Oral administration of dextran sodium sulphate induces a caecum‐localized colitis in rabbits

Trichuris suis ova (TSO) have shown promising results in the treatment of inflammatory bowel disease (IBD) but the mechanisms which underlies this therapeutic effect cannot be studied in mice and rats as T. suis fails to colonize the rodent intestine, whilst hatching in humans and rabbits. As a suitable rabbit IBD model is currently not available, we developed a rabbit colitis model by administration of dextran sodium sulphate (DSS). White Himalayan rabbits (n = 12) received 0.1% DSS in the daily water supply for five days. Clinical symptoms were monitored daily, and rabbits were sacrificed at different time points. A genomewide expression analysis was performed with RNA isolated from caecal lamina propria mononuclear cells (LPMC) and intestinal epithelial cells (IEC). The disease activity index of DSS rabbits increased up to 2.1 ± 0.4 (n = 6) at day 10 (controls <0.5). DSS induced a caecum‐localized pathology with crypt architectural distortion, stunted villous surface and inflammatory infiltrate in the lamina propria. The histopathology score reached a peak of 14.2 ± 4.9 (n = 4) at day 10 (controls 7.7 ± 0.9, n = 5). Expression profiling revealed an enrichment of IBD‐related genes in both LPMC and IEC. Innate inflammatory response, Th17 signalling and chemotaxis were among the pathways affected significantly. We describe a reproducible and reliable rabbit model of DSS colitis. Localization of the inflammation in the caecum and its similarities to IBD make this model particularly suitable to study TSO therapy in vivo.     

Chronic experimental colitis induced by dextran sulphate sodium (DSS) is characterized by Th1 and Th2 cytokines

Oral administration of DSS has been reported to induce an acute and chronic colitis in mice. The aim of our study was to evaluate if the chronic phase of DSS-induced colitis was characterized by a Th1/Th2 response and how this would relate to mucosal regeneration. Swiss Webster mice were fed 5% DSS in their drinking water for 7 days, followed by 2–5 weeks consumption of water. Control mice received only water. The animals were killed at 3 and 6 weeks after induction. Their colons were isolated for histology and immunohistochemistry, using specific MoAbs for T and B cells, macrophages, interferon-gamma (IFN-γ), IL-4 and IL-5. Colons were scored for inflammation, damage and regeneration. Two weeks after stopping DSS the colonic epithelium had only partially healed. Total colitis scores were still increased, especially in the distal colon, which was due to more inflammation, damage and less regeneration. In areas of incomplete colonic healing the basal parts of the lamina propria contained macrophages and CD4⁺ T cells. These CD4⁺ T cells showed a focal increase of IFN-γ and IL-4 staining compared with control animals. These findings were still observed 5 weeks after stopping DSS in some mice, albeit less extensive. Chronic DSS-induced colitis is characterized by focal epithelial regeneration and a Th1 as well as Th2 cytokine profile. We postulate that chronic immune activation mediated by both populations of Th cells can interfere with colonic healing and can play a role in the pathogenesis of chronic colitis.     

Intravenous immunoglobulin (IVIG) treatment of experimental colitis induced by dextran sulfate sodium in rats

We investigated the therapeutic effect and immunological action mechanism of IgG in experimental colitis induced by 3% dextran sulfate sodium in rats. Intravenous injection of homologous (rat) IgG (400 mg/kg per day) caused a significant suppression of occult blood discharge and ulcerative lesions in the colon, while no suppressive effect was observed in the case of heterologous (human) IgG. The positive effect of rat IgG on the lesions was also clearly shown by the histological examinations. Generation of proinflammatory cytokines, i.e. tumour necrosis factor-alpha (TNF-α) and IL-1α, in the lesions was found to be inhibited by administration of rat IgG. Little or no suppressive action was exerted by human IgG. Careful examination of recruited T cells and macrophages, both of which are thought to play important roles in the development of ulcerative colitis, indicated that rat IgG, but not its human counterpart, decreased the number of immunocompetent cells in colonic mucosa. Meanwhile, in an in vitro study, both forms of IgG were shown to suppress production of TNF-α and IL-1α from lamina propria mononuclear cells isolated from rat colon. These findings suggest that, mainly by suppressing recruitment of immunocompetent cells into the lesions, homologous IgG may reduce the occurrence of colitis.     

