Luteolin ameliorates dextran sulfate sodium-induced colitis in mice possibly through activation of the Nrf2 signaling pathway

BackgroundLuteolin has a reputation for being a safe and effective natural antioxidant that has strong radical scavenging and cell protective properties. The role of oxidative stress in inflammatory bowel disease (IBD) has been well established and is increasingly highlighted. Thus, we studied the protective effect of luteolin administration in a mouse model of experimental colitis.MethodsExperimental acute colitis was induced by administering 3% dextran sulfate sodium (DSS) in the drinking water of mice for 7 days. The disease activity index (DAI); colon length; histological assessment; mRNA levels of nuclear factor-erythroid 2-related factor 2 (Nrf2), tumor necrosis factor (TNF-α), interleukin-6 (IL-6), heme oxygenase-1 (HO-1), and NADP(H): quinone oxidoreductase 1 (NQO-1); protein expression of Nrf2 and inducible nitric oxide synthase (iNOS); colon malondialdehyde (MDA) levels; and the activity levels of colonic superoxide dismutase (SOD) and catalase (CAT) were examined.ResultsLuteolin (20 and 50 mg/kg) significantly attenuated the DAI, colon shortening and histological damage. In addition, luteolin administration effectively decreased the expression of inflammatory mediators, such as iNOS, TNF-α and IL-6. Luteolin also decreased the colonic content of MDA. The activities of colonic SOD and CAT and the levels of Nrf2 and its downstream targets, HO-1 and NQO1, were elevated by luteolin treatment.ConclusionThese observations indicate that luteolin may suppress experimental colitis through the Nrf2 signaling pathway.     

Autophagy induction by rapamycin ameliorates experimental colitis and improves intestinal epithelial barrier function in IL-10 knockout mice

BackgroundAn impairment of the intestinal barrier function is one of the major characteristics of Crohn’s disease (CD). This study aimed to evaluate the impact of autophagy induction by rapamycin on the intestinal epithelial barrier function in CD model mice.MethodsIL-10 knockout (IL-10 KO) mice were used as the human CD models in this study. All the mice were randomly assigned into four groups, (a) wild-type (WT) group; (b) IL-10 KO group; (c) IL-10 KO + rapamycin group and (d) IL-10 KO + 3-methyladenine (3-MA), containing 6 mice in each group. The disease activity index (DAI), histology, pro-inflammatory cytokines and chemotactic factors in colon tissues, intestinal and colonic permeability, distributions and expressions of tight junction (TJ) proteins, epithelial apoptosis of mice in four groups were evaluated and compared.ResultsAutophagy induction by rapamycin treatment ameliorated DAI and histological colitis, decreased pro-inflammatory cytokines (TNF-α, IFN-γ and IL-17) and chemotactic factors (CXCL-1 and CXCL-2), decreased intestinal and colonic permeability, improved the distribution and expression of TJ proteins in IL-10 KO mice.ConclusionAutophagy induction by rapamycin significantly improved intestinal barrier function and protected IL-10 KO mice from the experimental chronic colitis.     

Andrographolide sulfonate ameliorates experimental colitis in mice by inhibiting Th1/Th17 response

