Intracerebroventricular administration of anti-endothelin-1 IgG selectively upregulates endothelin-A and kappa opioid receptors

Endothelin (ET) type A receptor antagonists enhance morphine-induced antinociception and restore morphine analgesia in morphine tolerant rats [Peptides 23 (2002) 1837; Peptides 24 (2003) 553]. These studies suggest that the central ET and opioid systems functionally interact. To explore this idea further, we determined the effect of i.c.v. administration of anti-ET-1 IgG (rabbit) on brain opioid receptor and ET receptor expression. Three days after implanting cannula into the lateral ventricle, male Sprague-Dawley rats were administered 10 microl (i.c.v.) of either control rabbit IgG (2.5 microg/microl) or anti-ET IgG (2.5 microg/microl) on day 1, day 3, and day 5. On day 6, animals were killed and the caudate and hippocampus collected. Anti-ET IgG had no significant effect on expression, measured by Western blots, of mu, delta or ET-B receptors, but increased kappa opioid (59%) and ET-A (33%) receptor protein expression in the caudate. [35S]-GTP-gamma-S binding assays demonstrated that anti-ET IgG decreased [D-Ala2-MePhe4, Gly-ol5]enkephalin efficacy, but not potency in the caudate. Control experiments showed that there was no detectable rabbit IgG in caudate and hippocampal samples. These results suggest that ET in the CSF negatively regulates kappa opioid and ET-A receptors in certain brain regions. These findings support the hypothesis that CSF neuropeptides have regulatory effects and further demonstrate a link between ET and the opioid receptor system.     

Potential role for ET-2 acting through ETA receptors in experimental colitis in mice

Objective and design

This study attempted to clarify the roles of endothelins and mechanisms associated with ET_A/ET_B receptors in mouse models of colitis.

Materials and methods

Colitis was induced by intracolonic administration of 2,4,6-trinitrobenzene sulfonic acid (TNBS, 1.5 mg/animal) or dextran sulfate sodium (DSS, 3%). After colitis establishment, mice received Atrasentan (ET_A receptor antagonist, 10 mg/kg), A-192621 (ET_B receptor antagonist, 20 mg/kg) or Dexamethasone (1 mg/kg) and several inflammatory parameters were assessed, as well as mRNA levels for ET-1, ET-2 and ET receptors.

Results

Atrasentan treatment ameliorates TNBS- and DSS-induced colitis. In the TNBS model was observed reduction in macroscopic and microscopic score, colon weight, neutrophil influx, IL-1β, MIP-2 and keratinocyte chemoattractant (KC) levels, inhibition of adhesion molecules expression and restoration of IL-10 levels. However, A192621 treatment did not modify any parameter. ET-1 and ET-2 mRNA was decreased 24 h, but ET-2 mRNA was markedly increased at 48 h after TNBS. ET-2 was able to potentiate LPS-induced KC production in vitro. ET_A and ET_B receptors mRNA were increased at 24, 48 and 72 h after colitis induction.

Conclusions

Atrasentan treatment was effective in reducing the severity of colitis in DSS- and TNBS-treated mice, suggesting that ET_A receptors might be a potential target for inflammatory bowel diseases.

     

Endothelin and endothelin receptors A and B in the human testis

 Human testicular capillaries interconnect Leydig cells and seminiferous tubules. Microcirculation and blood flow are therefore essential for the maintenance of spermatogenesis. The expression and the localisation of ET (endothelin) and its receptors in testicular tissue, in seminiferous tubules and in human testicular capillaries were studied. ET-1 mRNA was detected in whole testicular tissue and in seminiferous tubules whereas isolated testicular capillaries were negative. Big ET-1 (Big endothelin 1) and ET peptides were localised in Leydig and Sertoli cells whereas interstitial and intramural capillaries (within the lamina propria) remained unstained. ET was also found in mature spermatids. ET-A (endothelin receptor A) mRNA was detected in seminiferous tubules and whole testicular tissue whereas testicular blood vessels were negative. ET-A immunostaining was displayed in Leydig and Sertoli cells and in spermatids. ET-B (endothelin receptor B) mRNA was detected in whole testicular tissue, seminiferous tubules and in testicular capillaries. ET-B peptide was prominent in Leydig cells, peritubular cells, endothelial cells and pericytes of interstitial and intramural capillaries as well as in vascular endothelial and smooth muscle cells. From these results we conclude that ET produced in Leydig and Sertoli cells can act in a paracrine manner via ET-B on the human testicular microvasculature and the peritubular cells. The presence of both ET-A and ET-B in Leydig cells and of ET-A in Sertoli cells leads to the assumption that ET could influence these cells as an autocrine factor. Accepted: 9 October 1998     