The COX-2 inhibitor, rofecoxib, ameliorates dextran sulphate sodium induced colitis in mice

Objective: We have evaluated the efficacy of the selective cyclo-oxygenase (COX)-2 inhibitor, rofecoxib, for the prevention of experimental colitis.Material and methods: To induce colitis BALB/c mice received 5% dextran sulphate sodium (DSS) in their drinking water continuously for 7 days. Rofecoxib (2.5–10 mg/kg body weight, p.o.) was administered throughout the treatment period with DSS. Colitis was quantified by a clinical damage score, colon length, weight loss, stool consistency and rectal bleeding. Inflammatory response was assessed by neutrophil infiltration, determined by histology and myeloperoxidase (MPO) activity. Interleukin (IL)-1, prostaglandin (PG)E₂ and PGD₂ levels in colon mucosa and the immunohistochemical expression of COX-1 and –2 were also studied.Results: The COX-2 inhibitor ameliorated severe colitis, reduced the degree of inflammation through reduction of neutrophil infiltration and IL-1 levels. PGE₂, and PGD₂ synthesis were significantly reduced in DSS-treated groups. Indeed, treatment with rofecoxib diminished the lost of COX-1 caused by DSS in the crypt epithelium whereas expression of COX-2 remained unaffected.Conclusions: Rofecoxib is protective in acute DSS – induced colitis, probably by reducing neutrophil infiltration, inhibiting up-regulation of IL-1 and returning to normal COX-1 expression in the inflamed colonic mucosa.Received 19 April 2004; returned for revision 17 June 2004; accepted by I. Ahnfelt-Rønne 23 November 2004     

Reduced susceptibility to dextran sulphate sodium-induced colitis in the interleukin-2 heterozygous (IL-2) mouse

Summary Mice homozygous for an inactivation of the interleukin-2 (IL-2) gene develop a T-cell dependent colitis. Heterozygous (IL-2+/-) mice are clinically healthy but have been shown to express reduced levels of IL-2 in the colon. Splenocytes from the IL-2+/- mice had a poorer proliferative response to polyclonal T-cell activation and these mice have reduced numbers of intestinal regulatory T cells (CD4+ CD25+ cells) when compared to wild type mice. When exposed to dextran sulphate sodium (DSS) IL-2+/- mice showed a markedly reduced susceptibility to DSS-induced colitis. While DSS treatment caused a marked increase in both CD4+ and CD8+ colonic T cells expressing increased levels of IL-2, IL-4, and IL-10 in wild type mice none of these changes were seen in IL-2+/- mice. On the contrary, cytokine expression in intestinal T cells of IL-2+/- mice was actually reduced after DSS treatment. These results suggest that reduced levels of IL-2 leads to attenuated activation and function of intestinal T cells in IL-2+/- mice and a failure to react adequately to DSS exposure.     

Use of bioluminescence imaging to track neutrophil migration and its inhibition in experimental colitis

Inflammatory bowel disease (IBD) is associated with neutrophil infiltration into the mucosa and crypt abscesses. The chemokine interleukin (IL)‐8 [murine homologues (KC) and macrophage inflammatory protein (MIP)‐2] and its receptor CXCR2 are required for neutrophil recruitment; thus, blocking this engagement is a potential therapeutic strategy. In the present study, we developed a preclinical model of neutrophil migration suitable for investigating the biology of and testing new drugs that target neutrophil trafficking. Peritoneal exudate neutrophils from transgenic β‐actin‐luciferase mice were isolated 12 h after intraperitoneal injection with thioglycollate, and were assessed phenotypically and functionally. Exudate cells were injected intravenously into recipients with dextran sodium sulphate (DSS)‐induced colitis followed by bioluminescence imaging of whole‐body and ex vivo organs at 2, 4 and 16–22 h post‐transfer. Anti‐KC antibody or an isotype control were administered at 20 µg/mouse 1 h before transfer, followed by whole‐body and organ imaging 4 h post‐transfer. The peritoneal exudate consisted of 80% neutrophils, 39% of which were CXCR2⁺. In vitro migration towards KC was inhibited by anti‐KC. Ex vivo bioluminescent imaging showed that neutrophil trafficking into the colon of DSS recipients was inhibited by anti‐KC 4 h post‐cell transfer. In conclusion, this study describes a new approach for investigating neutrophil trafficking that can be used in preclinical studies to evaluate potential inhibitors of neutrophil recruitment.     

