Effects of tumour necrosis factor-alpha synthesis inhibitors on rat trinitrobenzene sulphonic acid-induced chronic colitis

Protective effect of sucrose esters from cape gooseberry (Physalis peruviana L.) in TNBS-induced colitis

Phytotherapy is an attractive strategy to treat inflammatory bowel disease (IBD) that could be especially useful in developing countries. We previously demonstrated the intestinal anti-inflammatory effect of the total ethereal extract from the Physalis peruviana (Cape gooseberry) calyces in TNBS-induced colitis. This work investigates the therapeutic potential of Peruviose A and B, two sucrose esters that constitute the major metabolites of its calyces. The effect of the Peruvioses A and B mixture on TNBS-induced colitis was studied after 3 (preventive) and 15-days (therapy set-up) of colitis induction in rats. Colonic inflammation was assessed by measuring macroscopic/histologic damage, MPO activity, and biochemical changes. Additionally, LPS-stimulated RAW 264.7 macrophages were treated with test compounds to determine the effect on cytokine imbalance in these cells. Peruvioses mixture ameliorated TNBS-induced colitis in acute (preventive) or established (therapeutic) settings. Although 3-day treatment with compounds did not produce a potent effect, it was sufficient to significantly reduce the extent/severity of tissue damage and the microscopic disturbances. Beneficial effects in the therapy set-up were substantially higher and involved the inhibition of pro-inflammatory enzymes (iNOS, COX-2), cytokines (TNF-α, IL-1β, and IL-6), as well as epithelial regeneration with restoration of goblet cells numbers and expression of MUC-2 and TFF-3. Consistently, LPS-induced RAW 264.7 cells produced less NO, PGE2, TNF-α, IL-6, and MCP-1. These effects might be related to the inhibition of the NF-κB signaling pathway. Our results suggest that sucrose esters from P. peruviana calyces, non-edible waste from fruit production, might be useful as an alternative IBD treatment.

Therapeutic Potential of BMP7 in the Treatment of Osteoporosis Caused by the Interaction between Inflammation and Corticosteroids in Inflammatory Bowel Disease

Individuals with inflammatory bowel disease (IBD) have an increased risk of bone impairment, which is a process controlled by the RANKL/RANK/OPG system, mostly due to chronic inflammation and corticosteroid treatment. Bone morphogenic protein 7 (BMP7) has a complex role in maintaining inflammation and bone remodeling but little is known about its anti-inflammatory potential in chronic colitis. We investigated the effect of systemically administered BMP7 and corticosteroids on the severity of inflammation, macrophage differentiation, and bone regeneration in a chronic IBD model.

METHODS

Chronic colitis was induced in male Sprague Dawley rats via weekly administration of 2,4,6-trinitrobenzenesulfonic acid over 21 days following BMP7 or corticosteroid treatment for five days. The levels of serum and colon tissue inflammatory cytokines, RANKL/OPG system, as well as markers of macrophage polarization, were detected using RT-PCR, ELISA, or immunohistochemistry. Long bone and spine analyses were performed using microcomputed tomography (micro-CT).

RESULTS

The administration of BMP7 reduced the adverse effects of colitis and led to elevated OPG and RANK in the colon with a simultaneous decrease in TNF-α and an increase in IL-10 and TGF-β. Decreased expression of the M2 macrophage marker CD163 was found in the BMP7-treated rats compared with the colitis group, whereas the number of M1 marker iNOS-positive cells did not differ between the groups. As a result of the BMP7 treatment, morphometric parameters of trabecular bone increased, and increased trabecular separation noted in the colitis group did not appear.

CONCLUSIONS

We showed that BMP7 suppressed the inflammatory response in chronic colitis, mainly by shifting the cytokine balance and by triggering alterations in the RANKL/OPG system rather than through a macrophage polarization imbalance. In addition, considering the demonstrated effect of BMP7 on bone morphology and structure, it can be suggested that BMP7 plays a role in the managing of osteoporosis in chronic colitis, and thus, its therapeutic potential in the treatment of IBD should be further evaluated.

Microbiome Structure and Mucosal Morphology of Jejunum Appendix and Colon of Rats in Health and Dysbiosis

Gut microbiota contributes to human health. Plenty of studies demonstrate that antibiotics can disrupt gut ecosystem leading to dysbiosis. Little is known about the microbial variation of appendix and its up/downstream intestine after antibiotic treatment. This study aimed to investigate the microbiome and mucosal morphology of jejunum, appendix, and colon of rats in health and dysbiosis. A rodent model of antibiotic-induced dysbiosis was employed. Microscopy was used to observe mucosal morphological changes. 16S rRNA sequencing was performed for identifying bacterial taxa and microbiome structure. The appendices of dysbiosis were found enlarged and inflated with loose contents. Microscopy revealed the impairment of intestinal epithelial cells. High-throughput sequencing showed the Operational Taxonomic Units changed from 361 ± 33, 634 ± 18, 639 ± 19 in the normal jejunum, appendix, colon to 748 ± 98, 230 ± 11, 253 ± 16 in the disordered segments, respectively. In dysbiosis, Bacteroidetes translocated inversely from the colon and appendix (0.26%, 0.23%) to the jejunum (13.87% ± 0.11%); the relative abundance of all intestinal Enterococcaceae increased, while Lactobacillaceae decreased. Several bacterial clusters were found correlated to the normal appendix, whereas nonspecific clusters correlated to the disordered appendix. In conclusion, species richness and evenness reduced in the disordered appendix and colon; similar microbiome patterns were shared between the appendix and colon regardless of dysbiosis; site-specific bacteria were missing in the disordered appendix. Appendix is likely a transit region involving in upper and lower intestinal microflora modulation. The limitation of this study is all the data were derived from rats. We must be cautious about translating the microbiome results from rats to humans.

Protective effect of naringin ameliorates TNBS-induced colitis in rats via improving antioxidant status and pro-inflammatory cytokines

Aim: Ulcerative colitis (UC) is a chronic inflammatory bowel disease that disturbs the colon mucosal lining and is characterized by oxido-nitrosative stress and the release of pro-inflammatory cytokines. Naringin (NG) belongs to a group of chemicals called bioflavonoids derived from grapefruit and related citrus species. NG has been widely used as folk medicine in many countries, due to its several health benefits.Method: This study examined the effect of NG on 2,4,6 trinitrobenzene sulfonic acid (TNBS)-induced colitis in rats. Forty-two male Wistar rats were divided into seven groups like Normal Control (NC), Ethanol Control (EC), Disease Control (DC), NG 20 (20 mg/kg, p.o.), NG 40 (40 mg/kg, p.o.), NG 80 (80 mg/kg, p.o.), and Dexamethasone (DEX) (2 mg/kg, p.o.). Colitis was induced in Wistar albino rats by administering TNBS intra-rectally (in 50% ethanol). The rats were then given 14 days of NG (20, 40, and 80 mg/kg) and DEX (2 mg/kg) treatment. Several behavioral, biochemical, molecular, and histological analyses were performed.Result: The treatment of rats with NG significantly increased the body weight (p < .05, p < .01), hematological parameters like hemoglobin (p < .05, p < .01, p < .001), red blood cells (p < .01, p < .001), and platelets count (p < .01, p < .001) and decreased in spleen weight (p < .01, p < .001), colon weight (p < .01, p < .001), colon weight to length ratio (p < .05, p < .01, p < .001), macroscopic score (p < .01, p < .001), adhesion score (p < .01, p < .001), diarrhea score (p < .05, p < .001), stool consistency (p < .01, p < .001), rectal bleeding score (p < .05, p < .01, p < .001), white blood cells count (p < .01, p < .001). NG significantly (p < .01, p < .001) increased colonic superoxide, glutathione, and catalase levels and decreased malondialdehyde and myeloperoxidase levels. It also significantly (p < .01, p < .001) decreased the biochemical parameters, proinflammatory cytokines and reduced the histological damage in the colon tissue caused by TNBS.Conclusion: Our results demonstrated that NG treatment attenuated pathologic changes of TNBS-induced colitis in rats through restoring colonic damage and reducing inflammatory response in the colon tissue. Thus, NG might be considered as an effective candidate for the treatment of UC patients.