Regular immunohistochemical localization of endothelin-1 and endothelin-B receptor in normal, hyperplastic and neoplastic human adrenocortical cells

The locallzation of endothelin (ET)-l/blg ET-1, ET-3/big ET-3, ET-A and ET-B receptor was Immunohistochemlcally examined in human adrenal glands composed of 36 normal cases, nine hyperplasla, 70 adenomas and seven carcinomas of cortical cells. In normal adrenals, ET-1/blg ET-1 and ET-B receptor were regularly detected In the cortical cells, especially in the zona fasciculata for ET-1 and zone glomerulosa for ET-B receptor but not in the medulla, while ET-A receptor localized occasionally in endothelial cells or rarely in cortical cells and ET-3/blg ET-3 was very limited In the cortical cells. In hyperplasia, adenoma and carcinoma, ET-1 /big ET-1 and ET-B receptor showed frequent localization, although focal distrlbutlon of the ET-B receptor was rather predominant in these groups. ET-A receptor and ET-3/big ET-3 were very Infrequently expressed. Functioning versus non-functioning and hypertensive versus normotenshe cases revealed no significant differences in the frequency of posltive cells for ET-l /big ET-1, ET-3/big ET-3, ET-A receptor or ET-B receptor. Alternatively, the frequency of lmmunoreactivtty to ET-1/big ET-1 or ET-B receptor significantly decreased in hyperplasia, adenoma and carcinoma, when compared wlth that of normal adrenal cortex.
The present study, therefore, indicates that ET-1 /big ET-1 and ET-B receptor are a prevalent Iigand-receptor system In normal and hyperplastic/neoplastic adrenocortical cells, even wkh a malignant prdle, and may contribute in maintalnlng adrenocortical cell function or cell viability but not cell growth or systemic hypertension.     

Different endothelin receptor subtypes are involved in phospholipid signalling in the proximal tubule of rat kidney

 Phospholipid signalling mediated by endothelin (ET) receptor subtypes was studied in the rat proximal tubule. In freshly isolated proximal tubule cells, ET-1, ET-2 and sarafotoxin S6c (S6c) evoked an increase in 1,2-diacylglycerol (DAG), inositol 1,4,5-trisphosphate (InsP ₃) and phosphocholine (PCho), suggesting stimulation of both phosphatidyl-inositol 4,5-bisphosphate- and phosphatidyl-choline-specific phospholipase C (PLC), while ET-3 increased only DAG and PCho, presumably via phosphatidyl-choline-dependent PLC. Renal cortical slices were also stimulated by the above-mentioned agonists, followed by isolation of either brush border (BBM) or basolateral (BLM) membranes for which mass measurements of inositol lipids and DAG were performed. In BBM, DAG increased in response to ET-1, ET-2 and ET-3, and was followed by protein kinase C (PKC) translocation to the BBM, while in BLM, DAG formation and translocation of PKC were observed only in response to ET-3, suggesting spatial segregation of signalling systems between two membane domains of proximal tubule cells. Tyrphostine, pertussis toxin (PTX) or cholera toxin (CTX) did not influence ET-mediated signalling in either of the membranes, suggesting involvement of PTX- and CTX-insensitive G-protein-mediated stimulation of PLCβ by ET receptors. ET-dependent stimulation of PLC in BBM and BLM was used as a tool to examine the presence of different ET receptor subtypes in these two cell membrane domains. BQ123, an inhibitor of ET_A receptors, did not prevent ET-1-mediated signalling in BBM, but an ET_A,B antagonist, bosentan, inhibited ET-3-mediated signalling in BBM. In addition, an ET_B agonist, S6c, stimulated PLC in BBM. Neither BQ123 nor bosentan inhibited ET-3 signalling in BLM. Therefore, these data strongly suggest the presence of ET_B receptors coupled to phosphatidyl-inositol 4,5-bisphosphate- and phosphatidyl-choline-dependent PLC in BBM and ET_C receptors linked to phosphatidyl-choline-dependent PLC in BLM. Received: 21 November 1995 / Received after revision and accepted: 5 February 1996     

