Downregulation of inflammatory cytokines and TLR-4 expression may contribute to cinnamic acid's anti-inflammatory effect.

Identification of arginine-vasopressin receptor 1a (Avpr1a/AVPR1A) as a novel candidate gene for chronic visceral pain

Chronic abdominal pain in the absence of ongoing disease is the hallmark of disorders of gut-brain interaction (DGBIs), including irritable bowel syndrome (IBS). While the etiology of DGBIs remains poorly understood, there is evidence that both genetic and environmental factors play a role. In this study, we report the identification and validation of Avpr1a as a novel candidate gene for visceral hypersensitivity (VH), a primary peripheral mechanism underlying abdominal pain in DGBI/IBS. Comparing two C57BL/6 (BL/6) substrains (C57BL/6NTac and C57BL/6J) revealed differential susceptibility to the development of chronic VH following intrarectal zymosan (ZYM) instillation, a validated preclinical model for post-inflammatory IBS. Using whole genome sequencing, we identified a SNP differentiating the two strains in the 5' intergenic region upstream of Avpr1a, encoding the protein arginine-vasopressin receptor 1A (AVPR1A). We used behavioral, histological, and molecular approaches to identify distal colon-specific gene expression differences and neuronal hyperresponsiveness covarying with Avpr1a genotype and VH susceptibility. While the two BL/6 substrains did not differ across other gastrointestinal (GI) phenotypes (e.g., GI motility), VH-susceptible BL/6NTac mice had higher colonic Avpr1a mRNA and protein expression. Moreover, neurons of the enteric nervous system were hyperresponsive to the AVPR1A agonist AVP, suggesting a role for enteric neurons in the pathology underlying VH. These results parallel our findings that patients' colonic Avpr1a mRNA expression was higher in patients with higher pain ratings. Taken together, these findings implicate differential regulation of Avpr1a as a novel mechanism of VH-susceptibility as well as a potential therapeutic target specific to VH.

Phytochemical analysis of Origanum majorana L. extract and investigation of its antioxidant, anti-inflammatory and immunomodulatory effects against experimentally induced colitis downregulating Th17 cells

ETHNOPHARMACOLOGICAL RELEVANCE

Origanum majorana L. is a member of the Lamiaceae family and is commonly used in Egyptian cuisine as a seasoning and flavor enhancer. It is also recognized as a well-known traditional medicine in Egypt and is widely used for treating abdominal colic due to its antispasmodic properties. However, the protective effects of Origanum majorana L. against ulcerative colitis and its underlying mechanisms remain unclear.

AIM OF THE STUDY

This study aimed to identify the biologically active components present in methanol extracts of Origanum majorana L. using gas chromatography/mass spectrometry (GC/MS). Additionally, it aimed to investigate the therapeutic effects of these extracts on acetic acid-induced ulcerative colitis and elucidate the potential mechanisms involved.

MATERIALS AND METHODS

We conducted a GC-MS analysis of the methanolic extract obtained from Origanum majorana L. Thirty-two male rats were included in the study and divided into four experimental groups, with eight rats in each group: sham, UC, UC + O. majorana, and UC sulfasalazine. After euthanizing the rats, colon tissue samples were collected for gross and microscopic examinations, assessment of oxidative stress, and molecular evaluation. GC-MS analysis identified 15 components in the extracts. Pretreatment with O. majorana L. extract and sulfasalazine significantly improved the disease activity index (DAI) and resulted in notable improvements in macroscopic and microscopic colon findings. Additionally, both treatments demonstrated preventive effects against colonic oxidative damage by reducing the levels of malondialdehyde (MDA) and increasing the levels of the antioxidant systems superoxide dismutase (SOD), catalase (CAT), and glutathione (GSH), which operate through the Nrf2/HO-1 signaling pathway. Moreover, these treatments downregulated the colonic inflammatory cascade by inhibiting NFκB, TNFα, IL-1β, IL6, IL23, IL17, COX-2, and iNOS, subsequently leading to downregulation of the JAK2/STAT3 signaling pathway and a decrease in the Th17 cell response. Furthermore, a reduction in the number of apoptotic epithelial cells that expressed caspase-3 was observed.

CONCLUSION

pretreatment with O. majorana L. extract significantly ameliorated acetic acid-induced ulcerative colitis. This effect could be attributed to the protective, antioxidant, anti-inflammatory, and anti-apoptotic properties of the extract.

TNF-α Mediated the Disruption of Hepatic Tight Junction Expression in Blood-Biliary Barrier of Colitis via Downregulating PI3K/AKT Signaling Pathway

Hepatocyte tight junctions (TJ) constituted blood-biliary barrier is the most important hepatic barrier for separating bile from the bloodstream, disruption or dysfunction of TJ barrier is involved in hepatobiliary manifestations of colitis, but the underlying mechanism is still not clear. This study aims to investigate the effect and underlying mechanism of tumor necrosis factor alpha (TNF-α) on hepatic TJ protein expression in blood-biliary barrier and identify its role in the pathogenesis of acute colitis-related cholestasis. Acute colitis rat model was induced by trinitrobenzene sulfonic acid (TNBS) intra-colonic administration. TJs expression of blood-biliary barrier was tested in colitis rats, the serum TNF-α level was also determined in order to elucidate the correlation of TNF-α and TJs. HepaRG cells were used to investigate the effect of TNF-α on TJs, and the phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT) signaling pathway were also evaluated in rats and TNF-α treated HepaRG cells. Acute colitis was induced in rats at 5 d post TNBS, which is accompanied with cholestasis-like alteration. Serum TNF-α level was increased in colitis rats and positively correlated with the alteration of total bile acids and bilirubin, marked decrease in TJs was found in TNF-α treated HepaRG cells and the rats, down-regulated PI3K/AKT signaling pathway were also identified in TNF-α treated HepaRG cells and the rats. The study concluded that serum TNF-α mediated the down-regulation of PI3K/AKT signaling pathway, which contributed to the reduction of TJ protein expression in acute colitis-related intrahepatic cholestasis. These findings suggest that TNF-α plays an important role in the pathogenesis of intrahepatic cholestasis of colitis.

Inhibition of Soluble Stem Cell Factor Promotes Intestinal Mucosal Repair

BACKGROUND

Incidences of inflammatory bowel disease (IBD), including Crohn's disease and ulcerative colitis, are escalating worldwide and can be considered a global public health problem. Given that the gold standard approach to IBD therapeutics focuses on reducing the severity of symptoms, there is an urgent unmet need to develop alternative therapies that halt not only inflammatory processes but also promote mucosal repair. Previous studies have identified increased stem cell factor (SCF) expression in inflamed intestinal mucosal tissues. However, the role that SCF plays in mediating intestinal inflammation and repair has not been explored.

METHODS

Changes in the expression of SCF were evaluated in the colonic tissue of healthy mice and during dextran sodium sulfate (DSS)-induced colitis. Furthermore, mucosal wound healing and colitis severity were analyzed in mice subjected to either mechanical biopsy or DSS treatment, respectively, following intestinal epithelial cell-specific deletion of SCF or anti-SCF antibody administration.

RESULTS

We report robust expression of SCF by intestinal epithelial cells during intestinal homeostasis with a switch to immune cell-produced SCF during colitis. Data from mice with intestinal epithelial cell-specific deletion of SCF highlight the importance of immune cell-produced SCF in driving the pathogenesis of colitis. Importantly, antibody-mediated neutralization of total SCF or the specific SCF248 isoform decreased immune cell infiltration and enhanced mucosal wound repair following biopsy-induced colonic injury or DSS-induced colitis.

CONCLUSIONS

These data demonstrate that SCF functions as a pro-inflammatory mediator in mucosal tissues and that specific neutralization of SCF248 could be a viable therapeutic option to reduce intestinal inflammation and promote mucosal wound repair in individuals with IBD.