Renovation of Intestinal Barrier by Polydatin in Experimentally Induced Ulcerative Colitis: Comparative Ultrastructural Study with L-Carnosine

Ulcerative colitis (UC) is a chronic inflammatory bowel disease associated with intestinal epithelial barrier impairment. Polydatin (PD), a natural product isolated from Polygonum cuspidatum, is known to have an anti-inflammatory, antioxidant, and antiapoptotic effect. We attempted to compare the protective impact of PD pretreatment on alterations to the intestinal epithelial barrier and the colonic wall's ultrastructure accompanying ulcerative colitis to other conventional drugs in practice, primarily L-carnosine, which has not been addressed before. The rats were divided into 5 groups; 3 of them were treated with sulphasalazine (500 mg/kg), L-carnosine (30 mg/kg), and PD (45 mg/kg). All groups were administered their respective drugs 3 days before the UC was induced by acetic acid intra-rectally, and the treatment was continued until the 11th day. The disease activity index (DAI) was estimated, and a macroscopic scoring was established for the harvested colonic tissue. The tissues were extracted and processed for hematoxylin and eosin staining, caspase-3 immunohistochemical staining, electron microscopy, and biochemical analysis evaluating proinflammatory markers (IL-1β, TNF-α, and IL-6), myeloperoxidase (MPO), oxidative stress, and lipid peroxidation. Histopathological examination of colonic tissue showed that PD pretreatment effectively restored mucosal epithelial cells, intercellular tight junctions, goblet cells, and maintained the intestinal epithelial and endothelial barriers. PD suppressed MPO, proinflammatory markers, and malondialdehyde but enhanced superoxide dismutase and glutathione levels. It also hampered apoptosis, as evidenced by a reduction in caspase-3 expression. PD showed a significantly better response in preserving the intestinal epithelial barrier against acetic acid-induced colitis as compared to sulphasalazine and L-carnosine. These findings demonstrate the therapeutic role of PD for patients with UC.

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.

Linagliptin mitigates experimental inflammatory bowel disease in rats by targeting inflammatory and redox signaling

AIMS

Dipeptidyl peptidase-4 (DPP-4) has been involved in the pathogenesis of inflammatory bowel diseases (IBD), yet the underlying mechanisms remain inconclusive. The present study aimed to investigate the potential of linagliptin, a potent/selective DPP-4 inhibitor with marked anti-inflammatory actions, to attenuate trinitrobenzene sulfonic acid (TNBS)-evoked colitis in rats; an experimental model of IBD, and the implicated molecular mechanisms. This may add to the clinical utility of linagliptin for the management of patients with coexisting IBD and diabetes mellitus. Notably, no former studies have linked JAK2/STAT3, HMGB1/NF-κB, and Nrf2/HO-1 signaling in TNBS-evoked colitis.

MATERIALS AND METHODS

Western blotting and ELISA were used to determine the levels of target signals.

KEY FINDINGS

Administration of linagliptin (1.5 mg/kg; p.o.) mitigated the colitis severity via diminishing the disease activity index, colon weight/length ratio, and macroscopic scores. Linagliptin also lowered the colonic histologic scores and leukocyte invasion. Notably, linagliptin inhibited the colonic DPP-4 activity and upregulated the expression of intestinotrophic GLP-2 without incurring hypoglycemia in animals. Linagliptin curbed inflammation through the suppression of colonic IL-6, TNF-α, and myeloperoxidase and upregulation of IL-10. It also inhibited the IL-6/JAK2/STAT3 pathway via downregulating p-JAK2/JAK2 and p-STAT3/STAT3 protein expression and HMGB1/RAGE/NF-κB cascade through lowering HMGB1, RAGE, and p-NF-κB p65/NF-κB p65 protein expression. In the context of mucosal oxidative stress, linagliptin diminished lipid peroxides and augmented GSH, GPx, and total antioxidant capacity. It also activated Nrf2/HO-1 pathway via upregulating Nrf2 and HO-1 protein expression.

SIGNIFICANCE

Linagliptin shows a promise for the management of IBD via targeting IL-6/JAK2/STAT3, HMGB1/RAGE/NF-κB, and Nrf2/HO-1 pathways.

Activation of autophagy and suppression of apoptosis by dapagliflozin attenuates experimental inflammatory bowel disease in rats: Targeting AMPK/mTOR, HMGB1/RAGE and Nrf2/HO-1 pathways

Dapagliflozin, a selective sodium-glucose co-transporter 2 (SGLT2) inhibitor, has featured marked anti-inflammatory effects in murine models of myocardial infarction, renal injury, and neuroinflammation. Yet, its potential impact on the pathogenesis of inflammatory bowel diseases (IBD) has not been previously investigated. The presented study aimed to explore the prospect of dapagliflozin to mitigate 2,4,6 trinitrobenzene sulfonic acid (TNBS)-induced rat colitis model which recapitulates several features of the human IBD. The molecular mechanisms pertaining to the dynamic balance between autophagy/apoptosis and colon injury were delineated, particularly, AMPK/mTOR, HMGB1/RAGE/NF-κB and Nrf2/HO-1 pathways. The colon tissues were examined using immunoblotting, ELISA, and histopathology. Dapagliflozin (0.1, 1 and 5 mg/kg; p.o.) dose-dependently mitigated colitis severity as manifested by suppression of the disease activity scores, macroscopic damage scores, colon weight/length ratio, histopathologic perturbations, and inflammatory markers. More important, dapagliflozin enhanced colonic autophagy via upregulating Beclin 1 and downregulating p62 SQSTM1 protein expression. In this context, dapagliflozin activated the AMPK/mTOR pathway by increasing the p-AMPK/AMPK and lowering the p-mTOR/mTOR ratios, thereby, favoring autophagy. Moreover, dapagliflozin dampened the colonic apoptosis via lowering the caspase-3 activity, cleaved caspase-3 expression, and Bax/Bcl-2 ratio. Furthermore, dapagliflozin attenuated the HMGB1/RAGE/NF-κB pathway via lowering HMGB1, RAGE, and p-NF-κBp65 protein expression. Regarding oxidative stress, dapagliflozin lowered the oxidative stress markers and augmented the Nrf2/HO-1 pathway. Together, the present study reveals, for the first time, the ameliorative effect of dapagliflozin against experimental colitis via augmenting colonic autophagy and curbing apoptosis through activation of AMPK/mTOR and Nrf2/HO-1 pathways and suppression of HMGB1/RAGE/NF-κB cascade.

Hecogenin and fluticasone combination attenuates TNBS-induced ulcerative colitis in rats via downregulation of pro-inflammatory mediators and oxidative stress

OBJECTIVE

Ulcerative colitis is common types of severe, progressive, idiopathic inflammatory bowel disease that involves the mucosal lining of the large intestine. The purpose of the study is to explore the effects of hecogenin in TNBS (2, 4, 6- trinitrobenzene sulfonic acid) induced ulcerative colitis model in rats.

MATERIAL AND METHODS

Thirty Wistar rats were randomized into five groups: (i) Normal Control (NC), (ii) Disease Control (DC), (iii) Hecogenin (HG) (50 µg/rat), (iv) Fluticasone (FC) (50 µg/rat), (v) Hecogenin + Fluticasone (HG + FC) combination (25 µg/rat). Colitis was induced by trans-rectal administration of TNBS using a catheter inserted 8 cm into the rectal portion of the rat. Colitis was evaluated by an independent observer who was blinded to the treatment. All treatment group results were compared to the TNBS group results.

RESULTS

The study results revealed that treatment of rats with HG and HG + FC significantly improved the body weight and colon length whereas; decreased the spleen weight, colon weight/length ratio, macroscopic lesions score, diarrhea score and adhesion score. The drug treatment in rats substantially decreased the development of inflammatory cytokines, levels of serum immunoglobulin E, colonic nitric oxide contents and restoration of antioxidant stress markers. Histopathological colon sample study significantly reduced colonic inflammation with a substantial decrease in inflammation score.

CONCLUSION

Thus, HG and HG + FC combination could change the pathogenesis of the disease and may be a potential therapeutic target for the treatment of ulcerative colitis by a reduction in dose in conjunction with FC to prevent the persistent adverse effects associated with FC.

Huangkui Lianchang Decoction Ameliorates DSS-Induced Ulcerative Colitis in Mice by Inhibiting the NF-kappaB Signaling Pathway

BACKGROUND

The nuclear factor kappa beta (NF-κB) signaling pathway plays an important role in ulcerative colitis (UC). Huangkui Lianchang decoction (HLD) is an effective traditional Chinese medicinal compound used in the treatment of UC. HLD has good effects in the clinic, but the mechanism by which HLD acts is unclear. This study aims to reveal the exact molecular mechanism of HLD in the treatment of UC.

METHODS

Mouse ulcerative colitis was induced by dextran sulfate sodium (DSS) and treated with HLD. Intestinal damage was assessed by disease activity index (DAI), colon macroscopic lesion scores, and histological scores. Interleukin (IL)-6, tumor necrosis factor (TNF)-α, and IL-1β were detected in colon tissue using ELISA. Myeloperoxidase (MPO) and superoxide dismutase (SOD) activities in the colonic mucosa were measured. The levels of IL-6, inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX-2) in the colon were determined by real-time quantitative polymerase chain reaction (qPCR). The expression of NF-κB, IκBα, and p-IκBα in the colon was measured by Western blot.

RESULTS

After treatment with HLD, the DAI scores, macroscopic lesion scores, and histological scores decreased, and the levels of inflammatory cytokines related to the NF-κB signaling pathway, such as IL-6, TNF-α, and IL-1β, as well as those of iNOS and COX-2, were reduced; at the same time, colonic pathological damage was alleviated, and the MPO and SOD activities decreased. Western blot confirmed that HLD can inhibit the NF-κB signaling pathway in DSS-induced ulcerative colitis.

