中药肠炎清治疗小鼠葡聚糖硫酸钠所致结肠炎的机制

目的:探讨肠炎清的疗效及其机制.方法:以葡聚糖硫酸钠(DSS)饮水法复制小鼠实验性结肠炎40只,随机平均分为4组:肠炎清中药组、柳氮磺胺吡啶(SASP)西药组、肠炎清和SASP中西药结合组和模型组.观察肠炎清(灌胃剂量为0.2mL/(20g?d)、1次/d、疗程7d)对疾病活动指数(DAI)和肠组织髓过氧化物酶(MPO)活性及TNF-α、IL-1β和IL-6mRNA表达的影响.结果:与模型组相比,肠炎清可降低DAI(1.413±0.835vs2.167±0.911,P<0.05)和MPO活性(72.4±0.590nkat/gvs117.0±0.902nkat/g,P<0.05),并降低肠组织TNF-α(0.841±0.190vs1.320±0.282,P<0.05)、IL-1β(0.641±0.095vs0.920±0.082,P<0.05)和IL-6mRNA(1.241±0.247vs1.620±0.312,P<0.05)的表达,中西医结合组以上指标下降更为明显(DAI:0.608±0.449;MPO:27.3±0.211;TNF-α:0.339±0.081;IL-1β:0.239±0.073;IL-6:0.639±0.141)(P<0.01).肠炎清与柳氮磺胺吡啶(SASP)的作用相当(P>0.05).结论:肠炎清可治疗DSS结肠炎,其降低肠组织TNF-α、IL-1β和IL-6mRNA的表达可能是其疗效机制之一.     

小檗碱对老龄大鼠葡聚糖硫酸钠所致结肠炎黏膜组织结构及相关炎症因子表达的影响

目的 探讨小檗碱(Ber)对葡聚糖硫酸钠(DSS)诱导结肠炎老年大鼠的疗效及其可能的机制. 方法 以DSS饮水法复制18月大鼠实验性结肠炎30只, 随机平均分为3组:正常对照组、结肠炎模型(DSS)组和Ber治疗(DSS+Ber)组.观察Ber对疾病活动指数(DAI)和结肠黏膜结构及肿瘤坏死因子α(TNF-α)、核转录因子кB (NF-кB)、细胞间黏附分子-1(ICAM-1)、诱生型一氧化氮合酶(iNOS)表达的影响. 结果 给予DSS后老龄大鼠出现典型的结肠炎的变化.Ber治疗可显著降低结肠炎老龄大鼠的DAI评分[(1.862±0.623)分比(2.317±0.729)分,P ＜0.05]和组织学病理评分[(1.347±0.548)分比(1.945±0.853)分,P＜0.05].Ber治疗显著降低肠组织TNF-α[(832.5±178.8 ) pg/g比(1438.2±312.5) pg/g,P＜0.05],并降低黏膜组织NF-κB[(0.154±0.623)比(0.213±0.058),P＜0.05], ICAM-1[(0.124±0.076)比(0.156±0.101),P＜0.05]和iNOS(0.098±0.048比0.125±0.053,P＜0.05). 结论 Ber可治疗老龄大鼠的DSS结肠炎, 其降低肠组织TNF-α、IL-1β和IL-6 mRNA的表达可能是其疗效机制之一.     

Impaired nitrergic innervation in rat colitis induced by dextran sulfate sodium

BACKGROUND & AIMS: The pathophysiological role of neuronal nitric oxide synthase (nNOS) in colitis remains unknown. METHODS: We investigated colonic transit, nonadrenergic, noncholinergic (NANC) relaxation, nNOS activity, and nNOS synthesis in the myenteric plexus in dextran sulfate sodium (DSS)-induced colitis in rats. RESULTS: Oral administration of 5% DSS for 7 days induced predominant distal colitis and delayed colonic transit. In the proximal colon, carbachol-, sodium nitroprusside-, and electrical field stimulation (EFS)-induced responses were not different between control and DSS-treated rats. In the distal colon, EFS-evoked cholinergic contraction, NANC relaxation, and orphanin FQ-induced contraction were significantly impaired in DSS-treated rats compared with those in control rats, but carbachol- and sodium nitroprusside-induced responses remained intact in DSS-treated rats. The number of nNOS-immunopositive cells, catalytic activity of NOS, and nNOS synthesis in the colonic wall were significantly reduced in the distal colon of DSS-treated rats. In contrast, the number of PGP 9.5-immunopositive cells and PGP 9.5 synthesis in the colonic wall remained intact in the distal colon of DSS-treated rats. CONCLUSIONS: These results suggest that impaired NANC relaxation in the distal colon is associated with reduced activity and synthesis of nNOS in the myenteric plexus in DSS-induced colitis.     