Effect of aqueous extract of Trigonellafoenum-graecum L. seeds on Acetic acid- induced Ulcerative colitis in rats

Background: Ulcerative colitis (UC) is an inflammatory bowel disorder affecting the colonic mucosa, characterized by intense inflammation and mucosal damage. The present study aimed to evaluate the protective effect of the Trigonellafoenum-graecum L. (TFG) seeds in acetic acid-induced UC in rats. Materials and Methods: Male rats (n=30) were distributed into 5 groups as normal control, UC, standard, and two test groups. Colitis was induced by acetic acid in all the groups except the normal control group. Normal control and UC group received distilled water, the standard group was administered sulfasalazine at 100mg/kg body weight (bw), and test groups, TFG-I, and TFG-II received TFG seed extract at 500 and 1000 mg/kg bw, respectively. The duration of treatment was 7 days, and colitis was induced on day 8. Animals were sacrificed on day 9 and colonic tissue was dissected and collected for biochemical, molecular, and histological analysis. Results: The disease activity index score in standard, TFG-I, and TFG-II (3.33±0.21, 2.66±0.21, and 3.50±0.22) was significantly lesser (P<0.05) than scores in the UC group (4±0.01). The macroscopic score indicating the intensity of mucosal inflammation was significantly decreased (P≤ 0.01) to4.0±0.25, 3.16±0.30, and 3.83±0.40 in standard, TFG-I, and TFG-II groups, respectively compared to the UC group (4.66±0.21). Similarly, there was a significant reduction (P≤0.05) in histological scores of the standard, TFG-I, TFG-II (3.5±0.34, 1.25±0.34, 3.25±0.34) groups compared to the UC group (4.75±0.34). Biochemical assessment in the standard and test groups showed significant increase (P<0.05) in total protein, reduced glutathione (GSH), catalase (CAT), superoxide dismutase (SOD) levels whereas significant reduction (P<0.01) in malondialdehyde (MDA) levels compared to UC group. The pro-inflammatory cytokine TNF-α levels were significantly decreased (P<0.01) in standard, TFG-I, and TFG-II (-1.75±0.007, -0.27±0.17 and -0.51±0.002) when compared to the UC group (0.20±0.02). Conclusion: The study demonstrates the ability of TFG seeds in reducing the inflammatory and oxidative stress induced mucosal damage in acetic acid-induced UC in rats.

Acertannin Prevented Dextran Sulfate Sodium-induced Colitis by Inhibiting the Colonic Expression of IL-23 and TNF-α in C57BL/6J Mice

The present study investigates the effects of acertannin on colitis induced by dextran sulfate sodium (DSS) and changes in the colonic levels of the cytokines interleukin (IL)-1β, IL-6, IL-10, IL-23, tumor necrosis factor (TNF)-α, the chemokine monocyte chemoattractant protein (MCP)-1, and vascular endothelial growth factor (VEGF).We examine the following: inflammatory colitis was induced in mice by 2% DSS drinking water given ad libitum for 7 days. Red blood cell, platelets, and leukocyte counts and hematocrit (Ht), hemoglobin (Hb), and colonic cytokine and chemokine levels were measured. The disease activity index (DAI) was lower in DSS-treated mice orally administered acertannin (30 and 100 mg/kg) than in DSS-treated mice. Acertannin (100 mg/kg) inhibited reductions in the red blood cell count and Hb and Ht levels in DSS-treated mice. Acertannin prevented DDS-induced mucosal membrane ulceration of the colon and significantly inhibited the increased colonic levels of IL-23 and TNF-α. Our findings suggest that acertannin has potential as a treatment for inflammatory bowel disease (IBD).

Chemically-induced trout model of acute intestinal inflammation using TNBS

Chemically-induced models of intestinal inflammation are a useful tool for the study of immune responses and inflammation. Although well established in mammals, application of these models is currently limited in teleosts. Based on a variety of factors, including genetic diversity, known toxicological sensitivity, and economic importance, we propose salmonids as a model family of fishes for studying intestinal inflammation. We present a rainbow trout model of chemically-induced intestinal inflammation using 2,4,6-trinitrobenzene sulfonic acid (TNBS), assessed through histological analysis of primary and secondary intestinal folding, enterocyte morphology, goblet cell size and frequency, tissue layer thickness, and immune cell infiltration. Twenty-four hours after treatment with one of three concentrations of TNBS, trout developed classic signs of intestinal inflammation, including notably increased thickness of primary and secondary folds, and increased immune cell infiltration as compared to controls. This study provides a simple, reproducible model of rapid TNBS-induction of moderate intestinal inflammation.

Renshen Baidu Powder Attenuated Intestinal Inflammation and Apoptosis in Ulcerative Colitis Rats through the Inhibition of PI3K/AKT/NF-κB Signaling Pathway

Objective

Renshen Baidu Powder (RBP) is a famous classic compound of traditional Chinese medicine (TCM) and is commonly used for treating ulcerative colitis (UC). However, the pharmacological mechanism of RBP in treating UC remains unclear. This study investigates the possible mechanism of RBP for UC treatment by network pharmacological analysis and rat validation.

Methods

First, the main chemical constituents of RBP were identified using ultrahigh-performance liquid chromatography quadrupole Orbitrap high-resolution mass spectrometry (UHPLC-Q-Orbitrap-HRMS). Then, we obtained targets of identified compounds from the SwissTargetPrediction database and targets associated with UC from GeneCards database. Furthermore, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) were used to analyze the metabolism-related signaling pathways affected by RBP. Hematoxylin-eosin (HE) staining was used to observe the pathological change of colon in UC rats after treating RBP, and terminal deoxynucleotidyl-transferase (TdT)-mediated dUTP Nick end labeling (TUNEL) staining was used to detect apoptosis after RBP treatment. The enzyme-linked immunosorbent assay (ELISA) was employed to evaluate cytokine levels of TNF-α, IL-1β, and IL-6. The protein expressions of Bax, Bcl-2, PI3K, AKT, and NF-κB in colonic tissue were detected using immunohistochemistry (IHC). Real-time quantitative polymerase chain reaction (RT-QPCR) was employed to evaluate mRNA expression of PI3K, AKT, and NF-κB.

Results

We found a total of 24 main compounds and 329 potential targets related to UC. According to KEGG results, 3 main pathways were identified as responsible for UC, including PI3K-AKT, HIF-1, and VEGF signaling pathway. Animal experiments showed that RBP treatment significantly attenuated colon damage in rats with UC. Mechanistically, RBP could inhibit PI3K/AKT/NF-κB pathway; decrease cell apoptosis; and downregulate the expression of TNF-α, IL-1β, and IL-6.

Conclusions

This study demonstrated that RBP may exert anti-inflammatory and antiapoptotic therapeutic benefits in UC by regulating the PI3K/AKT/NF-κB signaling pathways, providing a scientific basis for understanding the mechanism of RBP against UC.

Sinapic Acid Ameliorates Acetic Acid-Induced Ulcerative Colitis in Rats by Suppressing Inflammation, Oxidative Stress, and Apoptosis

Background: Ulcerative colitis (UC) is a long-term condition which results in inflammation and ulcers of the colon and rectum. The key indications of active disease are abdominal pain and diarrhea mixed with blood. Aims: We explore the underlying colon protective mechanism of sinapic acid (SA) against acetic acid (AA) induced ulcerative colitis in rats. The implications of inflammation, oxidative stress, and apoptosis are studied. Methodology: Twenty-four rats were distributed into four categories, normal control (NC), ulcerative colitis (UC), ulcerative Colitis with SA 40 mg/kg (SA 40 mg/kg + AA), and ulcerative colitis with prednisolone (PRDL 10 mg/kg + AA), and were pretreated orally with saline, saline and SA (40 mg/kg/day) or PRDL (10 mg/kg/day) respectively, for 7 days. UC was prompted by trans-rectal administration of 4% AA on the 5th day, colon tissues were surgically removed for gross morphology and histological inspection, oxidative stress, and inflammatory markers and immunoblot analysis of Bax, caspase-3, and Bcl-2. Results: Macroscopic and histological inspection demonstrated that both SA 40 mg/kg and PRDL (10 mg/kg/day) significantly ameliorates colonic injuries. In addition, both pretreatments significantly ameliorates AA-induced UC, oxidative stress, as indicated by suppressed malondialdehyde (MDA), nitric oxide (NO) levels and restoring antioxidant/oxidant balance as indicated by catalase and glutathione levels, suppressed inflammation via inhibiting cytokines TNF-α, IL-6, inflammatory markers MPO, PGE₂, COX-2 and NF-κB and inhibiting the protein expression of Bax and caspase-3 apoptotic protein and increasing the anti-apoptotic protein, Bcl-2 thereby inhibiting apoptosis. Conclusion: Sinapic acid significantly ameliorates AA induced UC in rats by suppressing inflammation, oxidative stress, and apoptosis in colonic tissues which exhibits its potential for the management of UC.