Endothelins-1/3 and endothelin-A/B receptors expressing glial cells with special reference to activated microglia in experimentally induced cerebral ischemia in the adult rats

We reported previously that amoeboid microglial cells (AMC) in the developing brain exhibited endothelins (ETs) expression which diminished with advancing age and was undetected in microglia in the more mature brain. This study sought to explore if microglia in the adult would be induced to express ETs in altered conditions. By immunofluorescence microscopy, ETs and endothelin (ET)-B receptor were undetected in microglial cells in sham-operated and normal control rats. However, in adult rats subjected to middle cerebral artery occlusion (MCAO), lectin labeled activated microglia which occurred in large numbers in the marginal zones in the ischemic cortex at 3 days and 1 week intensely expressed ETs specifically endothelin (ET)-1 and ET-B receptor; ET-3 and ET-A receptor were absent in these cells. By RT-PCR and ELISA, ET-1 and -3 mRNA and protein expression level was progressively increased in the ischemic cerebral cortex after MCAO compared with the controls. ET-A and ET-B receptor mRNA and protein levels were concomitantly up-regulated. It is suggested that increased release of ET-1 following MCAO by massive activated microglia can exert an immediate constriction of local blood vessels bearing ET-A receptor. ET-1 may also interact with activated microglia endowed with ET-B receptor via an autocrine manner that may be linked to chemokines/cytokines production. ET-1, ET-3 and ET-B receptor were also localized in reactive astrocytes along with some oligodendrocytes. We conclude that activated microglia together with other glial cells in the marginal zone after MCAO are the main cellular source of ETs that may be involved in regulation of vascular constriction and glial chemokines/cytokines production. However, dissecting the role of individual component of the endothelin system in the various glial cells, notably activated microglia, would be vital in designing of an effective therapeutic strategy for clinical treatment of stroke in which microglial cells have been implicated.     

Bosentan, an endothelin receptor antagonist, ameliorates collagen-induced arthritis: the role of TNF-α in the induction of endothelin system genes

Objective

Endothelins (ETs) are involved in several inflammatory events. The present study investigated the efficacy of bosentan, a dual ETA/ETB receptor antagonist, in collagen-induced arthritis (CIA) in mice.

Treatment

CIA was induced in DBA/1J mice. Arthritic mice were treated with bosentan (100?mg/kg) once a day, starting from the day when arthritis was clinically detectable.

Methods

CIA progression was assessed by measurements of visual clinical score, paw swelling and hypernociception. Histological changes, neutrophil infiltration and pro-inflammatory cytokines were evaluated in the joints. Gene expression in the lymph nodes of arthritic mice was evaluated by microarray technology. PreproET-1 mRNA expression in the lymph nodes of mice and in peripheral blood mononuclear cells (PBMCs) was evaluated by real-time PCR. The differences were evaluated by one-way ANOVA or Student’s t test.

Results

Oral treatment with bosentan markedly ameliorated the clinical aspects of CIA (visual clinical score, paw swelling and hyperalgesia). Bosentan treatment also reduced joint damage, leukocyte infiltration and pro-inflammatory cytokine levels (IL-1β, TNFα and IL-17) in the joint tissues. Changes in gene expression in the lymph nodes of arthritic mice returned to the levels of the control mice after bosentan treatment. PreproET mRNA expression increased in PBMCs from rheumatoid arthritis (RA) patients but returned to basal level in PBMCs from patients under anti-TNF therapy. In-vitro treatment of PBMCs with TNFα upregulated ET system genes.

Conclusion

These findings indicate that ET receptor antagonists, such as bosentan, might be useful in controlling RA. Moreover, it seems that ET mediation of arthritis is triggered by TNFα.     