Venular constriction of submucosal arterioles induced by dextran sodium sulfate

BACKGROUND: Leukocyte and platelet adherence in postcapillary venules has been speculated to induce constriction of closely paired arterioles. This mechanism was investigated in the current study, in a model of intestinal inflammation induced by dextran sodium sulfate (DSS; 5,000 molecular weight). METHODS: Closely paired, parallel arterioles and venules in the submucosa of the mouse intestine were observed using fluorescent intravital microscopy. Arterioles in control mice were compared to arterioles in mice given 5% DSS in drinking water for 11 days. RESULTS: DSS induced an inflammatory response in which fluorescently labeled leukocytes and platelets were observed adhering to venules. Arterioles constricted and flow decreased significantly when the arterioles were paired with venules having adherent leukocytes and platelets, although the decreases in flow and diameter appeared to be more dependent on platelet than leukocyte adherence. No significant constriction was observed in arterioles paired with venules having minimal platelet adherence. Inhibition of thromboxane with 100 mg/kg ozagrel induced a significant dilation of arterioles in DSS mice that was absent in control mice. CONCLUSION: The results are consistent with a proposed mechanism in which thromboxane constricts submucosal arterioles when the arterioles are closely paired with platelet-bearing venules in DSS-induced inflammation.     

氧化苦参碱对葡聚糖硫酸钠诱导大鼠结肠炎的抗炎作用机制研究

目的　探讨氧化苦参碱 (OM )对葡聚糖硫酸钠 (DSS)诱导结肠炎的抗炎作用及其作用机制。方法　建立DSS诱导的大鼠结肠炎模型。SD大鼠 2 6只 ,随机分为OM处理组 (A组 ,10只 )、OM未处理组 (B组 ,10只 )和正常对照组 (C组 ,6只 )。A组第 1～ 11天肌内注射OM 6 3mg·kg-1·d-1,第 4～ 11天饮用 2 %DSS溶液 ;B组第 1～ 11天肌注与A组OM等体积的生理盐水 ,第 4～ 11天饮用 2 %DSS溶液 ;C组肌注生理盐水同B组 ,正常饮水。观察大鼠的腹泻、便血症状及结肠组织学改变 ,ELISA测定血清肿瘤坏死因子 α(TNF α)和白细胞介素 6 (IL 6 )水平 ,免疫组化检测结肠黏膜核转录因子 κB(NF κB)活性及细胞间粘附分子 1(ICAM 1)的表达。结果　与OM未处理组相比 ,OM处理组大鼠的症状和结肠黏膜组织学损伤显著改善 (P值均 <0 .0 5 ) ,TNF α ,IL 6 ,NF κB和ICAM 1显著降低 (P值均 <0 .0 5 )。结论　OM可抑制NF κB活化 ,降低TNF α、IL 6和ICAM 1的生成 ,从而减轻结肠炎性损伤和腹泻、便血症状。     