The Effect of Serine Protease Inhibitors on Visceral Pain in Different Rodent Models With an Intestinal Insult

Background: Serine proteases are believed to play a key role in the origin of abdominal pain in IBD and IBS. We previously demonstrated a reduction of visceral pain in a post-inflammatory IBS rat model after a single intraperitoneal or intracolonic administration of a serine protease inhibitor. The aim of this study was to investigate the efficacy of serine protease inhibition on visceral pain in two different animal models involving a colonic insult based either on acute inflammation or on neonatal irritation. Moreover, protease profiling was explored in the acute colitis model. Methods: An acute 2,4,6-trinitrobenzenesulphonic acid (TNBS) colitis rat model and a chronic neonatal acetic acid mouse model were used in this study. Visceral sensitivity was quantified by visceromotor responses (VMRs) to colorectal distension, 30 min after intraperitoneal administration of the serine protease inhibitors nafamostat, UAMC-00050 or their vehicles. Colonic samples from acute colitis rats were used to quantify the mRNA expression of a panel of serine proteases and mast cell tryptase by immunohistochemistry. Finally, proteolytic activities in colonic and fecal samples were characterized using fluorogenic substrates. Key Results: We showed a significant and pressure-dependent increase in visceral hypersensitivity in acute colitis and neonatal acetic acid models. UAMC-00050 and nafamostat significantly reduced VMRs in both animal models. In acute colitis rats, the administration of a serine protease inhibitor did not affect the inflammatory parameters. Protease profiling of these acute colitis animals revealed an increased tryptase immunoreactivity and a downregulation of matriptase at the mRNA level after inflammation. The administration of UAMC-00050 resulted in a decreased elastase-like activity in the colon associated with a significantly increased elastase-like activity in fecal samples of acute colitis animals. Conclusion: In conclusion, our results suggest that serine proteases play an important role in visceral hypersensitivity in an acute TNBS colitis model in rats and a neonatal acetic acid model in mice. Moreover, we hypothesize a potential mechanism of action of UAMC-00050 via the alteration of elastase-like proteolytic activity in acute inflammation. Taken together, we provided fundamental evidence for serine protease inhibitors as a promising new therapeutic strategy for abdominal pain in gastrointestinal diseases.

Chemically Induced Colitis-Associated Cancer Models in Rodents for Pharmacological Modulation: A Systematic Review

Animal models for colitis-associated colorectal cancer (CACC) represent an important tool to explore the mechanistic basis of cancer-related inflammation, providing important evidence that several inflammatory mediators play specific roles in the initiation and perpetuation of colitis and CACC. Although several original articles have been published describing the CACC model in rodents, there is no consensus about the induction method. This review aims to identify, summarize, compare, and discuss the chemical methods for the induction of CACC through the PRISMA methodology.

METHODS

We searched MEDLINE via the Pubmed platform for studies published through March 2021, using a highly sensitive search expression. The inclusion criteria were only original articles, articles where a chemically-induced animal model of CACC is described, preclinical studies in vivo with rodents, and articles published in English.

RESULTS

Chemically inducible models typically begin with the administration of a carcinogenic compound (as azoxymethane (AOM) or 1,2-dimethylhydrazine (DMH)), and inflammation is caused by repeated cycles of colitis-inducing agents (such as 2,4,6-trinitrobenzenesulfonic acid (TNBS) or dextran sulfate sodium (DSS)). The strains mostly used are C57BL/6 and Balb/c with 5-6 weeks. To characterize the preclinical model, the parameters more used include body weight, stool consistency and morbidity, inflammatory biomarkers such as tumor necrosis factor (TNF)-α, interleukin (IL)-6 and IL-1β, angiogenesis markers such as proliferating cell nuclear antigen (PCNA), marker of proliferation Ki-67, and caspase 3, the presence of ulcers, thickness or hyperemia in the colon, and histological evaluation of inflammation.

CONCLUSION

The AOM administration seems to be important to the CACC induction method, since the carcinogenic effect is achieved with just one administration. DSS has been the more used inflammatory agent; however, the TNBS contribution should be more studied, since it allows a reliable, robust, and a highly reproducible animal model of intestinal inflammation.

Ethanolic extract from Lepidium virginicum L. ameliorates DNBS-induced colitis in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Lepidium virginicum L. (Brassicaceae) is a plant widely used in traditional Mexican medicine as an expectorant, diuretic, and as a remedy to treat diarrhea and dysentery, infection-derived gastroenteritis. However, there is no scientific study that validates its clinical use as an anti-inflammatory in the intestine.

AIM OF THE STUDY

This study aimed to investigate the anti-inflammatory properties of the ethanolic extract of Lepidium virginicum L. (ELv) in an animal model of inflammatory bowel disease (IBD)-like colitis.

MATERIALS AND METHODS

The 2,4-dinitrobenzene sulfonic acid (DNBS) animal model of IBD was used. Colitis was induced by intrarectal instillation of 200 mg/kg of DNBS dissolved vehicle, 50% ethanol. Control rats only received the vehicle. Six hours posterior to DNBS administration, ELv (3, 30, or 100 mg/kg) was administered daily by gavage or intraperitoneal injection. The onset and course of the inflammatory response were monitored by assessing weight loss, stool consistency, and fecal blood. Colonic damage was evaluated by colon weight/length ratio, histopathology, colonic myeloperoxidase (MPO) activity, and gene expression of proinflammatory cytokines, including tumor necrosis factor-alpha (TNF-α), interleukin-1beta (IL-1β), chemokine C-X-C motif ligand 1 (CXCL-1), and interleukin-6 (IL-6).

RESULTS

Rats treated with DNBS displayed significant weight loss, diarrhea, fecal blood, colon shortening, a significant increase in immune cell infiltration and MPO activity, as well as increased proinflammatory cytokine expression. Intraperitoneal administration of ELv significantly reduced colon inflammation, whereas oral treatment proved to be ineffective. In fact, intraperitoneal ELv significantly attenuated the clinical manifestations of colitis, immune cell infiltration, MPO activity, and pro-inflammatory (CXCL-1, TNF-α, and IL-1β) gene expression in a dose-dependent manner.

CONCLUSION

Traditional medicine has employed ELv as a remedy for common infection-derived gastrointestinal symptoms; however, we hereby present the first published study validating its anti-inflammatory properties in the mitigation of DNBS-induced colitis.

Bacillus amyloliquefaciens Enriched Camel Milk Attenuated Colitis Symptoms in Mice Model

Fermented camel’s milk has various health beneficial prebiotics and probiotics. This study aimed to evaluate the preventive efficacy of Bacillus amyloliquefaciens enriched camel milk (BEY) in 2-, 4- and 6-Trinitrobenzenesulfonic acid (TNBS)-induced colitis mice models. To this end, the immune modulatory effects of Bacillus amyloliquefaciens (BA) on TNF-α challenged HT29 colon cells were estimated using the cell proliferation and cytokines ELISA method. BEY was prepared using the incubation method and nutritional value was quantified by comparing it to commercial yogurt. Furthermore, TNBS-induced colitis was established and the level of disease index, pathological scores, and inflammatory markers of BEY-treated mice using macroscopic and microscopic examinations, qPCR and immunoblot were investigated. The results demonstrate that BA is non-toxic to HT29 colon cells and balanced the inflammatory cytokines. BEY reduced the colitis disease index, and improved the body weight and colon length of the TNBS-induced mice. Additionally, Myeloperoxidase (MPO) and pro-inflammatory cytokines (IL1β, IL6, IL8 and TNF-α) were attenuated by BEY treatment. Moreover, the inflammatory progress mRNA and protein markers nuclear factor kappa B (NFκB), phosphatase and tensin homolog (PTEN), proliferating cell nuclear antigen (PCNA), cyclooxygenase-2 (COX-2) and occludin were significantly down-regulated by BEY treatment. Interestingly, significant suppression of PCNA was observed in colonic tissues using the immunohistochemical examination. Treatment with BEY increased the epigenetic (microRNA217) interactions with PCNA. In conclusion, the BEY clearly alleviated the colitis symptoms and in the future could be used to formulate a probiotic-based diet for the host gut health and control the inflammatory bowel syndrome in mammals.

Chronic Experimental Model of TNBS-Induced Colitis to Study Inflammatory Bowel Disease

Background: Inflammatory bowel disease (IBD) is a world healthcare problem. In order to evaluate the effect of new pharmacological approaches for IBD, we aim to develop and validate chronic trinitrobenzene sulfonic acid (TNBS)-induced colitis in mice. Methods: Experimental colitis was induced by the rectal administration of multiple doses of TNBS in female CD-1 mice. The protocol was performed with six experimental groups, depending on the TNBS administration frequency, and two control groups (sham and ethanol groups). Results: The survival rate was 73.3% in the first three weeks and, from week 4 until the end of the experimental protocol, the mice’s survival remained unaltered at 70.9%. Fecal hemoglobin presented a progressive increase until week 4 (5.8 ± 0.3 µmol Hg/g feces, p < 0.0001) compared with the ethanol group, with no statistical differences to week 6. The highest level of tumor necrosis factor-α was observed on week 3; however, after week 4, a slight decrease in tumor necrosis factor-α concentration was verified, and the level was maintained until week 6 (71.3 ± 3.3 pg/mL and 72.7 ± 3.6 pg/mL, respectively). Conclusions: These findings allowed the verification of a stable pattern of clinical and inflammation signs after week 4, suggesting that the chronic model of TNBS-induced colitis develops in 4 weeks.