CONCLUSION

HLD can alleviate the inflammation caused by ulcerative colitis. In particular, high doses of HLD can significantly alleviate intestinal inflammation and have comparable efficacy to Mesalazine. We propose that the anti-inflammatory activity of HLD on DSS-induced colitis in mice may involve the inhibition of the NF-κB pathway.

Preventive effect of bergenin against the development of TNBS-induced acute colitis in rats is associated with inflammatory mediators inhibition and NLRP3/ASC inflammasome signaling pathways

Ulcerative colitis is an idiopathic inflammatory bowel disease characterized by intestinal inflammation; blocking this inflammatory process may be the key to the development of new naturally occurring anti-inflammatory drugs, with greater efficiency and lower side effects. The objective of this study is to explore the effects of bergenin (BG) in TNBS (2,4,6-trinitrobenzenesulfonic acid)-induced acute colitis model in rats in order to assist in the studies for the development of novel natural product therapies for inflammatory bowel disease. 48 Wistar rats were randomized into six groups: (i) Control and (ii) TNBS control; (iii) 5-ASA 100 mg/kg/day (iv) BG 12 mg/kg/day (v) BG 25 mg/kg/day and (vi) BG 50 mg/kg/day. Colitis was induced by instillation of TNBS. Colitis was evaluated by an independent observer who was blinded to the treatment. Our results revealed that bergenin decreased the macroscopic and microscopic damage signs of colitis, and reduced the degree of neutrophilic infiltration in the colon tissue; also, it was capable to down-regulate COX-2, iNOS, IkB-α, and pSTAT3 protein expression. Similarly, using a protocol for indirect ELISA quantification of cytokines, bergenin treatment reduced IL-1β, IFN-γ and IL-10 levels, and inhibited both canonical (IL-1) and non-canonical (IL-11) NLRP3/ASC inflammasome signaling pathways in TNBS-induced acute colitis. Conclusion: Our study has provided evidence that administration of bergenin reduced the damage caused by TNBS in an experimental model of acute colitis in rats, reduced levels of pro-inflammatory proteins and cytokines probably by modulation of pSTAT3 and NF-κB signaling and blocking canonical and non-canonical NLRP3/ASC inflammasome pathways.

Acupuncture points can be identified as cutaneous neurogenic inflammatory spots

Acupuncture, a traditional medical procedure practised for over 2000 years in Asia, stimulates specific but poorly defined sites called acupoints. To date, no unique anatomical acupoint structures have been found. However, noxious sensory signals from visceral organs produce hypersensitive spots on the skin (neurogenic spots), caused by cutaneous neurogenic inflammation, in the dermatome that overlaps with visceral afferent innervations. Here, we show that an acupoint is one form of neurogenic inflammation on the skin. Various studies have demonstrated that acupoints show mechanical hypersensitivity and have high electrical conductance. Stimulation of acupoints produces needling sensations caused by the activation of small diameter afferent nerve fibres and therapeutic effects on the associated visceral organs, which is likely due to the release of endogenous opioids. The present study provides experimental evidence that neurogenic spots exhibit all the characteristics of the acupoints listed above. In addition, the stimulation of neurogenic spots by electrical, mechanical, or chemical means alleviated pathological conditions in rat colitis and hypertension models via the endogenous opioid system. Our results suggest that acupoints associated with internal organs may be identical to neurogenic inflammatory spots on the skin, which are produced by activation of somatic afferents in abnormal conditions of visceral organs.

Transplantation of a bacterial consortium ameliorates trinitrobenzenesulfonic acid-induced colitis and intestinal dysbiosis in rats

AIM

To investigate the effects of a defined bacterial consortium on trinitrobenzenesulfonic acid (TNBS)-induced colitis and intestinal dysbiosis in rats.

MATERIALS & METHODS

Rats with TNBS-induced colitis were treated with ceftriaxone and/or a mixture of ten bacterial strains isolated from mouse feces for continuous 24 days. Macroscopic and histopathological parameters in colonic tissue were compared, as were myeloperoxidase enzyme activity and cytokine levels. Patterns of intestinal microbiota were assessed by PCR-denaturing gradient gel electrophoresis, the abundance of selected microbial groups was evaluated by qPCR.

RESULTS & CONCLUSION

Transplantation of the bacterial consortium showed anti-inflammatory activity in the intestines of rats with TNBS-induced colitis and contributed to the rapid re-establishment of intestinal microbial equilibrium. A defined bacterial consortium may be a viable therapeutic option for the treatment inflammatory bowel disease.

Expression of aryl hydrocarbon receptor and ATG16L1 protein in experimental oxazolone-induced colitis in rats

We studied the expression of AhR and ATG16L1 protein in experimental oxazolone-induced colitis in rats and anti-inflammatory action of recombinant antagonist of IL-1 receptors (ARIL-1) and simvastatin. The immunopositive cells were determined using an indirect immunofluorescence technique with using a monoclonal rat antibody. It has been established that development of colitis was accompanied by an increase of total number of ATG16L1-lymphocytes (by 30%, P < 0.05) in lymphoid structures of the colon. However the amount of AhR(+)-lymphocytes has not changed. At the same time has increased the concentration of ATG16L1 protein (by 4-11%, P < 0.05) in immunopositive cells. Administration of simvastatin and ARIL-1 during the development of experimental pathology was accompanied by decrease of total number of AhR(+) (by 24-38%, P < 0.05) and ATG16L1(+)-lymphocytes (by 43% - 2 fold, P < 0.05) in the colon.

Cape Gooseberry [Physalis peruviana L.] Calyces Ameliorate TNBS Acid-induced Colitis in Rats

BACKGROUND AND AIMS

Physalis peruviana [cape gooseberry] is highly appreciated for its commercial value. The Colombian ecotype is in great demand in the international market, particularly for the unique morphological characteristics of the calyx, which has extended use as a traditional herbal remedy in Colombia because of its anti-inflammatory properties. In this work, the anti-inflammatory activity of the total ethereal extract of Physalis peruviana calyces was evaluated in preventive and therapeutic protocols in a TNBS acid-induced colitis rat model.

METHODS

Colitis was induced by intrarectal administration of TNBS. An evaluation of macroscopic and histopathological parameters in colonic tissue was performed, along with the determination of myeloperoxidase enzyme activity, cytokine levels and gene expression. Additionally, effects on nitric oxide release by lipopolysaccharide [LPS]-stimulated RAW264.7 macrophages and the scavenging activity of DPPH and ABTS free radicals were determined.

RESULTS

The treatment with the Physalis peruviana extract produced a significant improvement in the colonic tissue at both macroscopic and histological levels. IL-1β and TNF-α production was reduced by the extract in both experimental approaches. The groups treated with Physalis peruviana showed a tendency to MUC2 up-regulation and down-regulation of COX-2, iNOS, NLRP3, IL-1β, IL-6 and IL-10 expression. Nitric oxide release in RAW264.7 macrophages was significantly inhibited.

CONCLUSIONS

The Physalis peruviana extract showed intestinal anti-inflammatory activity in the TNBS-induced colitis model, placing this species' calyx, a natural derivative, as a promising source of metabolites that could be used in treatment for inflammatory bowel disease.

Curcumin half analog modulates interleukin-6 and tumor necrosis factor-alpha in inflammatory bowel disease

BACKGROUND

The present study was aimed at examining the effect of dehydrozingerone (DHZ), half analogue of curcumin which is the active constituent of turmeric (Curcuma longa) in the di-nitrochlorobenzene (DNCB) induced model for inflammatory bowel disease (IBD).

MATERIALS AND METHODS

Male Wistar rats (200-220 g) were divided into four groups (n = 6). Chemical induction of IBD was done by sensitizing with 300 µL of 20 g/L of DNCB (in acetone) onto the nape of rats for 14 days followed by intra-colonic instillation of 250 µL of DNCB (0.1% DNCB in 50% alcohol) solution on day 15. Rats in Group 1 (normal control) and Group 2 (DNCB control) were treated with vehicle. Rats in Group 3 were treated with DHZ (100 mg/kg, p.o.; 8 days) and Group 4 animals were treated with sulfasalazine (SS) (100 mg/kg, p.o.; 8 days). On 24(th) day, the rats were killed, colon removed and the macroscopic, biochemical, and histopathological evaluations were performed.

RESULTS

The levels of myeloperoxidase, thiobarbituric acid reactive substrate, and nitrite increased significantly (P < 0.05) in the DNCB group whereas reduced significantly in the DHZ and SS treated groups. Serum nitrite levels were found to be insignificant between the different groups. Interleukin-6, tumor necrosis factor-alpha level was significantly high in the DNCB group.

CONCLUSION

These findings show that DHZ can be a promising molecule for the treatment of IBD.