The role of transient receptor potential vanilloid 1 in mechanical and chemical visceral hyperalgesia following experimental colitis

The transient receptor potential vanilloid 1 receptor (TRPV1) is an important nociceptor involved in neurogenic inflammation. We aimed to examine the role of TRPV1 in experimental colitis and in the development of visceral hypersensitivity to mechanical and chemical stimulation. Male Sprague–Dawley rats received a single dose of trinitrobenzenesulfonic acid (TNBS) in the distal colon. In the preemptive group, rats received the TRPV1 receptor antagonist JYL1421 (10 μmol/kg, i.v.) or vehicle 15 min prior to TNBS followed by daily doses for 7 days. In the post-inflammation group, rats received JYL1421 daily for 7 days starting on day 7 following TNBS. The visceromotor response (VMR) to colorectal distension (CRD), intraluminal capsaicin, capsaicin vehicle (pH 6.7) or acidic saline (pH 5.0) was assessed in all groups and compared with controls and naïve rats. Colon inflammation was evaluated with H&;E staining and myeloperoxidase (MPO) activity. TRPV1 immunoreactivity was assessed in the thoraco-lumbar (TL) and lumbo-sacral (LS) dorsal root ganglia (DRG) neurons. In the preemptive vehicle group, TNBS resulted in a significant increase in the VMR to CRD, intraluminal capsaicin and acidic saline compared the JYL1421-treated group (P<0.05). Absence of microscopic colitis and significantly reduced MPO activity was also evident compared with vehicle-treated rats (P<0.05). TRPV1 immunoreactivity in the TL (69.1±4.6%) and LS (66.4±4.2%) DRG in vehicle-treated rats was increased following TNBS but significantly lower in the preemptive JYL1421-treated group (28.6±3.9 and 32.3±2.3 respectively, P<0.05). JYL1421 in the post-inflammation group improved microscopic colitis and significantly decreased the VMR to CRD compared with vehicle (P<0.05, ≥30 mm Hg) but had no effect on the VMR to chemical stimulation. TRPV1 immunoreactivity in the TL and LS DRG was no different from vehicle or naïve controls. These results suggest an important role for TRPV1 channel in the development of inflammation and subsequent mechanical and chemical visceral hyperalgesia.     

BQ123及Phosphoramidon单独及联合应用对心力衰竭患者的血管活性作用

在阻断内皮素A受体（ET－A）的基础上,观察内皮素转化酶（ECE）抑制剂对血管舒缩功能的影响。12例心力衰竭患者及12例正常志愿者,在用BQ123阻断ET－A的基础上,接受ECE抑制剂Phosphoramidon,观察前臂血流量（FBF）的变化。经肱动脉注射BQ123后,FBF均呈相同程度升高。随后注射Phosphoramidon使FBF均进一步增加。但在心力衰竭患者,BQ123的作用时间明显短于正常人。提示在阻断ET－A受体的基础上,抑制ET的合成可产生进一步的扩血管作用。BQ123在心力衰竭患者的作用时间明显缩短,表明药物在体内被高浓度的ET迅速置换。     

Role of neurokinin 1 receptors in dextran sulfate-induced colitis: studies with gene-deleted mice and the selective receptor antagonist netupitant

Objective and design

The function of the neurokinin 1 (NK1) receptor was investigated in the DSS-induced mouse colitis model using NK1 receptor-deficient mice and the selective antagonist netupitant.

Subjects

Colitis was induced by oral administration of 20 mg/ml DSS solution for 7 days in C57BL/6 and Tacr1 KO animals (n = 5–7).

Treatment

During the induction, one-half of the C57BL/6 and Tacr1 KO group received one daily dose of 6 mg/kg netupitant, administered intraperitoneally, the other half of the group received saline, respectively.

Methods

Disease activity index (DAI), on the basis of stool consistency, blood and weight loss, was determined over 7 days. Histological evaluation, myeloperoxidase (MPO) measurement, cytokine concentrations and receptor expression analysis were performed on the colon samples.

Results

NK1 receptors are up-regulated in the colon in response to DSS treatment. DSS increased DAI, histopathological scores, BLC, sICAM-1, IFN-γ, IL-16 and JE in wildtype mice, which were significantly reduced in NK1 receptor-deficient ones. NK1 receptor antagonism with netupitant significantly diminished DAI, inflammatory histopathological alterations, BLC, IFN-γ, IL-13 and IL-16 in wildtype mice, but not in the NK1-deficient ones. MPO was similarly elevated and netupitant significantly decreased its activity in both groups.

Conclusions

NK1 receptor antagonism could be beneficial for colitis via inhibiting different inflammatory mechanisms.     