LncRNA-miRNA-mRNA Network Analysis Reveals the Potential Biomarkers in Crohn’s Disease Rats Treated with Herb-Partitioned Moxibustion

Background

Long noncoding RNA (lncRNA) is receiving growing attention in Crohn’s disease (CD). However, the mechanism by which herb-partitioned moxibustion (HPM) regulates the expression and functions of lncRNAs in CD rats is still unclear. The aim of our study is to identify lncRNA-miRNA-mRNA network potential biological functions in CD.

Methods

RNA sequencing and microRNA (miRNA) sequencing were carried out to analyze lncRNA, miRNA and mRNA expression profiles among the CD rats, normal control rats, and CD rats after HPM treatment and constructed the potential related lncRNA-miRNA-mRNA competing endogenous RNA (ceRNA) networks. Then, Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis, protein–protein interaction (PPI) analysis and quantitative real-time polymerase chain reaction (qRT-PCR) were performed to explore potentially important genes in ceRNA networks.

Results

A total of 189 lncRNAs, 32 miRNAs and 463 mRNAs were determined as differentially expressed (DE) genes in CD rats compared to normal control rats, and 161 lncRNAs, 12 miRNAs and 130 mRNAs were identified as remarkably DE genes in CD rats after HPM treatment compared to CD rats. GO analysis indicated that the target genes were most enriched in cAMP and in KEGG pathway analysis the main pathways included adipocytokine, PPAR, AMPK, FoxO and PI3K-Akt signaling pathway. Finally, qRT-PCR results confirmed that lncRNA LOC102550026 sponged miRNA-34c-5p to regulate the intestinal immune inflammatory response by targeting Pck1.

Conclusion

By constructing a ceRNA network with lncRNA-miRNA-mRNA, PCR verification, and KEGG analysis, we revealed that LOC102550026/miRNA-34c-5p/Pck1 axis and adipocytokine, PPAR, AMPK, FoxO, and PI3K-Akt signaling pathways might regulate the intestinal immune-inflammatory response, and HPM may regulate the lncRNA LOC102550026/miR-34c-5p/Pck1 axis and adipocytokine, PPAR, AMPK, FoxO, and PI3K-Akt signaling pathways, thus improving intestinal inflammation in CD. These findings may be novel potential targets in CD.

A flavonoid rich standardized extract of Glycyrrhiza glabra protects intestinal epithelial barrier function and regulates the tight-junction proteins expression

BACKGROUND

Intestinal epithelial barrier dysfunction predisposes to many gastrointestinal, metabolic, and psychological disorders. A flavonoid rich extract of Glycyrrhiza glabra (FREG) has previously been reported to possess anti-inflammatory, antioxidant, and antiulcer properties.

AIM

To investigate the effect of FREG (GutGard^®) on restoring intestinal barrier function in tumor necrosis factor-alpha (TNF-α) stimulated human colonic adenocarcinoma cell monolayer (Caco-2) and 2,4,6-Trinitrobenzenesulfonic acid (TNBS) induced ulcerative colitis in rats.

METHODS

In in vitro, human intestinal Caco-2 cell monolayers were treated with TNF-α in the presence or absence of FREG and the paracellular permeability to FITC-conjugated 4-kD dextran (FD4) was measured to evaluate protection against the barrier dysfunction. In in vivo, intestinal barrier dysfunction was induced in male albino Wistar rats via intrarectal instillation of TNBS. Subsequently, the rats were treated orally with either FREG at 6.25, 12.5, and 25 mg/kg body weight, or Mesacol (250 mg/kg) for 5 days. On day 5, intestinal epithelial permeability was assessed with FD4 leakage into the serum. Also, colonic inflammation, colon morphology, histology and macroscopic score, weight to length ratio were evaluated. The activity of myeloperoxidase (MPO), TNF- α, secretory IgA levels and tight junction proteins expression were evaluated in rat's colon.

RESULTS

FREG protected the intestinal epithelial barrier integrity in human intestinal Caco-2 cells in vitro. FREG administration significantly improved the intestinal epithelial barrier function as evident from significant reduction in FD4 leakage. The colon morphology, histology score, macroscopic score, colon weight to length ratio also indicates beneficial effects of FREG on barrier function. In addition, FREG regulated the tight junction proteins, and markedly decreased TNF-α, MPO levels and significantly increased the secretory IgA levels in TNBS induced colitis rats.

CONCLUSION

The study findings support the protective action of FREG on intestinal epithelial barrier integrity indicating its potential in protecting from implications of leaky gut.

Innovations and advances in modelling and measuring pain in animals

Best practices in preclinical algesiometry (pain behaviour testing) have shifted over the past decade as a result of technological advancements, the continued dearth of translational progress and the emphasis that funding institutions and journals have placed on rigour and reproducibility. Here we describe the changing trends in research methods by analysing the methods reported in preclinical pain publications from the past 40 years, with a focus on the last 5 years. We also discuss how the status quo may be hampering translational success. This discussion is centred on four fundamental decisions that apply to every pain behaviour experiment: choice of subject (model organism), choice of assay (pain-inducing injury), laboratory environment and choice of outcome measures. Finally, we discuss how human tissues, which are increasingly accessible, can be used to validate the translatability of targets and mechanisms identified in animal pain models.

Effects of Herb-Partitioned Moxibustion on Autophagy and Immune Activity in the Colon Tissue of Rats with Crohn’s Disease

Objective

To investigate the mechanism of action of herb-partitioned moxibustion on CD from the perspective of autophagy and immunity.

Methods

The expression of microtubule-associated protein LC3II and SQSTM1/p62 in the colon tissues was detected by immunohistochemistry. Western blot was used to detect the expression of autophagic and immune-related proteins in the colon, such as LC3II, SQSTM1/p62, Beclin1, ATG16L1, NOD2, IRGM, IL-1β, IL-17, and TNF-β. mRNA levels of immune factors, such as IL-1β, IL-17, and TNF-β, and autophagy signaling molecules, such as PI3KC, AKT1, LKB1, and mTOR, were detected by RT-qPCR.

Results

Herb-partitioned moxibustion reduced the protein levels of ATG16L1, NOD2, IRGM, LC3II, and Beclin1 (P < 0.01) and both the protein and mRNA levels of IL-1β, IL-17, and TNF-β in CD rats (P < 0.01 or P < 0.05), and it also increased the expression of SQSTM1/p62 protein (P < 0.01). The modulatory effects of herb-partitioned moxibustion on ATG16L1, NOD2, IRGM, LC3II, TNF-β, and IL-17 protein and IL-1β protein and mRNA were better than those of mesalazine (P < 0.01 or P < 0.05). Herb-partitioned moxibustion also reduced colon PI3KC, AKT1, and LKB1 mRNA expressions in CD rats (P < 0.01 or P < 0.05) and increased mTOR protein expression (P < 0.05). And the modulatory effect of herb-partitioned moxibustion on AKT1 mRNA was better than that of mesalazine (P < 0.05).

Conclusion

Herb-partitioned moxibustion may inhibit excessively activated autophagy and modulate the expression of immune-related factors by regulating the LKB1-mTOR-PI3KC signal transduction networks, thereby alleviating intestinal inflammation in CD rats.

Biological Effects of Indole-3-Propionic Acid, a Gut Microbiota-Derived Metabolite, and Its Precursor Tryptophan in Mammals' Health and Disease

Actions of symbiotic gut microbiota are in dynamic balance with the host’s organism to maintain homeostasis. Many different factors have an impact on this relationship, including bacterial metabolites. Several substrates for their synthesis have been established, including tryptophan, an exogenous amino acid. Many biological processes are influenced by the action of tryptophan and its endogenous metabolites, serotonin, and melatonin. Recent research findings also provide evidence that gut bacteria-derived metabolites of tryptophan share the biological effects of their precursor. Thus, this review aims to investigate the biological actions of indole-3-propionic acid (IPA), a gut microbiota-derived metabolite of tryptophan. We searched PUBMED and Google Scholar databases to identify pre-clinical and clinical studies evaluating the impact of IPA on the health and pathophysiology of the immune, nervous, gastrointestinal and cardiovascular system in mammals. IPA exhibits a similar impact on the energetic balance and cardiovascular system to its precursor, tryptophan. Additionally, IPA has a positive impact on a cellular level, by preventing oxidative stress injury, lipoperoxidation and inhibiting synthesis of proinflammatory cytokines. Its synthesis can be diminished in the presence of different risk factors of atherosclerosis. On the other hand, protective factors, such as the introduction of a Mediterranean diet, tend to increase its plasma concentration. IPA seems to be a promising new target, linking gut health with the cardiovascular system.