Anti-inflammatory Effects of Flavonoids on TNBS-induced Colitis of Rats

It has been shown that the extracts including eupatilin and quercetin-3-β-D-glucuronopyranoside had mucoprotective effects on the esophagus and stomach through their antioxidant activities. This study was designed to investigate the anti-inflammatory effect of these flavonoid compounds in an animal model of inflammatory bowel disease induced by 2,4,6-trinitrobenzene sulfonic acid. Experimental colitis was induced by intracolonic administration of 2,4,6-trinitrobenzene sulfonic acid. Extracts including eupatilin or quercetin-3-β-D-glucuronopyranoside were orally administered to animals 48, 24, and 1 h prior to the induction of colitis and then again 24 h later. The animals were sacrificed 48 h after by 2,4,6-trinitrobenzene sulfonic acid treatment and the macroscopic appearance of the colonic lesions was scored in a blinded manner on a scale of 1 to 10. The inflammatory response to colitis induction was assessed by measuring myeloperoxidase activity, nitric oxide production, tumor necrosis factor-α expression, total glutathione levels, and malondialdehyde concentrations in the colon. The results indicated that extracts including eupatilin and extracts including quercetin-3-β-D-glucuronopyranoside dose-dependently improved the morphology of the lesions induced by 2,4,6-trinitrobenzene sulfonic acid and reduced the ulcer index accordingly. In addition, rats receiving extracts including eupatilin and extracts including quercetin-3-β-D-glucuronopyranoside showed significantly decreased levels of mucosal myeloperoxidase activity, nitric oxide production, tumor necrosis factor-α expression, and malondialdehyde levels, and increased total glutathione levels. Extracts including eupatilin and extracts including quercetin-3-β-D-glucuronopyranoside ameliorated the inflammatory response and colonic injury in acute colitis by decreasing oxidative stress and neutrophil activation. Extracts including eupatilin and extracts including quercetin-3-β-D-glucuronopyranoside may inhibit acute colitis.

Preventive effect of the microalga Chlamydomonas debaryana on the acute phase of experimental colitis in rats

Inflammatory bowel diseases (IBD) are characterised by chronic uncontrolled inflammation of intestinal mucosa. Diet and nutritional factors have emerged as possible interventions for IBD. Microalgae are rich sources of n-3 PUFA and derived oxylipins. Oxylipins are lipid mediators involved in the resolution of many inflammatory disorders. The aim of the present study was to investigate the effects of the oxylipin-containing biomass of the microalga Chlamydomonas debaryana and its major oxylipin constituent, (9Z,11E,13S,15Z)-13-hydroxyoctadeca-9,11,15-trienoic acid ((13S)-HOTE), on acute 2,4,6-trinitrobenzenesulfonic acid (TNBS)-induced colitis in rats. Lyophilised microalgal biomass and (13S)-HOTE were administered by oral route 48, 24 and 1 h before the induction of colitis and 24 h later, and the rats were killed after 48 h. The treatment with the lyophilised microalga and (13S)-HOTE improved body-weight loss and colon shortening, as well as attenuated the extent of colonic damage and increased mucus production. Cellular neutrophil infiltration, with the subsequent increase in myeloperoxidase levels induced by TNBS, were also reduced after the administration of the lyophilised microalga or (13S)-HOTE. The anti-inflammatory effects of these treatments were confirmed by the inhibition of colonic TNF-α production. Moreover, lyophilised microalga or (13S)-HOTE down-regulated cyclo-oxygenase-2 and inducible nitric oxide synthase expression. The present study was the first to show the prophylactic effects of a lyophilised biomass sample of the microalga C. debaryana and the oxylipin (13S)-HOTE on TNBS-induced acute colitis in rats. Our findings suggest that the microalga C. debaryana or derived oxylipins could be used as nutraceuticals in the treatment of the active phase of IBD.

5-Aminosalicylic Acid Inhibits Acute Clostridium difficile Toxin A-Induced Colitis in Rats

We tested the hypothesis that 5-aminosalicylic acid (5-ASA) inhibits toxin A-induced generation of colonic leukotriene B₄ (LTB₄) and toxin A colitis in rats. Isolated colonic segments in anesthetized rats were treated intraluminally with toxin A for 3 hours with or without 30 minutes of pretreatment with either 5-ASA or sulfapyridine and then colonic tissue levels of LTB₄ were measured and inflammation was assessed. Separately, sulfasalazine was administered to rats in their drinking water for 5 days, isolated colonic segments were then prepared, toxin A was administered, and inflammation was assessed as before. Pretreatment with 5-ASA inhibited toxin A-induced increased tissue LTB₄ concentration in the colon. Sulfasalazine and 5-ASA but not sulfapyridine significantly inhibited toxin A colitis. However, pretreatment with 5-ASA did not protect against direct TRPV1-mediated colitis caused by capsaicin. Toxin A stimulated the release of substance P (SP), and this effect was also inhibited by sulfasalazine and 5-ASA but not by sulfapyridine. Thus, toxin A stimulates colonic LTB₄ resulting in activation of TRPV1, release of SP, and colitis. Inhibition of 5-LO by 5-ASA disrupts this pathway and supports the concept that LTB₄ activation of TRPV1 plays a role in toxin A colitis.

Myroides pelagicus from the gut of Drosophila melanogaster attenuates inflammation on dextran sodium sulfate-induced colitis

BACKGROUND AND AIM

Probiotics are live microorganisms that confer a health benefit on the host when administered in adequate amounts. In the present study, the putative probiotic strain was identified from the gut of Drosophila melanogaster and assessed for its protective effect in inflammatory bowel disease.

METHODS

Active probiotics were screened from the Drosophila melanogaster gut by the selection criteria of gastric juice tolerance, hydrophobic property, antimicrobial potential, adhesion, and invasion properties. The active probiotics were identified by 16s rDNA sequencing and the effect of these active probiotics was evaluated in a Dextran sulphate sodium (DSS)-induced mice model by estimating inflammatory markers and histopathological changes.

RESULTS

Nine Gram-positive and bile salt tolerant bacterial isolates were obtained from the gut samples. The isolates PTH 2, PTH 4, and PTH 7 clearly showed significant activity in antimicrobial potential, hydrophobic (>74%) property, and intestinal juice tolerance. Among these, PTH 7 was selected for further studies due to its significant low-invasion ability and it proved capable of reducing the secretion of proinflammatory cytokines. The 16s rDNA studies revealed that PTH 7 was Myroides pelagicus. Administration of M. pelagicus to the DSS-induced colitic animals significantly suppressed myeloperoxidase, ALP, and malondialdehyde levels, and also lowered levels of proinflammatory cytokine expression. Further, the recovery from the disease by the probiotic treatment was supported by histopathological and macroscopic observation. The treated animals did not show any adverse signs in their physiology or behavior.

CONCLUSION

Myroides pelagicus successfully prohibited inflammatory markers and acted as a potent probiotic. Future studies with this stain might prove its efficacy as a drug for the management of colitis.

Telmisartan attenuates colon inflammation, oxidative perturbations and apoptosis in a rat model of experimental inflammatory bowel disease

Accumulating evidence has indicated the implication of angiotensin II in the pathogenesis of inflammatory bowel diseases (IBD) via its proinflammatory features. Telmisartan (TLM) is an angiotensin II receptor antagonist with marked anti-inflammatory and antioxidant actions that mediated its cardio-, reno- and hepatoprotective actions. However, its impact on IBD has not been previously explored. Thus, we aimed to investigate the potential alleviating effects of TLM in tri-nitrobenezene sulphonic acid (TNBS)-induced colitis in rats. Pretreatment with TLM (10 mg/kg p.o.) attenuated the severity of colitis as evidenced by decrease of disease activity index (DAI), colon weight/length ratio, macroscopic damage, histopathological findings and leukocyte migration. TLM suppressed the inflammatory response via attenuation of tumor necrosis factor-α (TNF-α), prostaglandin E₂ (PGE₂) and myeloperoxidase (MPO) activity as a marker of neutrophil infiltration besides restoration of interleukin-10 (IL-10). TLM also suppressed mRNA and protein expression of nuclear factor kappa B (NF-κB) p65 and mRNA of cyclo-oxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) proinflammatory genes with concomitant upregulation of PPAR-γ. The alleviation of TLM to colon injury was also associated with inhibition of oxidative stress as evidenced by suppression of lipid peroxides and nitric oxide (NO) besides boosting glutathione (GSH), total anti-oxidant capacity (TAC) and the activities of superoxide dismutase (SOD) and glutathione peroxidase (GPx). With respect to apoptosis, TLM downregulated the increased mRNA, protein expression and activity of caspase-3. It also suppressed the elevation of cytochrome c and Bax mRNA besides the upregulation of Bcl-2. Together, these findings highlight evidences for the beneficial effects of TLM in IBD which are mediated through modulation of colonic inflammation, oxidative stress and apoptosis.

Modulatory effects of sesamol in dinitrochlorobenzene-induced inflammatory bowel disorder in albino rats

BACKGROUND

Inflammatory bowel disease (IBD) is a chronic inflammatory condition of gastrointestinal tract of immune, genetic and environmental origin. In the present study, we examined the effect of sesamol (SES), the main anti-oxidative constituent of Sesamum indicum (sesame seed) Linn. in the dinitrochlorobenzene (DNCB)-induced model for IBD in rats.