Effects of ulinastatin in experimental colitis induced by dextran sulfate sodium in rats

Effects of ulinastatin in experimental colitis induced by dextran sulfate sodium in rats     

猪骨骼肌缺血预适应降低心肌缺血再灌注后基质金属蛋白酶的表达

目的观察猪骨骼肌缺血预适应对心肌缺血再灌注后坏死面积及心肌MMP-2、MMP-9及TIMP-1的影响。方法10只小型猪被随机分为缺血再灌注(I/R)组和远端预适应(RP)组。采用非开胸法建立心脏I/R模型,通过球囊堵塞左股动脉造成骨骼肌短暂缺血。以三硝基四氮唑红确定心肌梗死范围;以免疫组化和RT-PCR法测I/R心肌中MMP-2、MMP-9和TIMP-1表达及骨骼肌RP对此的影响。结果与I/R组相比,骨骼肌RP明显减少心肌梗死范围。在缺血区,RP明显降低MMP-2和MMP-9的表达,增加TIMP-1表达(P<0.05)。且RP明显减弱MMP-2和MMP-9 mRNA的表达,增强TIMP-1的mRNA表达(P<0.05)。结论骨骼肌缺血预适应心肌不仅可减少心肌坏死范围,还可能对心肌间质产生保护作用。     

Heterogeneity of serum activities of matrix metalloproteinases in chronic endometritis

Matrix metalloproteinases belong to the key molecules of tissue remodeling involved in physiological and pathological processes of the female reproductive system. Adequate levels of their expression in the endometrium are essential for effective implantation and uneventful pregnancy. Chronic inflammatory process in the endometrium is associated with low tissue expression of metalloproteinase-9. Histologically verified chronic endometritis is associated with low serum activities of metalloproteinases 2 and 9, which are restored after combined etiotropic therapy. We measured serum levels of metalloproteinases in patients with chronic endometritis concomitant with sterility and its changes during the first days after magnetotherapy. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 143, No. 4, pp. 455–457, April, 2007     

CD40 engagement modulates the production of matrix metalloproteinases by gingival fibroblasts

Chronic periodontitis is a destructive inflammatory disease linked with unbalanced production between matrix metalloproteinases (MMPs), such as interstitial collagenase (MMP-1) and stromelysin-1 (MMP-3) and their endogenous tissue inhibitors of MMPs (TIMPs). In addition to aberrant MMP-1 and MMP-3 expression, periodontal lesions are characterized by dense infiltrations of activated T lymphocytes which may interact with CD40-expressing gingival fibroblasts in the connective tissue via the CD40L-CD40 pathway. In this study we investigated whether CD40 cross-linking influenced MMP production by gingival fibroblasts. Therefore, we analysed the CD40L-induced MMP production by these fibroblasts in the presence of cytokines that are increased in periodontal lesions, such as IL-1β, tumour necrosis factor-alpha (TNF-α) and interferon-gamma (IFN-γ). We show that CD40 ligation on gingival fibroblasts resulted in a decrease of their MMP-1 and MMP-3 production, while MMP-2 and TIMP-1 production were unaffected as determined by Western blot. This down-regulatory effect of CD40 engagement on MMP-1 and MMP-3 production by gingival fibroblasts was also present when MMP production was up-regulated by IL-1β and TNF-α or down-regulated by IFN-γ. These results suggest that CD40 ligation on gingival fibroblasts leads to a restraining of MMP-1 and MMP-3 production by gingival fibroblasts and thereby may be an important mechanism in the retardation of further periodontal tissue damage.     