Efficacy of a functional food ingredient from Ensete superbum Roxb Cheesman peel in reducing the severity of ulcerative colitis in murine model

Ulcerative colitis is a recurrent inflammatory illness of the colon with an elevated risk of developing colon cancer. The drugs presently used to treat UC cause adverse effects and are...

Anti-Inflammatory, Antioxidant, and Healing-Promoting Effects of Aloe vera Extract in the Experimental Colitis in Rats

Background. Ulcerative colitis is a worldwide chronic gastrointestinal disease characterized by variable extensions of colon mucosal inflammation. The available drugs have an incomplete response with various side effects and socioeconomic impacts. Aloe barbadensis Miller (Aloe vera) is a well-known medicinal plant with diverse pharmacological and therapeutic activities. As a result, in the current study, Aloe vera was selected to evaluate its therapeutic effects on experimental colitis in rats. Methods. This study is intended to evaluate the possible beneficial effect of Aloe vera for the treatment of experimental colitis. Trinitrobenzenesulfonic acid (TNBS) was used to induce experimental colitis in 60 of 70 Wistar rats. The rats were grouped in 7 clusters including healthy control, negative, positive control (received sulfasalazine), and test groups treated with Aloe vera extracts via oral or rectal routes. Macroscopic and histologic factors as well as the biochemical parameters were evaluated on day 7. Results. In the present study, it was found that serum levels of tumor necrosis factor-α (75 vs. 44 pg./ml), interleukin-6 (41 vs. 21 pg/ml), and nitric oxide (24 vs. 6 μm/ml) in TNBS-induced untreated colitis treatment were significantly increased as compared to healthy control. Similar patterns were also observed in malondialdehyde (76.41 vs. 236.35 μg/mg) and myeloperoxidase (4.24 vs. 29.38 U/mg) in colonic tissue. Among different treatments, rectal administration of Aloe vera extract (400 mg/kg) exhibited the best result in which serum concentration of tumor necrosis factor-α (55 pg/ml), interleukin-6 (24 pg/ml), and nitric oxide (10 μm/ml) and the levels of malondialdehyde (102.67 μg/mg), as well as myeloperoxidase (12.29 U/mg) in colon tissue, were reduced as compared to the untreated group. Also, the body weight and colon weight/length ratios were more improved in the treated group with 400 mg/kg Aloe vera extract, rectally. Conclusion. Aloe vera extract exhibited a therapeutic effect in TNBS-induced colitis, and local, rectal administration of Aloe vera extract was more effective than oral administration.

Herb-Partitioned Moxibustion Improves Crohn's Disease-Associated Intestinal Fibrosis by Suppressing the RhoA/ROCK1/MLC Pathway

Background and Aims

Intestinal fibrosis is one of the severe and common complications of Crohn's disease (CD), but the etiology and pathogenesis remain uncertain. The study intended to examine whether the effect of herb-partitioned moxibustion on rats with CD-associated intestinal fibrosis is associated with the RhoA/ROCK1/MLC pathway.

Methods

All experimental rats were randomly allocated into the normal control group (NC), model control group (MC), and herb-partitioned moxibustion group (HPM). Intestinal fibrosis was established in rats with CD by repeated rectal administrations of 2,4,6-trinitrobenzenesulfonic acid (TNBS). Herb-partitioned moxibustion was applied at the Qihai (CV6) and Tianshu (ST25) acupoints once daily for 10 days in the HPM group. In this study, histological changes were examined by hematoxylin and eosin (HE) staining; then, Masson's trichrome staining was used to assess the degree of fibrosis in each group. Experimental methods of immunohistochemistry, western blotting, and real-time PCR were applied to detect the levels of α-SMA, collagen III, RhoA, ROCK1, and p-MLC. Moreover, the double immunofluorescent staining for the colocalization of both α-SMA and ROCK1 was performed.

Results

Contrasted with the normal controls, the collagen deposition and fibrosis scores were increased in colonic tissue of model rats, and HPM decreased the collagen deposition and fibrosis scores. The protein of α-SMA and collagen III in the MC group exceeds that of the NC group; HPM decreased the expression of α-SMA and collagen III in rats with intestinal fibrosis. Similarly, the expression of RhoA, ROCK1, and p-MLC in model rats was obviously increased compared with normal controls; the expression of RhoA, ROCK1, and p-MLC was decreased after HPM. The coexpression of α-SMA and ROCK1 in rats with intestinal fibrosis was higher than normal rats.

Conclusion

HPM improves CD-associated intestinal fibrosis by suppressing the RhoA/ROCK1/MLC pathway.

Investigation of H2S Donor Treatment on Neutrophil Extracellular Traps in Experimental Colitis

Inflammatory bowel diseases (IBD) are chronic, immune-mediated disorders, which affect the gastrointestinal tract with intermittent ulceration. It is increasingly clear that neutrophil extracellular traps (NETs) seem to have a role in IBD; however, the associated pathogenesis is still not known. Furthermore, several conventional therapies are available against IBD, although these might have side effects. Our current study aimed to investigate the effects of hydrogen sulfide (H₂S) treatment on NETs formation and on the expression of inflammatory mediators in experimental rat colitis. To model IBD, 2,4,6-trinitrobenzenesulfonic acid (TNBS) was administered intracolonically (i.c.) to Wistar-Harlan male rats. Animals were treated (2 times/day) with H₂S donor Lawesson's reagent per os. Our results showed that H₂S treatment significantly decreased the extent of colonic lesions. Furthermore, the expression of members of NETs formation: peptidyl arginine deiminase 4 (PAD4), citrullinated histone H3 (citH3), myeloperoxidase (MPO) and inflammatory regulators, such as nuclear transcription factor-kappa B (NF-κB) and high-mobility group box 1 (HMGB1) were reduced in H₂S treated group compared to TNBS. Additionally, H₂S donor administration elevated the expression of ubiquitin C-terminal hydroxylase L1 (UCHL-1), a potential anti-inflammatory mediator. Taken together, our results showed that H₂S may exert anti-inflammatory effect through the inhibition of NETs formation, which suggests a new therapeutic approach against IBD.

Development and In Vivo Evaluation of Pectin Based Enteric Coated Microparticles Loaded with Mesalamine and Saccharomyces boulardii for Management of Ulcerative Colitis

Mesalamine is the first-line choice of drug for ulcerative colitis management. However, due to the nontargeted delivery of mesalamine, it shows side effects. The possible impact of mesalamine can be improved by coated microparticles in combination with S. boulardii for targeted delivery to the colon with the prevention of unwanted side effects. In this work, pectin-based mesalamine and S. boulardii loaded microparticles were prepared by dehydration technique and coated by an oil-in-oil solvent evaporation method and characterized by Scanning electron microscopy (SEM), X-ray diffraction, and zeta analysis. 2, 4, 6-Trinitrobenzenesulfonic acid was used for the induction of colitis. The anti-inflammatory effects of coated microparticles on Caco-2 cells were assessed by the determination of interleukin (IL)-8 concentration. In addition, the impact of coated microparticles on the concentration of colonic enzymes, including myeloperoxidase (MPO), lipid peroxides, and glutathione (GSH), were also evaluated. Moreover, hematological parameters, including white blood cell (WBC), erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP), were assessed. SEM data revealed that all the prepared coated microparticles had an almost spherical shape. The X-ray powder diffraction analysis of uncoated and coated microparticles showed maximum stability without any interaction. The particle size of uncoated and coated microparticles was 9.14 and 15.61 μm, respectively. The zeta potential of uncoated and coated microparticles was observed to be -26.78 and -29.36 mV, respectively. The prepared coated microparticles decreased the levels of lipid peroxides, MPO, and GSH significantly in colitis. In the Caco-2 cell culture model, the concentration of IL-8 is decreased significantly. The hematological observations confirmed that the prepared formulation showed a promising decrease in the levels of WBC, CRP, and ESR in diseased animals. Animal experiments revealed that cellulose acetate phthalate coated microparticles of mesalamine and S. boulardii significantly improved the colitis disease conditions of Wistar rats. Hence, cellulose acetate phthalate-coated microparticles of mesalamine and S. boulardii could be recommended as adjuvant therapy to achieve a synergistic effect in the management of UC. Lay summary Mesalamine is the drug of choice for the management of ulcerative colitis (UC), which inhibits mediators responsible for inflammation. We investigated the in vivo effects of cellulose acetate phthalate-coated microparticles of mesalamine with Saccharomyces boulardii (probiotic) for their efficacy against UC. Our findings evidenced that the combination of mesalamine with S. boulardii showed a synergistic effect in the 2,4,6- trinitrobenzene sulfonic acid-induced colitis model by reducing the inflammation and maintains the macroscopic features. From the observed results, it can be concluded that S. boulardii can be used to enhance the individual drug's effect in the therapeutic management of UC.