METHODS

The groups were divided into normal control, DNCB control, SES and sulfasalazine (SS). On day 24, the rats were killed, colon removed and the macroscopic, biochemical and histopathological evaluations were performed.

RESULTS

The levels of MPO, TBARS and nitrite increased significantly (p < 0.05) in the DNCB group, whereas reduced significantly in the SES, SS treated groups. Serum nitrite levels were found to be insignificant between the different groups. IL-6 and TNF-α levels were significantly high in the DNCB group.

CONCLUSIONS

We conclude the mucosal protective effect of SES on colon due to its potent antioxidant actions. Further investigation is required in a chronic model of different rodent strain for its role involved in the cytokine pathway.

Investigation of sesamol on myeloperoxidase and colon morphology in acetic acid-induced inflammatory bowel disorder in albino rats

Background. Inflammatory bowel disease (IBD) is a chronic inflammatory disorder of gastrointestinal tract of immune, genetic, and environmental origin. In the present study, we examined the effects of sesamol (SES), which is the active constituent of sesame oil in the acetic acid (AA) induced model for IBD in rats. Methods. The groups were divided into normal control, AA control, SES, and sulfasalazine (SS). On day 7, the rats were killed, colon was removed, and the macroscopic, biochemical, and histopathological evaluations were performed. Results. The levels of MPO, TBARS, and tissue nitrite increased significantly (P < 0.05) in the AA group whereas they reduced significantly in the SES and SS treated groups. Serum nitrite levels were found to be insignificant between the different groups. Conclusions. The mucosal protective effects of sesamol in IBD are due to its potential to reduce the myeloperoxidase and nitrite content.

Anti-inflammatory effects of Retama monosperma in acute ulcerative colitis in rats

Inflammatory bowel disease (IBD), which includes ulcerative colitis and Crohn's disease, is a chronic intestinal disorder resultant from a dysfunctional epithelial, innate and adaptive immune response to intestinal microorganisms. Current IBD treatment presents limitations in both efficacy and safety that stimulated for new active drugs. Retama spp. have been traditionally used in the Mediterranean region in treatment of pain and inflammation. In this study, the anti-inflammatory and protective properties of a standardised aqueous extract from Retama monosperma (RmE) was evaluated in vivo, by intra-colonic administration of trinitrobenzene sulfonic acid (TNBS) in rats as a Crohn's disease model. The qualitative and quantitative analysis of flavonoids from RmE was performed by high-performance liquid chromatography-tandem mass spectrometry. Oral administration of RmE diminished the severity and extension of the intestinal injuries induced by TNBS. In addition, RmE increased mucus production in goblet cells in colon mucosa, decreased neutrophil infiltration and cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) overexpression. Similarly, RmE significantly reduced p38 mitogen-activated protein kinase activation, preventing the inhibitory protein IκB degradation in colonic mucosa. RmE anti-inflammatory effects seem to be related to impairment of neutrophil function and COX-2 and iNOS down-regulation possibly through p38 MAPK and nuclear transcription factor kappa B signalling pathways. These results suggest that RmE might contribute to the development of new pharmaceutical products for inflammatory bowel disease.

Anti-inflammatory intestinal activity of Arctium lappa L. (Asteraceae) in TNBS colitis model

ETHNOPHARMACOLOGICAL RELEVANCE

In Brazilian traditional medicine, Arctium lappa (Asteraceae), has been reported to relieve gastrointestinal symptoms.

AIM OF THE STUDY

In the present study, we investigated the effects of the lactone sesquiterpene onopordopicrin enriched fraction (ONP fraction) from Arctium lappa in an experimental colitis model induced by 2,4,6 trinitrobenzene sulfonic acid and performed experiments to elucidate the underlying action mechanisms involved in that effect.

MATERIALS AND METHODS

ONP fraction (25 and 50 mg/kg/day) was orally administered 48, 24 and 1 h prior to the induction of colitis and 24 h after. The inflammatory response was assessed by gross appearance, myeloperoxidase (MPO) activity, tumor necrosis factor alpha (TNF-α) levels and a histological study of the lesions. We determined cyclooxygenase (COX)-1 and -2 protein expressions by western blotting and immunohistochemistry assays.

RESULTS

TNBS group was characterized by increased colonic wall thickness, edema, diffuse inflammatory cell infiltration, increased MPO activity and TNF-α levels. On the contrary, ONP fraction (25 and 50 mg/kg) treatment significantly reduced the macroscopic inflammation scores (p<0.05 and p<0.01, respectively) and morphological alterations associated with an increase in the mucus secretion. Similarly, the degree of neutrophil infiltration and the cytokine levels were significantly ameliorated. Moreover, COX-2 expression was up regulated in TNBS-treated rats. In contrast, ONP fraction (50 mg/kg) administration reduced COX-2 overexpression.

CONCLUSIONS

We have shown that the ONP fraction obtained from Arctium lappa exert marked protective effects in acute experimental colitis, confirming and justifying, at least in part, the popular use of this plant to treat gastrointestinal diseases.

Ameliorative effects of 3,4-oxo-isopropylidene-shikimic acid on experimental colitis and their mechanisms in rats

The aim of the present study was to investigate the therapeutic effect and mechanism of 3,4-oxo-isopropylidene-shikimic acid (ISA) on 2,4,6-trinitrobenzenesulfonic acid (TNBS)-induced colitis in rats. (50, 100, 200 mg/kg) was administered for 14 days, 1 day after the induction of colitis by TNBS. The colonic injury and inflammation were assessed by macroscopic damage scores and myeloperoxidase (MPO) activity. Malondialdehyde (MDA) and nitric oxide (NO) levels, and superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities in plasma were measured with biochemical methods. Prostaglandin E2 (PGE2) level in colon was determined by radioimmunoassay. Expressions of inducible nitric oxide synthase (iNOS), cyclo-oxygenase-2 (COX-2), inhibitor kappa B-alpha (IκBα) and nuclear factor kappa B (NF-κB) p65 proteins in the colonic tissue were detected with immunohistochemistry. Enhanced colonic mucosal injury, inflammatory response and oxidative stress were observed in the animals clystered with TNBS, which was manifested as the significant increase in colon mucosal damage index, MPO activity, levels of MDA, NO and PGE2, as well as the expressions of iNOS, COX-2 and NF-κB p65 proteins in the colonic mucosa, and the significant decrease in expressions of IκBα proteins in the colonic mucosa. However, these parameters were found to be significantly ameliorated in rats treated with ISA at given doses, especially at 100 mg/kg and 200 mg/kg. Administration of ISA may have significant therapeutic effects on experimental colitis in rats, probably due to its mechanism of antioxidation, its inhibition of arachidonic acid metabolism and its modulation of the IκBα/NF-κB p65 expression.

Treatment with diammonium glycyrrhizinate down-regulates M30 expression in ulcerative colitis in rats

AIM: To assess the therapeutic effect of diammonium glycyrrhizinate (DG) on 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced ulcerative colitis in rats and to explore the underlying mechanisms by detecting the expression of M30 and Fas/FasL.

METHODS: Thirty Wistar rats were equally randomized into a normal control group, a model group and a DG group. Ulcerative colitis was induced in the DG group and model group with TNBS by enema. After ten days, all rats were killed. Disease activity index (DAI), colon macroscopic damage score (CMDS) and histological damage score were calculated, and the expression of M30 and Fas/FasL in the colonic mucosa was detected by immunohistochemistry.

RESULTS: Compared to normal controls, the DAI, CMDS and histological damage score significantly increased in model rats (7.06 ± 0.80 vs 0.32 ± 0.14; 6.03 ± 0.61 vs 0.19 ± 0.16; 5.84 ± 0.53 vs 0.22 ± 0.11, P < 0.01). Compared to the model group, the above parameters were significantly improved in the DG group (3.33 ± 0.27 vs 7.06 ± 0.80; 3.29 ± 0.36 vs 6.03 ± 0.61; 2.98 ± 0.24 vs 5.84 ± 0.53, P < 0.05). Compared to the normal control group, the expression of M30 and Fas/FasL was up-regulated in the model group and DG group (5.76 ± 0.66 vs 0.42 ± 0.18; 26.62 ± 4.20 vs 10.81 ± 2.20; 17.11 ± 3.12 vs 6.02 ± 1.02, P < 0.01). Compared to the model group, the expression of M30 and Fas/FasL was remarkably decreased in the DG group (2.24 ± 0.48 vs 5.76 ± 0.66; 17.23 ± 3.20 vs 26.62 ± 4.20; 11.02 ± 2.12 vs 17.11 ± 3.12, P < 0.05).

CONCLUSION: Treatment with DG could reduce inflammatory injury in rats with experimental ulcerative colitis possibly by reducing the expression Fas/FasL and inhibiting apoptosis of cells in the colonic mucosa.