Role of matrix metalloproteinases and their tissue inhibitor of metalloproteinases in myxomatous change of cardiac floppy valves

To clarify the underlying cause of myxomatous changes in cardiac floppy valves, the expression of the matrix metalloproteinases (MMP) and the tissue inhibitors of metalloproteinases (TIMP) was investigated in cardiac valves. Valves were obtained from nine patients with floppy valves, from 13 patients with other valvular disease types, and from four patients with normal valves. Immunohistochemical analyses for MMP-2, MMP-9, TIMP-1, and TIMP-2, and gelatin zymography for MMP-2 and MMP-9 were performed. Compared with the spongiosa of normal valves, the myxomatous area of floppy valves had stronger immunohistochemical reaction to MMP-2 and MMP-9, and weaker reaction to TIMP-2. Activated MMP-2 and MMP-9 were detected in eight out of nine cases of floppy valves. Activated MMP-2 was detected at low levels in two cases of normal valves showing mild expansion of the spongiosa without macroscopic floppiness. The ratio of active/total MMP-2 and MMP-9 increased in floppy valves compared with normal valves. These results suggest that the imbalance between MMP and TIMP and the increased activity of MMP-2 and MMP-9 may correlate with myxomatous changes observed in floppy valves. Valves with a slight myxomatous change and activated MMP-2 may develop into floppy valves with increases in the activity of MMP.     

Role of Necl-5 in the pathophysiology of colorectal lesions induced by dimethylhydrazine and/or dextran sodium sulphate

Necl-5 is an immunoglobulin-like molecule that was originally identified as a poliovirus receptor. Although Necl-5 expression is often up-regulated in cancer cells, its pathophysiological significance in the development of cancer remains unclear. We investigated the roles of Necl-5 in the development of colitis-associated neoplasia. Necl-5-deficient mice were generated and treated with dimethylhydrazine (DMH) and/or dextran sodium sulphate (DSS) to induce colitis and its associated neoplasias. Colon tissues were examined for histology, Ki-67 expression by immunohistochemistry and K-ras gene mutation. Colon tumours occurred significantly less frequently in heterozygous (Necl-5(+/-)) or homozygous Necl-5-deficient (Necl-5(-/-)) mice than in wild-type (WT) mice with DMH/DSS treatment. Total ulcer index and inflammatory cell infiltration were significantly lower in Necl-5(-/-) mice than in WT mice with DSS alone or DMH/DSS treatment. Colon tumours in both WT and Necl-5(-/-) mice showed high cell proliferation ability but lacked K-ras mutation. The total Ki-67 labelling index in non-neoplastic colon epithelium was significantly higher in WT (45.9 +/- 0.94) than in Necl-5(+/-) (34.3 +/- 1.40) or Necl-5(-/-) (27.7 +/- 1.15) mice with DMH/DSS treatment (p < 0.001). Necl-5 plays a role in the development of colitis-associated cancer by up-regulating colonic mucosal cell proliferation.     

Local invasiveness of ameloblastoma. Role played by matrix metalloproteinases and proliferative activity

AIMS: Ameloblastoma is an odontogenic neoplasm characterized by local invasiveness and recurrence. In this study we analysed the role played by matrix metalloproteinases (MMPs) in the local invasiveness of ameloblastoma. We also attempted to establish a relationship between the presence of MMPs and the proliferative activity of ameloblastoma cells. METHODS AND RESULTS: Immunohistochemistry was carried out to detect different MMPs in formalin-fixed paraffin-embedded samples of human ameloblastoma. Immunohistochemistry, however, does not establish whether a given MMP is latent or active. To address this point, we carried out biochemical methods, namely zymography and Western blotting. Our results showed expression of latent and active forms of MMPs 1, 2 and 9 in ameloblastoma. These enzymes may digest bone matrix and release mitogenic factors, which would increase tumour proliferation. This possibility prompted us to study the proliferation of ameloblastoma cells located in close proximity to bone. Silver-stained nucleolar organizer region morphometry revealed that ameloblastoma cells in the vicinity of bone show increased proliferation, when compared with controls. CONCLUSIONS: Our results suggest an interdependent mechanism involving MMPs and proliferation of ameloblastoma cells, which may contribute to the local invasiveness of this tumour.     