Magnetic resonance colonography assessment of acute trinitrobenzene sulfonic acid colitis in pre-pubertal rats

Pre-pubertal murine models of acute colitis are lacking. Magnetic resonance colonography (MRC) is a promising minimally invasive tool to assess colitis. We aimed to: 1/ Adapt a model of acute experimental colitis to pre-pubertal rats and determine whether MRC characteristics correlate with histological inflammation. 2/ Test this model by administering a diet supplemented in transforming growth factor β2 to reverse inflammation. Twenty-four rats were randomized at weaning to one of 3 groups: Trinitrobenzene Sulfonic Acid (TNBS) group (n = 8) fed a standard diet, that received an intra-rectal 60 mg/kg dose of TNBS-ethanol; Control group (n = 8) fed standard diet, that received a dose of intra-rectal PBS; TNBS+MODULEN group (n = 8) that received a dose of TNBS and were exclusively fed MODULEN-IBD^® after induction of colitis. One week after induction of colitis, rats were assessed by MRC, colon histopathology and inflammation markers (Interleukin 1β, Tumor necrosis factor α, Nitric Oxide Synthase 2 and Cyclooxygenase 2). TNBS induced typical features of acute colitis on histopathology and MRC (increased colon wall thickness, increased colon intensity on T2-weighted images, target sign, ulcers). Treatment with MODULEN-IBD^® did not reduce signs of colitis on MRC. Inflammatory marker expression did not differ among study groups.

Long-Term Oral Administration of Piceatannol (3,5,3',4'-Tetrahydroxystilbene) Attenuates Colon Tumor Growth Induced by Azoxymethane Plus Dextran Sulfate Sodium in C57BL/6J Mice

AIM

The effects of 3,5,3',4'-tetrahydroxystilbene (piceatannol) on azoxymethane (AOM)/dextran sulfate sodium (DSS)-induced colon cancer growth and changes in IL-1β, IL-6, tumor necrosis factor-α (cytokines), MCP-1, vascular endothelial growth factor, and PD-1 colon levels were investigated herein.

METHODS

AOM (10 mg/kg, i.p.) on day 0 induced colorectal carcinogenesis. On day 3, mice were provided with water containing 1.5% (w/v) DSS ad libitum for 3 day, and this 3-day drinking protocol was repeated twice. Piceatannol (5 and 12.5 mg/kg, twice daily) was orally administered to mice for 7-, 7-, 7-, and 6-day and then discontinued for 14-, 15-, and 16-day. Cytokines, chemokine, and PD-1 colon levels were measured by the respective ELISA kits.

RESULTS

In mice administered piceatannol (12.5 mg/kg), the tumor number, tumor area, and Ki-67-positive cell numbers decreased by 30.1%, 57.2%, and 89.1%, respectively, colon MCP-1 and PD-1 levels showed reductions of 43.8% and 70.9%, respectively, and COX-2-positive cell numbers declined by 60.2%.

CONCLUSIONS

The inhibitory effects of piceatannol on AOM/DSS-induced colon tumor growth appear to be associated with reductions in colon MCP-1 and PD-1 levels through the downregulated expression of COX-2 in the tumor microenvironment.

Metabolomics activity screening of T cell-induced colitis reveals anti-inflammatory metabolites

[Figure: see text].

Design and evaluation of IKK-activated GSK3β inhibitory peptide as an inflammation-responsive anti-colitic therapeutic

Glycogen synthase kinase-3β (GSK3β), a multi-functional kinase, is a promising therapeutic target for the treatment of inflammation. Inhibitory κB kinase (IKK)-activated GSK3β inhibitory peptide (IAGIP) was designed as an inflammation-responsive anti-colitic therapeutic. To optimize therapeutic efficiency, IAGIP was tested using two different drug delivery techniques: colon-targeted delivery and cell-permeable peptide modification. In cell-based experiments, in response to tumor necrosis factor (TNF)- and lipopolysaccharide (LPS)-mediated activation of IKK, cell-permeable IAGIP (CTP-IAGIP) inhibited GSK3β, leading to increased production of anti-inflammatory cytokine interleukin-10 (IL-10) and suppression of TNF- and LPS-induced NFκB activity. Oral gavage of CTP-IAGIP loaded in the colon-targeted capsule attenuated 2,4,6-trinitrobenzene sulfonic acid-induced rat colitis and lowered the expression levels of NFκB-regulated proteins in the inflamed colons. CTP-IAGIP further induced IL-10 production in the inflamed colonic tissues; however, the levels of IL-10 were not affected in the normal colonic tissue or colonic tissue in which inflammation had subsided. Collectively, our data suggest that IAGIP administered using the aforementioned drug delivery techniques is an orally active anti-colitic drug selectively responding to inflammation.

Therapeutic Potential of a Self-Assembling Peptide Hydrogel to Treat Colonic Injuries Associated with Inflammatory Bowel Disease

BACKGROUND AND AIMS

The Self-assembling Peptide Hydrogel [SAPH, PuraMatrix], a fully synthetic peptide solution designed to replace collagen, has recently been used to promote mucosal regeneration in iatrogenic ulcers following endoscopic submucosal dissection. Herein, we evaluated its utility in ulcer repair using a rat model of topical trinitrobenzene sulphonic acid [TNBS]-induced colonic injuries.

METHODS

Colonic injuries were generated in 7-week-old rats by injecting an ethanol solution [35%, 0.2 mL] containing 0.15 M TNBS into the colonic lumen. At 2 and 4 days post-injury, the rats were subjected to endoscopy, and SAPH [or vehicle] was topically applied to the ulcerative lesion. Time-of-flight secondary ion mass spectrometry [TOF-SIMS] was used to detect SAPH. Colonic expression of cytokines and wound healing-related factors were assessed using real-time polymerase chain reaction or immunohistochemistry.

RESULTS

SAPH treatment significantly reduced ulcer length [p = 0.0014] and area [p = 0.045], while decreasing colonic weight [p = 0.0375] and histological score [p = 0.0005] 7 days after injury. SAPH treatment also decreased colonic expression of interleukin [IL]-1α [p = 0.0233] and IL-6[p = 0.0343] and increased that of claudin-1 [p = 0.0486] and villin [p = 0.0183], and β-catenin staining [p = 0.0237]. TOF-SIMS revealed lesional retention of SAPH on day 7 post-injury. Furthermore, SAPH significantly promoted healing in in vivo mechanical intestinal wound models.

CONCLUSIONS

SAPH application effectively suppressed colonic injury, downregulated inflammatory cytokine expression, and upregulated wound healing-related factor expression in the rat model; thus, it may represent a promising therapeutic strategy for IBD-related colonic ulcers.

Protective Effect of Salvianolic Acid B in Acetic Acid-Induced Experimental Colitis in a Mouse Model

In its prominent experimental studies salvianolic acid B (Sal B) is novel because of its well-defined, common physiological effects, which include anti-inflammatory, anti-depressant, cardioprotective, DNA protective, neuroprotective and hepatoprotective activity in experimental animals. Initially, Sal B was studied for its anti-inflammatory properties, used as a remedy for a wide range of disease conditions, but its specific efficacy on inflammatory bowel disease is still unclear. The aim of this current study was to understand the therapeutic potential of Sal B in an acetic acid (AA)—triggered experimental mouse colitis model. Colitis was triggered by intrarectal injection of 5% AA, and then laboratory animals were given Sal B (10, 20 and 40 μg/kg) for seven days. The ulcerated colonic mucosa was assessed by clinical experiment, macroscopical, biological and histopathological analysis. The results showed depleted SOD, CAT, GSH levels and consequential elevated MPO and MDA levels and aberrant crypt foci and mast cells were seen in the AA-induced colonic mucosa of experimental animals. The data obtained from this study demonstrate that a dose of 40 µg/kg showed an efficacious anti-ulcer effect against AA-induced experimental colitis. Based on its antioxidant efficacy, Sal B may therefore be useful as a therapeutic approach for ulcerative colitis.