Inflammatory bowel disease (IBD) is a chronic, relapsing and remitting condition of inflammation involves overproduction of pro-inflammatory cytokines and excessive functions of inflammatory cells. However, current treatments for IBD may have potential adverse effects including steroid dependence, infections and lymphoma. Therefore new therapies for the treatment of IBD are desperately needed. In the present study, we aimed to examine the effect of andrographolide sulfonate, a water-soluble form of andrographolide (trade name: Xi-Yan-Ping Injection), on murine experimental colitis induced by 2, 4, 6-trinitrobenzene sulfonic acid (TNBS). Andrographolide sulfonate was administrated through intraperitoneal injection to mice with TNBS-induced colitis. TNBS-induced body weight loss, myeloperoxidase activity, shortening of the colon and colonic inflammation were significantly ameliorated by andrographolide sulfonate. Both the mRNA and protein levels of pro-inflammatory cytokines were reduced by andrographolide sulfonate administration. Moreover, andrographolide sulfonate markedly suppressed the activation of p38 mitogen-activated protein kinase as well as p65 subunit of nuclear factor-κB (NF-κB). Furthermore, CD4⁺ T cell infiltration as well as the differentiation of Th1 (CD4⁺IFN-γ⁺) and Th17 (CD4⁺IL17A⁺) subset were inhibited by andrographolide sulfonate. In summary, these results suggest that andrographolide sulfonate ameliorated TNBS-induced colitis in mice through inhibiting Th1/Th17 response. Our study shows that water-soluble andrographolide sulfonate may represent a new therapeutic approach for treating gastrointestinal inflammatory disorders.     

漆黄素激活SIRT1/Nrf2信号通路改善急性呼吸窘迫综合征大鼠铁死亡的研究

目的 探究漆黄素通过激活沉默信息调节因子1（SIRT1）/核因子E2相关因子2（Nrf2）信号通路对急性呼吸窘迫综合征大鼠铁死亡的影响。方法 将SD大鼠随机分为对照组、模型组以及漆黄素1、2、4 mg/kg组和漆黄素（4 mg/kg）＋SIRT1抑制剂（10 mg/kg EX-527）组,每组各14只。漆黄素、SIRT1抑制剂于造模前30 min ip给药,对照组、模型组ip给予等量生理盐水。除对照组外,其余各组大鼠均采用气管内滴注脂多糖法建立急性呼吸窘迫综合征模型。检测支气管肺泡灌洗液（BALF）中炎性因子白细胞介素-6（IL-6）、肿瘤坏死因子-α（TNF-α）水平;测定肺组织湿/干质量比（W/D）;HE染色观察肺组织病理改变;检测肺组织中铁死亡相关指标活性氧（ROS）、铁、谷胱甘肽（GSH）、丙二醛（MDA）水平;免疫印迹法检测肺组织中SIRT1/Nrf2信号通路相关蛋白表达。结果 与模型组比较,漆黄素各剂量组BALF中IL-6、TNF-α水平降低,肺组织W/D比值降低,肺组织中ROS、铁、MDA水平降低,GSH水平升高,肺组织中SIRT1、核Nrf2蛋白水平升高（P<0.05）,且4 mg/kg漆黄素干预的改善效果更显著;在4 mg/kg漆黄素干预的基础上增加SIRT1抑制剂后,漆黄素的改善作用被削弱。结论 漆黄素对脂多糖诱导的急性呼吸窘迫综合征有保护作用,能够改善铁死亡,可能是通过激活SIRT1/Nrf2信号通路实现的。     

Enhancement of epithelial cell autophagy induced by sinensetin alleviates epithelial barrier dysfunction in colitis

OBJECTIVE Intestinal epithelial barrier dysfunction is a key pathology of colitis. Autophagy of epithelial cells maintains homeostasis of the intestinal barrier by inhibiting apoptosis and stimulating degradation of the tight junction protein claudin-2. METHODS This study investigated the effects and mechanism of activity of sinensetin, a polymethylated flavonoid isolated from tangerine peel and citrus, on intestinal barrier dysfunction in colitis. Animal model of colitis were established by intracolonic administration of 2, 4, 6-trinitrobenzene sulfonic acid and oral treatment with dextran sulfate sodium. Epithelial barrier function was evaluated by measuring the serum recovery of fluorescein isothiocyanate-4 k D dextran in vivo and transepithelial electrical resistance in Caco-2 cells, respectively. Epithelial cell autophagy assayed by autophagosome formation and expression of autophagy-related protein. RESULTS Sinensetin reversed colitis-associated increase in intestinal permeability, significantly promoted epithelial cell autophagy,and further decreased epithelial cel apoptosis, and reduced mucosal claudin-2. Sinenstetin alleviated colitis symptoms rats and mice with colitis. Knockdown of 5′ adenosine monophosphate-activated protein kinase(AMPK) reversed the promotion of epithelial autophagy by sinensetin.CONCLUSION Sinensetin significantly alleviated intestinal barrier dysfunction in colitis by promoting epithelial cell autophagy, and further inhibiting apoptosis and promoting claudin-2 degradation. The results highlighted novel potential benefits of sinensetin in colitis.     