Effect of adiponectin on murine colitis induced by dextran sulfate sodium

BACKGROUND & AIMS: Adiponectin, an adipose tissue-derived hormone, exhibits anti-inflammatory properties and has various biological functions, such as increasing insulin sensitivity, reducing hypertension, and suppressing atherosclerosis, liver fibrosis, and tumor growth. The aim of the present study was to determine the effect of adiponectin on intestinal inflammation. METHODS: We investigated the effect of adiponectin on dextran sulfate sodium (DSS)-induced colitis by using adiponectin-knockout (APN-KO) mice and an adenovirus-mediated adiponectin expression system. We also examined the contribution of adiponectin deficiency to trinitrobenzene sulfonic acid (TNBS)-induced colitis. In vitro, we examined the effect of adiponectin on intestinal epithelial cells. RESULTS: After administration of 0.5% DSS for 15 days, APN-KO mice developed much more severe colitis compared with wild-type mice. The messenger RNA expression levels of chemokines were significantly higher in the colonic tissues of DSS-treated APN-KO mice compared with wild-type mice, accompanied by increased cellular infiltration, including macrophages. Adenovirus-mediated supplementation of adiponectin significantly attenuated the severity of colitis, but there were no differences in the severity of TNBS-induced colitis between the 2 groups. Adiponectin receptors were expressed in intestinal epithelial cells, and adiponectin inhibited lipopolysaccharide-induced interleukin-8 production in intestinal epithelial cells. CONCLUSIONS: Adiponectin is protective against DSS-induced murine colitis, probably due to the inhibition of chemokine production in intestinal epithelial cells and the following inflammatory responses, including infiltration of macrophages and release of proinflammatory cytokines.     

瑞巴匹特预防葡聚糖硫酸酯钠诱发的小鼠结肠炎疗效观察及作用机制初探

目的近年氧自由基在溃疡性结肠炎(UC)发病过程中作用受到关注,一种新型的黏膜保护剂瑞巴匹特被认为具有清除氧自由基的作用,有望成为治疗溃疡性结肠炎的新药物。本文观察瑞巴匹特灌肠和灌胃治疗葡聚糖硫酸酯钠(DSS)诱发的小鼠结肠炎效果并探讨可能的作用机制。方法 3%DSS予8周龄雄性BALB/c小鼠自由饮用7 d制成小鼠结肠炎模型。予DSS前5 d开始瑞巴匹特(45 mg/kg/d)灌肠或灌胃治疗直到造模结束,处死小鼠取结肠组织,测量小鼠体重、结肠长度,进行大体和病理评分,分光光度法测定髓过氧化物酶、丙二醛含量,免疫组化法测定核因子κB(NFκB)表达水平,RT-PCR法测定过氧化物酶体增殖体激活受体γ(PPARγ)mRNA表达。结果与安慰剂对照组比较,瑞巴匹特灌肠和灌胃治疗组小鼠大体和病理评分显著改善,髓过氧化物酶活性、丙二醛含量、NFκB活性明显降低,PPARγmRNA的表达显著升高。结论瑞巴匹特可有效预防DSS诱发的小鼠结肠炎,其抑制炎症作用至少部分与清除氧自由基,从而维持局部PPARγ表达和抑制NFκB活性有关。     

Dietary inulin improves distal colitis induced by dextran sodium sulfate in the rat

OBJECTIVES: Inulin stimulates intracolonic generation of butyrate and growth of lactic acid bacteria. This study investigated whether inulin protects against colitis. METHODS: Rats with dextran sodium sulfate colitis received inulin either orally (1% in drinking water, or 400 mg/day) or by enema. Matched groups received vehicle. In addition, fecal water obtained from inulin-fed rats was administered by enema to rats with colitis and compared with fecal water from control rats. Finally, rats with colitis received daily enemas of either butyrate (at 40 or 80 mmol/L) or vehicle. Inflammation was assessed by eicosanoid asssay in rectal dialysates and MPO activity in colonic tissue. Mucosal lesions were blindly scored by microscopic examination. Luminal pH was measured from cecum to rectum by a surface microelectrode. RESULTS: Oral inulin prevented inflammation, as evidenced by lower lesion scores (p < 0.05), decreased release of mediators (p < 0.05), and lower tissue MPO (p < 0.05) as compared with controls. Inulin induced acidic environment (pH <7.0) from cecum to left colon and increased counts of lactobacilli. Fecal water from inulin-fed rats also reduced scores (p < 0.05) and inflammation (p < 0.05). However, inulin or butyrate enemas had no effect. CONCLUSIONS: Oral inulin reduces the severity of dextran sodium sulfate colitis. The effect seems to be mediated by modification of the intracolonic milieu.     