Analysis of ET‐A and ET‐B receptors using an isolated perfused rat lung preparation

Aims and Methods: The pulmonary and vascular effects of endothelin‐1 receptor activation were studied in isolated perfused and ventilated lung preparations from rat. The responses to endothelin‐1 (ET‐1) and the endothelin B (ET_B) receptor agonist sarafotoxin 6c (S6c) were characterized using the endothelin A (ET_A)‐receptor antagonist FR 139317, the ET_B‐receptor antagonist BQ 788 and the combined ET_A/ET_B‐receptor antagonist Bosentan. The respiratory parameter airway conductance (G_aw) and the vascular parameter perfusion flow were analysed simultaneously. Results: Concentration–response curves for ET‐1 administered intra‐arterially revealed that its most potent effect was on the vascular side while S6c had a more potent effect on airway conductance. ET‐1, given as a bolus dose intra‐arterially (100 μL of 0.2 nm ), induced a strong‐ and long‐lasting contraction of the vasculature while only a less pronounced contraction was seen in the airways. Neither of the antagonists had a significant effect per se on G_aw or perfusion flow. FR 139317 reduced the effect of ET‐1 on perfusion flow by about 50%, while airway conductance was augmented. BQ 788 enhanced the decrease in perfusion flow by ET‐1 while G_aw was not influenced. The combined ET_A/ET_B antagonist Bosentan powerfully prevented the ET‐1‐induced decrease in G_aw but did not alter its reduction in perfusion flow. Conclusions: The potent effect of ET‐1 on the vascular side of the lung is mediated mainly through ET_A receptors, whereas both ET_A and ET_B receptors are involved in G_aw in the rat lung.     

Expression of endothelin system in neuroblastic tumors: close association of endothelin-1 and endothelin B receptor expression with differentiation of tumor cells

Although a critical role of the endothelin (ET) system in differentiation of neural crest cells has been reported, implication of the ET system in human neuroblastic tumors has not been fully elucidated. We immunohistochemically examined for localization of ET-1, ET-3, ET-A receptor (ET-A), and ET-B receptor (ET-B) in 24 ganglioneuromas, 8 ganglioneuroblastomas, 37 neuroblastomas, 14 normal sympathetic ganglia, and 10 fetal adrenal glands with regard to neuroblastic cell differentiation. Neuroblasts in fetal adrenal glands expressed ET-B (100%) alone. Immature ganglionic cells in sympathetic ganglia of fetus frequently expressed ET-1 (86%) and ET-B (100%), while ET-A was occasionally detected (28%). Ganglionic cells of mature adult ganglia consistently harbored ET-1 (100%) and, infrequently, ET-3 (21%) or ET-B (29%). Expression of ET-1 and ET-B was closely associated with tumor cell differentiation: the expression frequency of ET-1 or ET-B was 16% or 46% in neuroblastomas; 100% or 88% in ganglioneuroblastomas; and 96% or 92% in ganglioneuromas. In contrast, ET-3 and ET-A showed no association with tumor cell differentiation: the expression frequency of ET-3 or ET-A was 26% or 14% in neuroblastomas; 63% or 13% in ganglioneuroblastomas; and 29% or 21% in ganglioneuromas. In conclusion, ET-1 and ET-B are expressed with differentiation of neuroblastic tumors.     

Involvement of PPARγ in the protective action of tropisetron in an experimental model of ulcerative colitis

Inflammatory bowel disease (IBD) is a chronic inflammation of the gastrointestinal (GI) tract. Tropisetron, a selective 5-HT₃ receptor antagonist, is highly used to counteract chemotherapy-induced emesis. Previous studies revealed the anti-in?ammatory properties of this drug. The aim of this study was to evaluate the role of peroxisome proliferator-activated receptor gamma (PPARγ) receptor in the protective effect of tropisetron in an animal model of ulcerative colitis. Experimental colitis was induced by a single intra-colonic instillation of 4% (V/V) acetic acid in male rats. Tropisetron (3?mg/kg) and GW9662 (PPARγ antagonist) (5?mg/kg) were given twice daily for 2 days after colitis induction. Forty-eight hours after induction of colitis, colon was removed and macroscopic and microscopic features were given. Moreover, colonic concentrations of malondialdehyde (MDA), nitric oxide (NO), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) levels, myeloperoxidase (MPO), and PPARγ activity were assessed. Both macroscopic and histopathological features of colonic injury were markedly ameliorated by tropisetron. Likewise, levels of NO, MDA, TNF-α, and IL-1β diminished significantly (p?p?相似文献   