In vivo treatment with the herbal phenylethanoid acteoside ameliorates intestinal inflammation in dextran sulphate sodium-induced colitis

Recently we demonstrated that in inflammatory bowel disease (IBD) macrophage-oxidative burst activity is increased and NADPH oxidase mRNA is induced. The herbal phenylethanoid acteoside isolated from Plantago lanceolata L. was shown to exhibit anti-oxidative potential. Using the dextran sulphate sodium (DSS)-induced colitis model, in this study we have assessed whether systemic application of acteoside affects colitis. Colitis was induced by DSS in Balb/c mice. Treatment with acteoside (120, 600 microg/mouse/day) was performed intraperitoneally. The colon lengths were determined. Colonic tissue was scored histologically (max. score 8) by a blinded investigator. T cells isolated from mesenteric lymph nodes (MLN) were stimulated with anti-CD3 antibody in the presence of interleukin (IL)-2 (final concentration 10 U/ml). After incubation for 24 h, IL-1beta, IL-6, IL-12 tumour necrosis factor (TNF)-alpha and interferon (IFN)-gamma levels in supernatants were analysed by the beadlyte cytokine detection system. Histological scoring of colonic tissue revealed that application of acteoside was followed by a significantly improved histological score. In acute colitis the histological score was 3.2 with acteoside versus 5.2 with phosphate-buffered saline (PBS) (P < 0.02). In chronic colitis both 120 microg (3.3 versus 5.2) or 600 microg acteoside (3.0 versus 5.2) significantly ameliorated colitis (both P < 0.02). Stimulated MLN from mice with chronic DSS-induced colitis treated with acteoside showed a significant down-regulation of IFN-gamma secretion (195 pg/ml with 600 microg acteoside versus 612 pg/ml with PBS, P < 0.02). Inhibition of oxidative burst activity with acteoside reduced mucosal tissue damage in DSS colitis and could be a therapeutic alternative for IBD treatment. Further studies of this agent are warranted.     

The effects of ulinastatin in experimental colitis induced by dextran sulfate sodium (DSS) in rats

The effects of ulinastatin in experimental colitis induced by dextran sulfate sodium (DSS) in rats     

Disease modifying effect of statins in dextran sulfate sodium model of mouse colitis

Objective: We evaluated the disease modifying effect of simvastatin and atorvastatin in Dextran Sulfate Sodium (DSS) model of colitis. Materials and methods: Thirty, 8-week old female Swiss-Webster mice were separated into 5 groups (n = 6/group). Colitis was induced by feeding 4 % DSS solution for 7 days. Following discontinuation of DSS, over the next 7 days, the groups orally received simvastatin (20 mg/kg/day), atorvastatin (60 mg/kg/day), vehicle only (0.75 % methylcellulose), subcutaneous 30 μg injections of anti-TNFα monoclonal antibody or intraperitoneal anti-mouse apolipoprotein A-I antibody respectively. Disease activity Index (DAI) was determined daily by a blinded investigator. Results: The mean reduction in DAI scores from day 7 to day 14 for anti-TNFα group, simvastatin and atorvastatin group were 74 %, 76 % and 64 %, respectively as compared to 41 % reduction in vehicle and anti-apolipoprotein A-I antibodytreated groups. Conclusions: This finding suggests that statins may have the ability to modify the disease activity in the DSS model of colitis and the disease modifying effect is comparable to anti-mouse TNFα treatment in this model. Received 23 October 2006; returned for revision 27 February 2007; accepted by I. Ahnfelt-R?nne 16 August 2007