双歧杆菌对葡聚糖硫酸钠(DSS)诱导的小鼠结肠炎肠道黏膜的保护作用及其对NF-κB的影响

目的随着对炎症性肠病(inflammatory bowel disease,IBD)发病机制的深入研究,肠道微生态与免疫系统的密切关系日益受到重视。本研究旨在评价双歧杆菌单一活菌制剂对葡聚糖硫酸钠(dextran sulfate sodium,DSS)诱导的小鼠结肠炎肠道黏膜的保护作用及其可能作用机制。方法 BALB/c小鼠饮用含7%DSS的饮用水10d,诱导小鼠亚急性结肠炎的模型,模拟人类溃疡性结肠炎。空白对照组(n=6)饮用未添加DSS的饮用水。饮用DSS的小鼠(n=37)随机分为5组,分别给予不同的药物治疗:①提前给予双歧杆菌治疗组(Pre-BIF):在小鼠暴露于DSS前10d及暴露过程中给予双歧杆菌治疗;②强的松治疗组(PRED):在小鼠暴露于DSS同时给予强的松治疗;③双歧杆菌治疗组(BIF):小鼠暴露于DSS的同时给予双歧杆菌治疗;④强的松+双歧杆菌联合治疗组(PRED+BIF):小鼠暴露于DSS的同时给予强的松和双歧杆菌联合治疗;⑤生理盐水对照组(NS):小鼠暴露于DSS的同时给予生理盐水作为对照。不同药物皆以溶液形式灌胃给药。从4方面评价各组的处理反应:①一般情况:包括体重、结肠长度、大体评分;②组织病理评分;③化学比色法检测病变组织髓过氧化物酶(MPO)活性;④免疫组织化学方法检测活化的NF-κB。结果 Pre-BIF治疗组和BIF治疗组的大体评分、组织病理评分、MPO活性与NS对照组相比明显改善(P0.01;P0.05)。Pre-BIF治疗组、BIF治疗组和PRED+BIF治疗组的NF-κB活性评分显著低于NS对照组(P均0.01)。结论双歧杆菌对小鼠DSS结肠炎肠道黏膜具有保护作用,提前应用保护效果更好。双歧杆菌对肠道黏膜的保护作用与抑制NF-κB的活化有关。     

Immune response in mouse experimental cholangitis associated with colitis induced by dextran sulfate sodium

BACKGROUND AND AIM: Primary sclerosing cholangitis is frequently complicated by inflammatory bowel disease. Although many colitis models have been reported, little information has been obtained about complicated cholangitis. The aim of the present study was to determine whether hepatobiliary disorders occur in mice experimental colitis, and to clarify the underlying mechanisms. METHODS: The CD-1 mice were fed standard chow with or without dextran sulfate sodium in the drinking water, followed by histological examination of the liver and colon. Mononuclear cells were isolated from these organs, and cytokine production was assessed. The CD4/CD8 ratio and the population of natural killer T (NKT) cells were analyzed by flow cytometry. RESULTS: Inflammatory cell infiltration and focal necrosis in the liver were found in 33% of treated mice. In treated mice, the CD4/CD8 ratio increased in the liver, whereas no such change was found in the colon. Also an increase of interferon-gamma and a decrease of interleukin-4 production were observed. The NKT cell population showed transient changes in the liver and colon. CONCLUSIONS: Hepatobiliary disorders were complicated with experimental colitis in CD-1 mice. Immunological findings indicate a T-helper-1-dominant underlying mechanism, and NKT cells may play a pathogenic role in this model. This model may help to elucidate the relationship between hepatic and colonic inflammations.     

Oxidative stress and metabolism in animal model of colitis induced by dextran sulfate sodium

BACKGROUND AND AIM: Ulcerative colitis is a chronic inflammatory disease of the gastrointestinal tract. Its etiology remains unclear, but it appears to result from a dysregulated immune response, with infiltration of phagocytic leukocytes into the mucosal interstitium. The production and release of reactive oxygen species by immune cells seems to play a crucial role in physiopathology of colitis. The aim of this work was to evaluate the effects of N-acetylcysteine (NAC) and deferoxamine (DFX) in the treatment of colitis induced by dextran sulfate sodium (DSS). METHODS: The effects of NAC and DRX on rats with DSS-induced colitis were determined by measuring intestinal parameters of oxidative stress and mitochondrial function, inflammatory response and bowel histopathological alterations. RESULTS: DSS increased white blood cells count and NAC and DFX did not prevent this effect. However, DSS increased mitochondrial respiratory chain complex IV in colon of rats and NAC and DFX prevented this alteration. In addition, thiobarbituric acid reactive substances were increased in colon of DSS-treated rats. NAC and DFX, when taken together, prevented this effect. Complex II and succinate dehydrogenase were not affected by DSS, as protein carbonyl content. CONCLUSIONS: It is speculated that NAC and DFX might be useful for treatment of colitis, but further research is necessary to clarify these effects.     