Tetrahydrocannabinol (THC) Exacerbates Inflammatory Bowel Disease in Adolescent and Adult Female Rats

Inflammatory Bowel Disease (IBD) is a life-long disorder that often begins between the ages of 15 and 30. Anecdotal reports suggest cannabinoids may be an effective treatment. This study sought to determine whether home cage wheel running is an effective method to assess IBD, and whether Tetrahydrocannabinol (THC), the primary psychoactive compound in cannabis, can restore wheel running depressed by IBD. Adolescent and adult female Sprague-Dawley rats were individually housed in a cage with a running wheel. Rats were injected with trinitrobenzene sulphonic acid (TNBS) into the rectum to induce IBD-like symptoms. One day later, both vehicle and TNBS treated rats were injected with a low dose of THC (0.32 mg/kg, s.c.) or vehicle. Administration of TNBS depressed wheel running in adolescent and adult rats. No antinociceptive effect of THC was evident when administered 1 day after TNBS. In fact, administration of THC prolonged TNBS-induced depression of wheel running for over 5 days in adolescent and adult rats. These results show that home cage wheel running is depressed by TNBS-induced IBD, making it a useful tool to evaluate the behavioral consequences of IBD, and that administration of THC, instead of producing antinociception, exacerbates TNBS-induced IBD. PERSPECTIVE: This article advances research on inflammatory bowel disease in two important ways: 1) Home cage wheel running is a new and sensitive tool to assess the behavioral consequences of IBD in adolescent and adult rats; and 2) Administration of the cannabinoid THC exacerbates the negative behavioral effects of IBD.

Mouse Models of Intestinal Fibrosis

Mouse models are essential for investigation of underlying disease mechanisms that drive intestinal fibrosis, as well as assessment of potential therapeutic approaches to either prevent or resolve fibrosis. Here we describe several common mouse models of intestinal inflammation and fibrosis, including chemically driven colitis models, a bacterially triggered colitis model, and spontaneous intestinal inflammation in genetically susceptible mouse strains. Detailed protocols are provided for dextran sodium sulfate (DSS) colitis, 2,4,6-trinitro-benzene sulfonic acid (TNBS) colitis, adherent-invasive Escherichia coli (AIEC)-triggered colitis, the interleukin-10 knockout (IL-10KO) mouse model of spontaneous colitis, and the SAMP/YitFc model of spontaneous ileocolitis.

Protective effect of sarsasapogenin in TNBS induced ulcerative colitis in rats associated with downregulation of pro-inflammatory mediators and oxidative stress

BACKGROUND

Ulcerative colitis (UC) is a chronic inflammatory bowel condition considered by oxido-nitrosative stress and the release of pro-inflammatory cytokines that affects the mucosal lining of the colon. Sarsasapogenin (SG), as an active component, has been found in many plants, and it exhibits potential protective effects, such as anti-inflammatory, antioxidant, anti-psoriasis, anti-arthritis, anti-asthma, anti-depressant and anti-cancer. However, the effects of SG on UC remain unknown.

OBJECTIVE

The purpose of this study was to investigate the effects of SG on 2, 4, 6-trinitrobenzene sulfonic acid (TNBS)-induced UC in rats.

METHOD

Thirty Wistar rats were randomized into five groups: (i) Normal control, (ii) Disease control (TNBS), (iii) Sarsasapogenin (SG) (50 µg/rat), (iv) Fluticasone (FC) (50 µg/rat), (v) Sarsasapogenin + Fluticasone (SG + FC) (25 µg/rat). UC was induced in rats by trans-rectal instillation of TNBS (10 mg/kg). SG, FC and SG + FC were administered for 11 days and on the 8th day colitis was induced. Several molecular, biochemical and histological alterations were evaluated in the colon tissue. All treatment group results were compared to the TNBS group results.

RESULT

The study results revealed that treatment of rats with SG and SG + FC combination significantly decreased the colon weight/length ratio, macroscopic inflammation score, lesions score, diarrhea score and adhesion score. Combination treatment in rats significantly reduced the production of biochemical parameters, proinflammatory cytokines, haematological parameters, serum IgE levels and restored the oxidative stress markers. SG and SG + FC treatment also considerably restored the histopathological changes induced by TNBS.

CONCLUSION

Thus, SG and SG + FC combination could alter the disease progression and could be a hopeful therapeutic target for the management of UC by reducing its dose in combination with FC to elude the long term adverse effects of FC.

Effects of olives and their constituents on the expression of ulcerative colitis: a systematic review of randomised controlled trials

Extra virgin olive oil is often associated with anti-inflammatory and antioxidant properties. Its effects on inflammatory conditions such as ulcerative colitis (UC), however, have yet to be defined. As such, we aimed to conduct a systematic review and meta-analysis of studies investigating olive-based interventions in UC. A comprehensive database search for randomised controlled trials was performed between 9 July 2018 and 16 August 2018. Studies identified from search alerts were included up to 22 June 2020. Both individuals living with UC at any disease stage and murine models of UC were included in this review. No human trials meeting the eligibility criteria were identified, while nineteen animal studies comprised 849 murine models of UC were included in this review. Pooling of the data could not be performed due to heterogeneous outcomes; however, general trends favouring olive-based interventions were identified. Milder disease expression including weight maintenance, reduced rectal bleeding and well-formed stools favouring olive-based interventions was statistically significant in 16/19 studies, with moderate-to-large effect sizes (-0·66 (95 % CI -1·56, 0·24) to -12·70 (95 % CI -16·8, -8·7)). Olive-based interventions did not prevent the development of colitis-like pathologies in any study. In conclusion, effects of olive-based interventions on murine models of UC appear promising, with milder disease outcomes favouring the intervention in most trials and effect sizes suggesting potential clinical relevance. However, the lack of published randomised controlled human trials warrants further investigation to determine if these effects would translate to individuals living with UC.

A New Rat Model of Pouchitis After Proctocolectomy and Ileal Pouch-Anal Anastomosis Using 2,4,6-Trinitrobenzene Sulfonic Acid

BACKGROUND

Pouchitis is a common complication after ileal pouch-anal anastomosis (IPAA) in patients with ulcerative colitis. However, an ideal model remains lacking. Therefore, we aimed to establish an appropriate model resembling human pouchitis.

METHODS

Sprague-Dawley rats were randomly assigned to five groups: TNBS group, DSS group, NS group (following IPAA procedure, administrated with TNBS enema, DSS orally, normal saline enema, respectively), NI group (underwent IPAA), and sham group (underwent switch abdominal surgery). General status, weight change, hematochezia, and fecal scores were recorded. Fecal microbiota were counted under a microscope and analyzed by 16S rRNA gene high-throughput sequencing. Specimens of ileal pouch and small intestine (proximal, mid, distal) were collected to evaluate myeloperoxidase and occludin expression by immunohistochemistry and mRNA expression of pro-inflammatory markers by PCR.

RESULTS

General status, hematochezia, fecal score, and increased mRNA expression of interleukin-6 and TNF-α in the TNBS group were similar to those in the DSS group, whereas the TNBS-induced model displayed a more stable weight change and more serious dysbacteriosis, not only was fecal bacterial diversity reduced, the dominant microbiota was altered. Histopathology scores of the distal small intestine in the TNBS group were lower compared with those in the DSS group (P < 0.05). A significant difference in myeloperoxidase and occludin expression in the small intestine was also detected between the TNBS and DSS groups.

CONCLUSIONS

Our model mimicked the characteristics of human pouchitis and avoided potential side effects in the small intestine, and thus could be employed for further research.