VSL#3 probiotics exerts the anti-inflammatory activity via PI3k/Akt and NF-κB pathway in rat model of DSS-induced colitis

VSL#3 probiotics can be effective on induction and maintenance of the remission of clinical ulcerative colitis. However, the mechanisms are not fully understood. The aim of this study was to examine the effects of VSL#3 probiotics on dextran sulfate sodium (DSS)-induced colitis in rats. Acute colitis was induced by administration of DSS 3.5 % for 7 days in rats. Rats in two groups were treated with either 15 mg VSL#3 or placebo via gastric tube once daily after induction of colitis; rats in other two groups were treated with either the wortmannin (1 mg/kg) via intraperitoneal injection or the wortmannin + VSL#3 after induction of colitis. Anti-inflammatory activity was assessed by myeloperoxidase (MPO) activity. Expression of inflammatory related mediators (iNOS, COX-2, NF-κB, Akt, and p-Akt) and cytokines (TNF-α, IL-6, and IL-10) in colonic tissue were assessed. TNF-α, IL-6, and IL-10 serum levels were also measured. Our results demonstrated that VSL#3 and wortmannin have anti-inflammatory properties by the reduced disease activity index and MPO activity. In addition, administration of VSL#3 and wortmannin for 7 days resulted in a decrease of iNOS, COX-2, NF-κB, TNF-α, IL-6, and p-Akt and an increase of IL-10 expression in colonic tissue. At the same time, administration of VSL#3 and wortmannin resulted in a decrease of TNF-α and IL-6 and an increase of IL-10 serum levels. VSL#3 probiotics therapy exerts the anti-inflammatory activity in rat model of DSS-induced colitis by inhibiting PI3K/Akt and NF-κB pathway.

Protective effects of 3,4-oxo-isopropylidene-shikimic acid on experimental colitis induced by trinitrobenzenesulfonic acid in rats

BACKGROUND

3,4-Oxo-isopropylidene-shikimic acid (ISA) is a derivative of shikimic acid (SA). SA is extracted from Illicium verum Hook.fil., which has been used in traditional Chinese medicine and used for treating vomiting, stomach aches, insomnia, skin inflammation, and rheumatic pain.

AIMS

To investigate the effects and the protective mechanism of 3,4-oxo-isopropylidene-shikimic acid on experimental colitis model induced by 2,4,6-trinitrobenzenesulfonic acid (TNBS) in rats.

METHODS

Colitis in rats was induced by colonic administration with TNBS. ISA (50, 100, and 200 mg/kg) was administered for 12 days to experimental colitis rats. The inflammatory degree was assessed by macroscopic damage score, colon weight/length ratios (mg/cm), and myeloperoxidase (MPO) activity. Malondialdehyde (MDA), glutathione (GSH), and nitric oxide (NO) levels, and superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), inducible nitric oxide synthase (iNOS) activities were measured with biochemical methods.

RESULTS

ISA significantly ameliorated macroscopic damage, reduced colon weight/length ratios and the activity of MPO, depressed MDA and NO levels and iNOS activity, and enhanced GSH level, and GSH-Px and SOD activities in the colon tissues of experimental colitis in a dose-dependent manner. Moreover, the effect of ISA (200 mg/kg) was as effective as sulfasalazine (500 mg/kg).

CONCLUSIONS

The findings of this study demonstrate the protective effect of ISA on experimental colitis, probably due to an antioxidant action.

Dietary supplementation of an ellagic acid-enriched pomegranate extract attenuates chronic colonic inflammation in rats

Dietary polyphenols present in Punica granatum (pomegranate), such as ellagitannins and ellagic acid (EA) have shown to exert anti-inflammatory and antioxidant properties. This study was designed to evaluate the effects of a dietary EA-enriched pomegranate extract (PE) in a murine chronic model of Cronh's disease (CD). Colonic injury was induced by intracolonic instillation of trinitrobenzensulfonic acid (TNBS). Rats were fed with different diets during 30 days before TNBS instillation and 2 weeks before killing: (i) standard, (ii) PE 250 mg/kg/day, (iii) PE 500 mg/kg/day, (iv) EA 10 mg/kg/day and (v) EA 10 mg/kg/day enriched-PE 250 mg/kg/day. Inflammation response was assessed by histology and MPO activity and TNF-α production. Besides, colonic expressions of iNOS, COX-2, p38, JNK, pERK1/2 MAPKs, IKBα and nuclear p65 NF-κB were studied by western blotting. MPO activity and the TNF-α levels were significantly reduced in dietary fed rats when compared with TNBS group. Similarly, PE and an EA-enriched PE diets drastically decreased COX-2 and iNOS overexpression, reduced MAPKs phosporylation and prevented the nuclear NF-κB translocation. Dietary supplementation of EA contributes in the beneficial effect of PE in this experimental colitis model and may be a novel therapeutic strategy to manage inflammatory bowel disease (IBD).

Antagonism of protease-activated receptor 2 protects against experimental colitis

Many trypsin-like serine proteases such as β-tryptase are involved in the pathogenesis of colitis and inflammatory bowel diseases. Inhibitors of individual proteases show limited efficacy in treating such conditions, but also probably disrupt digestive and defensive functions of proteases. Here, we investigate whether masking their common target, protease-activated receptor 2 (PAR2), is an effective therapeutic strategy for treating acute and chronic experimental colitis in rats. A novel PAR2 antagonist (5-isoxazoyl-Cha-Ile-spiro[indene-1,4'-piperidine]; GB88) was evaluated for the blockade of intracellular calcium release in colonocytes and anti-inflammatory activity in acute (PAR2 agonist-induced) versus chronic [2,4,6-trinitrobenzenesulfonic acid (TNBS)-induced] models of colitis in Wistar rats. Disease progression (disease activity index, weight loss, and mortality) and postmortem colonic histopathology (inflammation, bowel wall thickness, and myeloperoxidase) were measured. PAR2 and tryptase colocalization were investigated by using immunohistochemistry. GB88 was a more potent antagonist of PAR2 activation in colonocytes than another reported compound, N¹-3-methylbutyryl-N⁴-6-aminohexanoyl-piperazine (ENMD-1068) (IC₅₀ 8 μM versus 5 mM). Acute colonic inflammation induced in rats by the PAR2 agonist SLIGRL-NH₂ was inhibited by oral administration of GB88 (10 mg/kg) with markedly reduced edema, mucin depletion, PAR2 receptor internalization, and mastocytosis. Chronic TNBS-induced colitis in rats was ameliorated by GB88 (10 mg/kg/day p.o.), which reduced mortality and pathology (including colon obstruction, ulceration, wall thickness, and myeloperoxidase release) more effectively than the clinically used drug sulfasalazine (100 mg/kg/day p.o.). These disease-modifying properties for the PAR2 antagonist in both acute and chronic experimental colitis strongly support a pathogenic role for PAR2 and PAR2-activating proteases and therapeutic potential for PAR2 antagonism in inflammatory diseases of the colon.

The protective effect of the recombinant 53-kDa protein of Trichinella spiralis on experimental colitis in mice

BACKGROUND

Helminth infection has been proven to reduce the severity of experimental inflammatory bowel disease (IBD). The excretory-secretory proteins of helminths play an important role in the process of immunomodulation.

AIMS

In the present study, we aimed to investigate the protective potential of recombinant Trichinella spiralis (TS) 53-kDa protein (rTsP53), a component of excretory-secretory proteins, on experimental colitis in mice.

METHODS

BALB/c mice were treated subcutaneously with 50 μg rTsP53 three times at an interval of 5 days. Colitis was induced by intrarectal administration of 5 mg trinitrobenzene sulfonic acid (TNBS). Disease activities and macroscopic and microscopic scores were evaluated. To determine immune response provoked by rTsP53, we measured specific IgG1 and IgG2a values against rTsP53 in sera of mice. We also detected cytokine profiles as well as the markers of alternatively activated macrophages (M2) in mice.

RESULTS

RTsP53 ameliorated significantly the disease activity index (DAI) as well as the macroscopic and microscopic scores. IgG1 but not IgG2a was the predominant specific antibody detected in the sera of immunized mice, indicating the potential of stimulating T-helper (Th) 2 bias response by rTsP3. Pre-treatment with rTsP53 decreased serum Th1 cytokines (TNF-a, IFN-γ) and elevated serum levels of serum Th2 cytokines (IL-4, IL-13); it also decreased colonic Th1 cytokines (TNF-α, IL-6) and colonic regulatory cytokines (IL-10, TGF-β1). RTsP53 increased colonic M2 markers, arginase-1 (Arg-1), and found in inflammatory zone 1 (FIZZ1), compared to mice without rTsP53 pretreatment.

CONCLUSIONS

RTsP53 is a potential protective agent for IBD.

Iridoid glycosides fraction of Folium syringae leaves modulates NF-κB signal pathway and intestinal epithelial cells apoptosis in experimental colitis

BACKGROUND AND AIMS

Iridoid glycosides (IG), the major active fraction of F. syringae leaves has been demonstrated to have strong anti-inflammatory properties to ulcerative colitis (UC) in our previous study. The aim of this study was to investigate whether IG modulates the inflammatory response in experimental colitis at the level of NF-κB signal pathway and epithelial cell apoptosis.