Protective effect of geranylgeranylacetone on trinitrobenzene sulfonic acid-induced colitis in mice

Geranylgeranylacetone (GGA) has recently been reported to have a protective effect against ischemic, injurious and apoptotic stress in several tissues. The aim of this study was to determine the effect of GGA on colitis induced by 2,4,6-trinitrobenzene sulfonic acid (TNBS) in mice. Colitis was induced by intrarectal instillation of TNBS in 50% ethanol in BALB/c mice. Survival, change in body weight and change in wet colon weight were assessed. Histological score in the colon was evaluated 5 days after TNBS treatment. The level of myeloperoxidase (MPO) activity in the colon was also determined. Immunohistochemistry for CD4 in the colon was performed. In addition, the level of heat shock protein (HSP) 70 in the colon was determined by Western blot analysis. Mice were orally treated with GGA (300 mg/kg) 2 h before and every other day after starting TNBS administration. Treatment with GGA markedly improved the survival rate, and reduced the loss of body weight and loss of wet colon weight in mice with TNBS-induced colitis. GGA also suppressed the increase in MPO activity and the number of CD4-positive cells infiltrating the colons of mice with TNBS-induced colitis. Furthermore, treatment with GGA remarkably up-regulated the expression of HSP70 in the colons of mice with TNBS-induced colitis. Our results provide further evidence that GGA has therapeutic potential for intestinal inflammation.     

The effect of the cholinergic anti-inflammatory pathway on experimental colitis

Inflammatory bowel diseases (IBD) are characterized by proinflammatory cytokines, tissue damage and loss of neuron in inflamed mucosa, which implies the cholinergic anti-inflammatory pathway may be destroyed during the process of inflammatory response. In the study, we identified the effect of cholinergic agonist as anabaseine (AN) and nicotinic receptor antagonist as chlorisondamine diiodide (CHD) on trinitrobenzene sulfonic acid (TNBS)-induced colitis, to investigate the potential therapeutic effect of the cholinergic anti-inflammatory pathway on IBD. Experimental colitis was induced by TNBS at day 1, 10 mug AN or 1.5 mug CHD was injected i.p. to mouse right after the induction of colitis, and repeated on interval day till the mice were sacrificed at day 8. Colonic inflammation was examined by histological analysis, myeloperoxidase (MPO) activity, and the production of tumour necrosis factor (TNF)-alpha in tissue. Lamina propria mononuclear cells (LPMC) were isolated, and NF-kappaB activation was detected by western blot. The mice with colitis treated by AN showed less tissue damage, less MPO activity, less TNF-alpha production in colon, and inhibited NF-kappaB activation in LPMC, compared with those mice with colitis untreated, whereas the mice with colitis treated by CHD showed the worst tissue damage, the highest MPO activity, the highest TNF-alpha level, and enlarged NF-kappaB activation in LPMC. Agonist of the cholinergic anti-inflammatory pathway inhibits colonic inflammatory response by downregulating the production of TNF-alpha, and inhibiting NF-kappaB activation, which suggests that modulating the cholinergic anti-inflammatory pathway may be a new potential management for IBD.     

Preventive effects of Escherichia coli strain Nissle 1917 with different courses and different doses on intestinal inflammation in murine model of colitis

Objective

To analyze the in vivo effect of Escherichia coli Nissle 1917 (EcN) with different courses and different doses to Sprague–Dawley rats with trinitrobenzene sulfonic acid (TNBS)-induced colitis.

Methods

The probiotic was orally administered with different courses of treatment (with or without pre-administration) and different doses (10⁷–10⁹ CFU/day) to Sprague–Dawley rats with TNBS-induced colitis. Therapeutic effects, levels of cytokine in serum, mRNA and protein expression were analyzed.