Anti-inflammatory mechanism of oxymatrine in dextran sulfate sodium-induced colitis of rats

AIM: To investigate the anti-inflammatory mechanism of oxymatrine in dextran sulfate sodium (DSS)-induced colitis of rats. METHODS: Acute colitis was induced by giving 2% DSS orally in drinking water for 8 d. Twenty-six male rats were randomized into oxymatrine-treated group (group A, 10 rats), DSS control (group B, 10 rats) and normal control (group C, 6 rats). The rats in group A were injected muscularly with oxymatrine at the dosage of 63 mg/(kg·d) from d 1 to 11 and drank 2% DSS solution from d 4 to 11. The rats in group B were treated with 0.9% saline in an equal volume as group A and drank 2% DSS solution from d 4 to 11. The rats in group C were treated with 0.9% saline as group B from d 1 to 11 and drank water normally. Diarrhea and bloody stool as well as colonic histology were observed. The levels of serum tumor necrosis factor-α(TNF-α) and interleukin-6 (IL-6) were determined by ELISA, and nuclear factor-κB (NF-κB) activity and the expression of inter-cellular adhesion molecule-1(ICAM-1) in colonic mucosa were detected by immunohistochemistry method. RESULTS: Compared with DSS contror group, the inflammatory symptoms and histological damages of colonic mucosa in oxymatrine-treated group were significantly improved, the serum levels of TNF-α, IL-6, and the expression of NF-κB, ICAM-1 in colonic mucosa were significantly reduced. CONCLUSION: The fact that oxymatrine can reduce the serum levels of TNF-α, IL-6, and the expression of NF-κB and ICAM-1 in colonic mucosa in DSS-induced colitis of rats indicates that oxymatrine may ameliorate the colonic inflammation and thus alleviate diarrhea and bloody stool.     

Intestinal blood flow in murine colitis induced with dextran sulfate sodium

The aim of this study was to assess whether colitis induced by dextran sulfate sodium (DSS; 10% in tap water for 7 days) in BALB/c mice is associated with changes in intestinal blood flow. After anaesthesia, systemic hemodynamic variable and regional blood flows and resistances in various organs were measured in both control and DSS-treated mice. Mean arterial blood pressure was significantly lower in DSS-treated mice than in controls (56 ± 4 vs 66 ± 3 mm Hg; P < 0.05), but no differences were found in regional blood flows to or vascular resistances in the lungs, liver, stomach, small intestine (upper, middle, and lower part), cecum, mesentery + pancreas, spleen, kidneys, brain, and skin. However, compared to the control mice, blood flows in the middle (0.88 ± 0.13 vs 0.55 ± 0.09 ml/min/g; P < 0.05) and distal (0.69 ± 0.11 vs 0.29 ± 0.05 ml/min/g; P < 0.05) colon were significantly higher, and vascular resistances in the proximal (0.87 ± 0.21 vs 1.36 ± 0.21 mm Hg min/ml/100 g; P < 0.05), middle (0.60 ± 0.10 vs 1.46 ± 0.35 mm Hg min/ml 100 g; P < 0.05) as well as distal (0.90 ± 0.25 vs 2.67 ± 0.49 mm Hg min/ml/100 g; P < 0.05) colon were significantly lower in mice with experimental colitis. Interestingly, there was a gradient in the intestinal blood flow in control mice from the upper small intestine (2.79 ± 0.72 ml/min/g) down to the distal colon (0.29 ± 0.05 ml/min/g); such a gradient was also present in the colitis mice. It is concluded that DSS-induced colitis in mice is associated with microcirculatory disturbances in the colon, mainly in its middle and distal parts.