METHODS

UC in rats was induced by administration with dextran sulfate sodium (DSS) in drinking water. The inflammatory damage was assessed by disease activity index (DAI), macroscopic findings, histology and myeloperoxidase (MPO) activity. The effect of IG on pro-inflammatory cytokines TNF-α, IL-8, COX-2 and regulatory peptide TGF-β1 was measured. Epithelial cell apoptosis and the protein and mRNA expressions of Fas/FasL, Bcl-2/Bax, caspase-3, NF-κB p65, IκBα, p-IκBα and IKKβ were detected by TUNEL method, immunohistochemistry, Western blotting and real-time quantitative PCR, respectively.

RESULTS

IG significantly ameliorated macroscopic damage and histological changes, reduced the activity of MPO, and strongly inhibited epithelial cell apoptosis. Moreover, IG markedly depressed TNF-α, IL-8, COX-2 and TGF-β1 levels in the colon tissues in a dose-dependent manner. Furthermore, IG significantly blocked of NF-κB signaling by inhibiting IκBα phosphorylation/degradation and IKKβ activity, down-regulated the protein and mRNA expressions of Fas/FasL, Bax and caspase-3, and activated Bcl-2 in intestinal epithelial cells.

CONCLUSIONS

These results demonstrated for the first time that IG possessed marked protective effects on experimental colitis through inhibition of epithelial cell apoptosis and blockade of NF-κB signal pathway.

Protective effect of ellagic acid, a natural polyphenolic compound, in a murine model of Crohn's disease

Current epidemiological and experimental studies support a beneficial role of dietary polyphenols in several gastrointestinal diseases, including inflammatory bowel disease. The aim of this study was to gain a better understanding of the effects of a naturally occurring polyphenol, ellagic acid, present in some fruits such as pomegranate, raspberries and nuts among others, in an experimental murine model of Crohn's disease by intra-colonic administration of TNBS in rats. Analysis of the lesions were carried out by macroscopic and histological technics. Inflammation response was assessed by histology and myeloperoxidase activity. iNOS and COX-2 are upregulated by MAPKs and NF-κB nuclear transcription factor in intestinal epithelial cells thus, we determined the expression of iNOS, COX-2 and the involvement of the p38, JNK, ERK1/2 MAPKs and NF-κB signalling in the protective effect of EA by western blotting. Oral administration of EA (10-20 mg/kg) diminished the severity and extension of the intestinal injuries induced by TNBS although there was no observed a significant dose-response. In addition, EA increased mucus production in goblet cells in colon mucosa, decreased neutrophil infiltration and pro-inflammatory proteins COX-2 and iNOS overexpression. Also EA was capable of reducing the activation of p38, JNK and ERK1/2 MAPKs, preventing the inhibitory protein IκB-degradation and inducing an inhibition of the nuclear translocation level of p65 in colonic mucosa. In conclusion, EA reduces the damage in a rat model of Crohn's disease, alleviates the oxidative events and returns pro-inflammatory proteins expression to basal levels probably through MAPKs and NF-κB signalling pathways.

Proanthocyanidins from grape seeds modulates the nuclear factor-kappa B signal transduction pathways in rats with TNBS-induced recurrent ulcerative colitis

The aim of this study was to elucidate the molecular mechanisms involved in the therapeutic effects of proanthocyanidins from grape seeds (GSPE) on recurrent ulcerative colitis (UC) in rats. GSPE in doses of 100, 200, and 400mg/kg were intragastrically administered per day for 7 days after recurrent colitis was twice-induced by TNBS. The levels of GSH, as well as the activity of GSH-Px and SOD in colon tissues were measured by biochemical methods. The expression levels of tumor necrosis factor-α (TNF-α) and the nuclear translocation levels of nuclear factor-kappa B (NF-κB) in the colon tissues were measured by enzyme-linked immunosorbent assay methods. Western blotting analysis was used to determine the protein expression levels of inhibitory kappa B-alpha (IκBα), inhibitor kappa B kinase (IKKα/β), phosphorylated IκBα and phosphorylated IKKα/β. GSPE treatment was associated with a remarkable increased the activity of GSH-Px and SOD with GSH levels in TNBS-induced recurrent colitis rats as compared to the model group. GSPE also significantly reduced the expression levels of TNF-α, p-IKKα/β, p-IκBα and the translocation of NF-κB in the colon mucosa. GSPE exerted a protective effect on recurrent colitis in rats by modifying the inflammatory response and promoting damaged tissue repair to improve colonic oxidative stress. Moreover, GSPE inhibited the TNBS-induced inflammatory of recurrent colitis though blocking NF-κB signaling pathways.

Anti-inflammatory effects of iridoid glycosides fraction of Folium syringae leaves on TNBS-induced colitis in rats

AIM OF THE STUDY

To investigate the effects and the protective mechanism of iridoid glycosides (IG) enriched from Folium syringae leaves on ulcerative colitis (UC) model induced by 2,4,6-trinitrobenzenesulfonic acid (TNBS) in rats.

MATERIALS AND METHODS

UC in rats was induced by colonic administration with TNBS. IG (80, 160 and 240 mg/kg) was administered for 2 weeks to experimental colitis rats. The inflammatory degree was assessed by macroscopic score, histology and myeloperoxidase (MPO) activity. Nitric oxide (NO) and malondialdehyde (MDA) levels were measured with biochemical methods. The protein expressions of nuclear factor-kappaBp65 (NF-κBp65) and mRNA expressions of pro-inflammatory cytokines, such as tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and NF-κBp65, were determined by immunohistochemistry and real-time quantitative PCR, respectively.

RESULTS

IG significantly ameliorated macroscopic damage and histological changes, reduced the activity of MPO, depressed MDA and NO levels and effectively inhibited the protein and mRNA expressions of NF-κBp65, TNF-α and IL-6 in the colon tissues of experimental colitis in a dose-dependent manner. Moreover, the effects of IG (160 mg/kg and 240 mg/kg) were superior to salicylazosulfapyridine (150 mg/kg).

CONCLUSION

We demonstrated for the first time that IG possessed marked protective effects on experimental colitis through its antioxidation and inhibiting inflammatory mediators by down-regulation of the expressions of NF-κBp65.

Anti-inflammatory intestinal activity of Abarema cochliacarpos (Gomes) Barneby & Grimes in TNBS colitis model

AIM OF THE STUDY

To assess the anti-inflammatory effect of butanolic fraction of methanolic extract from bark of Abarema cochliacarpos in acute ulcerative colitis model induced by intracolonic administration of trinitrobenzene sulfonic acid (TNBS) in Wistar rats.

MATERIALS AND METHODS

Abarema cochliacarpos (100 and 150mg/kg/day) was administered by gavage 48, 24 and 1h prior to the induction of colitis with 10mg/kg of TNBS and, 24h later.

RESULTS

Phytochemical studies by mass spectrometry (MS) and nuclear magnetic resonance spectroscopy (NMR) revealed that catechins were a major component into condensate class of tannins. Treatment with Abarema cochliacarpos decreased significantly macroscopic damage as compared with TNBS (p<0.05). Histological analysis showed that both doses of the extract improved the microscopic structure and preserved some areas of the colonic mucosa structure. In addition, myeloperoxidase activity (MPO), as a marker of neutrophil infiltration, was decreased in a dose-dependent way (p<0.01 and p<0.001 respectively), TNF-alpha level was also diminished with the highest dose of the extract (p<0.001) and, IL-10 level obtained no significant results. In order to elucidate some of the mechanisms, expression of inducible inflammatory enzymes, such as cyclooxygenase (COX)-2 and nitric oxide synthase (iNOS), were studied showing a significant reduction. Finally, the involvement of c-Jun N-terminal kinase (JNK) signalling demonstrated a reduction in the JNK activation with the highest dose (p<0.05 vs TNBS).

CONCLUSIONS

We have shown for the first time that the extracts obtained from Abarema cochliacarpos bark possess active substances, which exert marked protective effects in acute experimental colitis, confirming and justifying, at least in part, the popular use of this plant to treat gastrointestinal diseases.

Therapeutic effects of rectal administration of muscovite on experimental colitis in rats

BACKGROUND AND AIMS

The aim of this study was to investigate whether rectal administration of muscovite can ameliorate colonic inflammation in a rat model of experimental colitis, and its possible mechanism.

METHODS

Female Sprague-Dawley (SD) rats with trinitrobenzene sulfonic acid (TNBS)-induced colitis were treated with rectal administration of muscovite or 5-aminosalicylic acid (5-ASA) daily for 14 days. The changes in body weight, macroscopic damage and histologic scores were subsequently evaluated. Gene expression of tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta), mucin2 (MUC2) and trefoil factor 3 (TFF3) in the colonic tissues was assessed by semiquantitative reverse transcription polymerase chain reaction (RT-PCR) while protein levels of TNF-alpha and IL-1beta were detected by ELISA. Mucin2 expression in colonic mucosa was detected by immunohistochemistry. The capacity of muscovite to adsorb cytokines in vitro was determined by the changes in the amount of TNF-alpha, IL-1beta secreted by lipopolysaccharide (LPS)-stimulated THP-1 cells and IL-8 secreted by LPS-stimulated HT-29 cells.