Results

Oral EcN administration after TNBS-induced improved colitis dose dependently. In parallel, a reduction of disease activity index and colonic MPO activity together with a decreased level of TNF-α and a trend of increased IL-10 expression was detected. Pre-administration of 10⁷ CFU/day EcN to TNBS-treated rats resulted in a significant protection against inflammatory response and colons isolated from these rats exhibited a more pronounced expression of ZO-1 than the other groups. In the group of pre-administration of 10⁹ CFU/day, the condition was not improved but deteriorated.

Conclusions

This study convincingly demonstrates that pre-administration of probiotic EcN with low dose is able to protect colitis of rats and mediate up-regulation of ZO-1 expression, but long-term of high-dose EcN may do harm to colitis.     

Effects of Trefoil Peptide 3 on Expression of TNF-α, TLR4, and NF-κB in Trinitrobenzene Sulphonic Acid Induced Colitis Mice

The trefoil factor (TFF) peptides are major secretory products of mucus cells of the gastrointestinal tract. There were evidences that administration of recombinant human TFF3 is effective in treatment of models of colitis, but the mechanism of the effects of rTFF3 is not fully understood. The main aims of this study is to evaluate effects of intraperitoneal injection recombinant human TFF3 on the expression of tumour necrosis factor α (TNF-α), toll-like receptor 4(TLR4), and nuclear factor κB (NF-κB) in trinitrobenzene sulphonic acid (TNBS) induced colitis mice. Distal colitis was induced in BALB/C mice by intracolonic administration of TNBS in ethanol. Treated with administration rhTFF3 for treatment group(5 mg/ml; approximately 0.5 mg/mouse), and normal saline for control for 5 consecutive days. Colonic damage score, tissue myeloperoxidase (MPO) activity, TLR4, NF-κB mRNA expression, and tissue TNF-α, TLR4, NF-κB production were determined, respectively. Once daily application of hTFF3 for 5 days after TNBS/ethanol had been injected, both microscopic and macroscopic injury and inflammatory index had been reduced compared with controls. In addition, decreased tissue TNF-α, TLR4, NF-κB production, and TLR4, NF-κB mRNA expression had been found. This study has shown that hTFF3 may have therapeutic potential in the treatment of inflammatory bowel disease, and one of the mechanisms may related to inhibit the TLR4/NF-κB signaling pathways.     

Endothelin-1 induces organ-specific histamine liberation and neutrophil granulocyte accumulation in the rat

OBJECTIVE AND DESIGN: Enhanced production of endothelin-1 (ET-1) and the activation of mast cells (MCs) have been implicated in granulocyte sequestration. We compared local consequences of transient increases in circulating ET-1 in three separate circulatory beds in pentobarbital-anesthetized Wistar rats. MATERIALS AND METHODS: We determined whether pretreatment with ET-A receptor antagonist ETR-P1/fl peptide and MC stabilizer sodium cromoglycate would influence histamine- and granulocyte responses induced by 1 nmol/kg ET- 1 iv. Plasma and tissue histamine contents were monitored, myeloperoxidase (MPO) level was determined from heart, lung and intestinal biopsies. RESULTS: The ET-1 infusion caused significant plasma histamine elevations, enhanced MPO activity in all organs, decreased tissue histamine content in the lung and small bowel by approx. 50% , while the histamine content of heart did not change. ETR-P1/fl significantly decreased ET-1-induced intestinal and heart MPO changes, and inhibited histamine depletion in the small intestine but not in lung and heart tissues. Sodium cromoglycate inhibited the ET-1-induced neutrophil accumulation in the heart and intestine and did not influence MPO activity in the lung. CONCLUSION: ET-1 release participates in the process of histamine liberation and subsequent secondary granulocyte accumulation through tissue-specific activation of ET-A receptors. ET-1-induced direct effects are predominating in pulmonary neutrophil activation, while MC-associated secondary changes play important roles in intestinal granulocyte recruitment.     

内皮素-B受体在脑缺血大鼠脑内小胶质细胞中的表达

目的 研究脑缺血后内皮素-B(ET-B)受体在脑内激活的小胶质细胞中的表达变化,探讨ET-B受体与脑缺血的关系.方法 应用微创开颅法建立大鼠大脑中动脉闭塞(MCAO)模型,81只大鼠随机分为2h、6h、12h、1d、2d、3d和1周7个缺血组,以及正常对照组和假手术组(n=9).用抗凝集素(lectin)和抗ET-B抗...