High-Density-Immune-Complex Regulatory Macrophages Promote Recovery of Experimental Colitis in Mice

Macrophages not only play a fundamental role in the pathogenesis of inflammatory bowel disease (IBD), but they also play a major role in preserving intestinal homeostasis. In this work, we evaluated the role of macrophages in IBD and investigated whether the functional reprogramming of macrophages to a very specific phenotype could decrease disease pathogenesis. Thus, macrophages were stimulated in the presence of high-density immune complexes which strongly upregulate their production of IL-10 and downregulate pro-inflammatory cytokines. The transfer of these high-density-immune-complex regulatory macrophages into mice with colitis was examined as a potential therapy proposal to control the disease. Animals subjected to colitis induction received these high-density-immune-complex regulatory macrophages, and then the Disease Activity Index (DAI), and macroscopic and microscopic lesions were measured. The treated group showed a dramatic improvement in all parameters analyzed, with no difference with the control group. The colon was macroscopically normal in appearance and size, and microscopically colon architecture was preserved. The immunofluorescence migration assay showed that these cells migrated to the inflamed intestine, being able to locally produce the cytokine IL-10, which could explain the dramatic improvement in the clinical and pathological condition of the animals. Thus, our results demonstrate that the polarization of macrophages to a high IL-10 producer profile after stimulation with high-density immune complexes was decisive in controlling experimental colitis, and that macrophages are a potential therapeutic target to be explored in the control of colitis.

Herb-partitioned moxibustion alleviates colonic inflammation in Crohn's disease rats by inhibiting hyperactivation of the NLRP3 inflammasome via regulation of the P2X7R-Pannexin-1 signaling pathway

Crohn's disease is a chronic inflammatory bowel disease and the NLRP3 inflammasome plays an important role in Crohn's disease. Previous studies have shown that Herb-partitioned moxibustion treating (at Qihai (CV 6) and Tianshu (ST 25)) prevented the excessive activation of the NLRP3 inflammasome and repaired damaged colonic mucosa in Crohn's disease. However, the mechanism by which Herb-partitioned moxibustion (at CV 6 and ST 25) regulates NLRP3 remains unclear. In this study, we treated Crohn's disease rats with herb-partitioned moxibustion (at CV 6 and ST 25) to investigate the mechanism by which Herb-partitioned moxibustion regulates the colonic NLRP3 inflammasome by observing colon length, the colon macroscopic damage indexes, and the expression of ATP, P2X7R, Pannexin-1, NF-κBp65, NLRP3, ASC, caspase-1, IL-1β and IL-18 in the colon in Crohn's disease. Here, this study shows that herb-partitioned moxibustion (at CV 6 and ST 25) can reduce colon macroscopic damage indexes and colon histopathological scores, alleviate colon shortening and block the abnormal activation of the NLRP3 inflammasome by inhibiting the ATP content and the expression of P2X7R, Pannexin-1 and NF-κBp65, thereby reducing the release of the downstream inflammatory cytokine IL-1β and ultimately suppressing colonic inflammation in Crohn's disease rats. This study for the first time identifies the mechanism by which herb-partitioned moxibustion (at CV 6 and ST 25) may inhibit the abnormal activation of the NLRP3 inflammasome by inhibiting the P2X7R-Pannexin-1 signaling pathway in Crohn's disease rats.

2,4,6-trinitrobenzenesulfonic acid-induced colitis in Rattus norgevicus: a categorization proposal

Reproducibility in animal research is crucial for its reliance and translational relevance. The 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced model of inflammatory bowel disease (IBD) is widely used but inconsistently and incompletely characterized throughout the literature. This hinders comparisons between studies and influences the low rate of translation of effective preclinical molecules. The purpose of this study was to categorize TNBS-induced colitis, based on macroscopic and microscopic scoring systems, and to identify basic routine parameters that could anticipate those categories. We retrospectively analysed male Wistar Rattus norvegicus (n=28 for the control group and n=87 for the TNBS group) and categorized TNBS-induced colitis in three phenotypes: Mild, Moderate and Severe colitis, as for human IBD. Also, we showed that the time course of food intake and fecal excretion (but not body weight, fluid intake or welfare scores) could foresee those categories. So, routine evaluation of food intake and fecal excretion may guide researchers in planning their experiments, selecting the animals with the severity of colitis that better matches their aims, or applying early humane endpoints to animals that will not be used in the experiments. In conclusion, categorizing TNBS-induced colitis enhances the reproducibility of data gathered with this experimental model and strengths its translational relevance.

Interaction between the Renin-Angiotensin System and Enteric Neurotransmission Contributes to Colonic Dysmotility in the TNBS-Induced Model of Colitis

Angiotensin II (Ang II) regulates colon contraction, acting not only directly on smooth muscle but also indirectly, interfering with myenteric neuromodulation mediated by the activation of AT₁ /AT₂ receptors. In this article, we aimed to explore which mediators and cells were involved in Ang II-mediated colonic contraction in the TNBS-induced rat model of colitis. The contractile responses to Ang II were evaluated in distinct regions of the colon of control animals or animals with colitis in the absence and presence of different antagonists/inhibitors. Endogenous levels of Ang II in the colon were assessed by ELISA and the number of AT₁/AT₂ receptors by qPCR. Ang II caused AT₁ receptor-mediated colonic contraction that was markedly decreased along the colons of TNBS-induced rats, consistent with reduced AT₁ mRNA expression. However, the effect mediated by Ang II is much more intricate, involving (in addition to smooth muscle cells and nerve terminals) ICC and EGC, which communicate by releasing ACh and NO in a complex mechanism that changes colitis, unveiling new therapeutic targets.

Dilodendron bipinnatum Radlk. extract alleviates ulcerative colitis induced by TNBS in rats by reducing inflammatory cell infiltration, TNF-α and IL-1β concentrations, IL-17 and COX-2 expressions, supporting mucus production and promotes an antioxidant effect

ETHNOPHARMACOLOGICAL RELEVANCE

Dilodendron bipinnatum (Sapindaceae) stem bark decoction and macerate were used to treat uterine inflammation, pain in general, dermatitis and bone fractures. These homemade preparations also have diuretic, stimulant, expectorants and sedative effects and are effective in treating worm infections in the Brazilian Pantanal population. Our previous research confirmed the anti-inflammatory activity of the hydroethanolic extract of inner stem bark of D. bipinnatum (HEDb).

AIM

This work aimed to investigate the efficacy of HEDb in ameliorating experimental colitis in rats and to elucidate the possible mechanisms involved in the anti-ulcerative colitis properties of HEDb in rats and Caco-2 cell line.

MATERIALS AND METHODS

The effects on cell viability, IL-8 and TNF-α in human colon adenocarcinoma (Caco-2) were determined by flow cytometer and ELISA. Wistar rats (n = 6-7) were orally gavaged with, vehicle (0.9% saline), HEDb at doses of 20, 100 or 500 mg/kg, or mesalazine at a dose of 500 mg/kg, at 48, 24 and 1 h prior to the administration of trinitrobenzene sulfonic acid via rectal administration to induce colitis. The anti-inflammatory effects of HEDb were assessed macroscopically, by myeloperoxidase (MPO) activity and for glutathione (GSH) concentration in the colon. Additionally, colonic histopathological analyses of UC severity were conducted by different staining methods (H&E, PAS and toluidine blue). Pro-inflammatory cytokines TNF-α and IL-1β were quantified in colonic tissue by ELISA and colonic expressions of COX-2 and IL-17 were analyzed by western blotting.

RESULTS

HEDb was shown to be non-cytotoxic with mean viability of 80% in Caco-2 cells. HEDb pre-treatments of 1, 5 or 20 μg/mL significantly reduced TNF-α production in Caco-2 cells by 21.8% (p < 0.05), 60.5 and 82.1% (p < 0.001) respectively following LPS treatment compared to LPS alone. However, no change in IL-8 production was observed. HEDb pre-treatment of rats subjected to TNBS significantly (p < 0.001) reduced colonic lesion score. Higher doses (100 and 500 mg/kg) caused a sharp downregulation of haemorrhagic damage, leukocyte infiltration, edema and restoration of mucus production. Moreover, mast cell degranulation was inhibited. Colonic MPO activity was reduced following all doses of HEDb, reaching 51.1% ± 1.51 (p < 0.05) with the highest dose. GSH concentration was restored by 58% and 70% following 100 and 500 mg/kg of HEDb, respectively. The oral treatment of HEDb at doses 20, 100 and 500 mg/kg decreased the concentrations of TNF-α and IL-1β at all doses in comparison to vehicle treated control. In addition, HEDb inhibited the COX-2 and IL-17 expressions with maximal effect at 500 mg/kg (60.3% and 65% respectively; p < 0.001). In all trials, the effect of HEDb at all doses being 20, 100 and 500 mg/kg was statistically comparable to mesalazine (500 mg/kg).

CONCLUSIONS

HEDb reduces colonic damage in the TNBS colitis model and relieves oxidative and inflammatory events, at least in part, by increasing mucus production, reducing leukocyte migration and reducing TNF-α (in vivo and in vitro), IL-1β, IL-17 and COX-2 expression. Therefore, HEDb requires further investigation as a candidate for treating IBD.