RESULTS

Rectal administration of muscovite improved the loss of body weight, macroscopic and histologic scores of TNBS-induced colitis in a dose-dependent manner. Trinitrobenzene sulfonic acid-induced expression of TNF-alpha and IL-1beta was reduced by muscovite and 5-ASA treatment. Reduction of MUC2 expression in colitis rats was reversed by muscovite and 5-ASA treatment. However, the expression of TFF3 mRNA in colonic mucosa was not affected. In addition, we found muscovite inhibited the expression of TNF-alpha, IL-1beta secreted by THP-1 and IL-8 secreted by HT-29 cells in a dose-dependent manner.

CONCLUSIONS

Our study demonstrated for the first time that rectal administration of muscovite can ameliorate colonic inflammation of TNBS-induced colitis. Further confirmatory studies are needed to prove that muscovite might be a potential therapeutic agent for the treatment of ulcerative colitis.

Acute and chronic responses associated with adrenomedullin administration in experimental colitis

Adrenomedullin (AM) is a 52 amino acid peptide and member of the calcitonin gene-related peptide (CGRP) super family. Given that AM has emerged as a potential immuno-regulatory and anti-inflammatory agent in various experimental models, this study has deepened into its possible therapeutic effect in intestinal inflammation analyzing the responses in both acute and chronic (14 and 21 days) phases of TNBS-induced colitis in rats. In the acute model, AM treatment reduced the incidence of diarrhea and the severity of colonic damage, and improved the survival rate at the three doses assayed (50, 100, and 200ng/kg animal). AM administration was able to reduce the early production of TNF-alpha and collaborated to maintaining basal levels of IFN-gamma and IL-10. In the chronic studies the peptide attenuated the extent of the damage with lesser incidence of weight loss and diarrhea (50 and 100ng/kg animal). Cellular neutrophil infiltration, with the subsequent increase in myeloperoxidase (MPO) levels caused by TNBS, was reduced after chronic AM administration. The peptide played a role in the evolution of Th1/Th2 cytokines balance and chronic disease recuperation: levels of proinflammatory TNF-alpha and IFN-gamma decreased and anti-inflammatory IL-10 increased significantly. Cyclooxygenase-2 (COX-2) and nitric oxide synthase (iNOS) protein expression were not modified by AM administration, although a reduction of nitric oxide (NO) production could be detected in the chronic model. These results support a role of AM as an anti-inflammatory factor with beneficial effects in intestinal inflammatory colitis.

The effects of caffeic acid phenethyl ester (CAPE) on TNBS-induced colitis in ovariectomized rats

AIM

The aim of this investigation was to examine the effects of caffeic acid phenethyl ester (CAPE) on the development of colitis and antioxidant parameters in bilateral ovariectomized rats subjected to trinitrobenzene sulfonic acid (TNBS)-induced colitis.

MATERIALS AND METHODS

Twenty-one Wistar Albino ovariectomized female rats were divided into four subgroups (n = 5 or 6) (colitis control, vehicle control, CAPE 10 and 30 mg/kg, respectively). Colitis was induced using an enema of TNBS and ethanol, following which CAPE was administrated for 3 days to induce colitis and effect of CAPE was subsequently evaluated.

RESULTS

Based on microscopic damage scores, there was no difference between rats of the TNBS-colitis and the vehicle-treated groups, whereas treatment with CAPE 10 and 30 mg/kg, respectively, caused a significant reduction in colon injury compared to that observed in rats of the TNBS-colitis and vehicle-treated groups. The histologies of both treatment groups were not significantly different. In terms of the biochemical analyses, myeloperoxidase levels in rats from the CAPE 10 and 30 mg/kg groups were significantly different from that of the colitis control rats; however, the levels of malondialdehyde (MDA), catalase and reduced glutathione (GSH) were only significantly different from the levels found colitis control rats in rats administered 10 mg/kg. The levels of MDA, GSH and SOD in rats given CAPE were also significantly different from those of rats in the vehicle control group. These results were consistent with histological findings.

CONCLUSION

CAPE may have a positive effect on the inflammatory bowel disease treatment process and could, therefore, be used as an adjunct therapy in colitis. These effects of CAPE may occur through antiinflammatory and antioxidant mechanisms.

Ameliorative effects of bombesin and neurotensin on trinitrobenzene sulphonic acid-induced colitis, oxidative damage and apoptosis in rats

AIM: To investigate the effects of bombesin (BBS) and neurotensin (NTS) on apoptosis and colitis in an ulcerative colitis model.

METHODS: In this study, a total of 50 rats were divided equally into 5 groups. In the control group, no colitis induction or drug administration was performed. Colitis was induced in all other groups. Following the induction of colitis, BBS, NTS or both were applied to three groups of rats. The remaining group (colitis group) received no treatment. On the 11th d after induction of colitis and drug treatment, blood samples were collected for TNF-α and IL-6 level studies. Malondialdehyde (MDA), carbonyl, myeloperoxidase (MPO) and caspase-3 activities, as well as histopathological findings, evaluated in colonic tissues.

RESULTS: According to the macroscopic and microscopic findings, the study groups treated with BBS, NTS and BBS + NTS showed significantly lower damage and inflammation compared with the colitis group (macroscopic score, 2.1 ± 0.87, 3.7 ± 0.94 and 2.1 ± 0.87 vs 7.3 ± 0.94; microscopic score, 2.0 ± 0.66, 3.3 ± 0.82 and 1.8 ± 0.63 vs 5.2 ± 0.78, P < 0.01). TNF-α and IL-6 levels were increased significantly in all groups compared with the control group. These increases were significantly smaller in the BBS, NTS and BBS + NTS groups compared with the colitis group (TNF-α levels, 169.69 ± 53.56, 245.86 ± 64.85 and 175.54 ± 42.19 vs 556.44 ± 49.82; IL-6 levels, 443.30 ± 53.99, 612.80 ± 70.39 and 396.80 ± 78.43 vs 1505.90 ± 222.23, P < 0.05). The colonic MPO and MDA levels were significantly lower in control, BBS, NTS and BBS + NTS groups than in the colitis group (MPO levels, 24.36 ± 8.10, 40.51 ± 8.67 and 25.83 ± 6.43 vs 161.47 ± 38.24; MDA levels, 4.70 ± 1.41, 6.55 ± 1.12 and 4.51 ± 0.54 vs 15.60 ± 1.88, P < 0.05). Carbonyl content and caspase-3 levels were higher in the colitis and NTS groups than in control, BBS and BBS + NTS groups (carbonyl levels, 553.99 ± 59.58 and 336.26 ± 35.72 vs 209.76 ± 30.92, 219.76 ± 25.77 and 220.34 ± 36.95; caspase-3 levels, 451.70 ± 68.27 and 216.20 ± 28.17 vs 28.60 ± 6.46, 170.50 ± 32.37 and 166.50 ± 30.95, P < 0.05).

CONCLUSION: The results of this study suggest BBS and NTS, through their anti-inflammatory actions, support the maintenance of colonic integrity and merit consideration as potential agents for ameliorating colonic inflammation.

PARP inhibition reduces acute colonic inflammation in rats

Poly(ADP-ribose) polymerases (PARP) comprise a family of enzymes which catalyse poly(ADP-ribosyl)ation of DNA-binding proteins. Multiple researches indicate the importance of PARP in promoting cell recruitment and thereby inducing organ injury in various forms of inflammation, such as colitis. We have evaluated the effects of two PARP inhibitors, nicotinamide and 1,5-dihydroxyisoquinoline, in acute colitis induced by trinitrobenzensulfonic acid (TNBS) in rats. Nicotinamide (20-40 mg/kg) and 1,5-dihydroxyisoquinoline (4-8 mg/kg) were administered 48, 24 and 1 h prior to the induction of colitis as well as 24 h later. 48 h after colitis induction the lesions were blindly scored and quantified as ulcer index. Histological study and colonic inflammation were assessed by gross appearance and myeloperoxidase (MPO) activity. Prostaglandin E2 (PGE2) synthesis and, cyclooxygenase-1 and cyclooxygenase-2 expressions by Western blotting and immunohistochemistry were also performed. Inflammation following TNBS induction was characterized by increased colonic wall thickness, oedema, diffuse inflammatory cells infiltration in the mucosa and necrosis. Furthermore, increased MPO activity, cyclooxygenase-2 expression and PGE2 synthesis were significantly augmented after TNBS instillation. On the contrary, treatment with 1,5-dihydroxyisoquinoline significantly reduced the degree of colon injury and also caused a substantial reduction in the rise in MPO activity, in the increase of staining for cyclooxygenase-2, as well as in the up-regulation of PGE2 caused by TNBS in the colon. Although nicotinamide significantly did not reduce macroscopic damage, it decreased both MPO activity and PGE2 colonic levels. In conclusion, we demonstrated that PARP inhibition can exert beneficial effects in experimental colitis and may, therefore, be useful in the treatment of ulcerative colitis.