Polydatin ameliorates DSS-induced colitis in mice through inhibition of nuclear factor-kappaB activation

Nuclear factor- κB (NF- κB) plays a pivotal role in the regulation of immune and inflammatory responses. The real-time expression level of NF- κB reflects the development of ulcerative colitis (UC). Polydatin has vast pharmacological activities, including inhibiting the production of inflammatory mediators, inducing the production of antioxidants, regulating immune function, etc. The purpose of this study was to investigate the potential inhibitory effects of polydatin on NF- κB pathway activation in a mouse UC model. The results showed that polydatin treatment downregulated NF- κB p65 activity and expression, blocked the expression of TNF- α, IL-6 and IL-1 β at both mRNA and protein levels, decreased myeloperoxidase (MPO) activity, and alleviated inflammatory damage of colitis in mice with UC (p < 0.05), suggesting that the anti-inflammation effects of polydatin can be attributed, at least partially, to the blocking of the NF- κB pathway.     

黄连素调节鞘氨醇激酶-1-磷酸鞘氨醇信号通路抗糖尿病小鼠肾损伤的研究

目的研究黄连素对四氧嘧啶诱导的糖尿病小鼠肾损伤的保护作用及其对糖尿病小鼠肾脏鞘氨醇激酶-1-磷酸鞘氨醇(SphK-S1P)信号通路的抑制效应。方法四氧嘧啶诱导的糖尿病小鼠采用黄连素(300 mg.kg-1.d-1)灌胃给药12周,正常组和糖尿病组小鼠给予同体积的溶媒。采用Re-al-time PCR技术检测肾组织中SphK1、TGF-β1、FN、ColⅣ的基因;Western blot法检测肾脏组织中SphK1、FN、ColⅣ的蛋白表达;LC-MS/MS检测肾脏组织中SphK1活性和S1P含量。结果黄连素明显抑制糖尿病小鼠血糖,肾重/体重比、血尿素氮、血肌酐和24 h尿蛋白异常增高;抑制肾脏肥大、纤维连接蛋白和Ⅳ型胶原积聚。此外,黄连素明显减少肾脏SphK1活性、mRNA和蛋白表达,降低S1P的生成。结论黄连素发挥抗糖尿病小鼠肾损伤的作用可能与抑制肾脏SphK-S1P信号通路的激活相关联。     

Overexpressed SIRT6 ameliorates doxorubicin-induced cardiotoxicity and potentiates the therapeutic efficacy through metabolic remodeling

Since the utilization of anthracyclines in cancer therapy, severe cardiotoxicity has become a major obstacle. The major challenge in treating cancer patients with anthracyclines is minimizing cardiotoxicity without compromising antitumor efficacy. Herein, histone deacetylase SIRT6 expression was reduced in plasma of patients treated with anthracyclines-based chemotherapy regimens. Furthermore,overexpression of SIRT6 alleviated doxorubicin-induced cytotoxicity in cardiomyocytes, and potentiated c...     

Colifagina, a novel preparation of 8 lysed bacteria ameliorates experimental colitis

Immune reactivity towards the bacterial intestinal flora plays an important part in the pathogenesis of inflammatory bowel disease. Administration of probiotic bacteria has beneficial effects on infectious and inflammatory diseases, principally in bowel disorders. However, little is known about the administration of soluble bacterial antigens in intestinal inflammation. We investigated the therapeutic effects of colifagina in experimental colitis. To assess this effect, C57BL/6 mice with dextran sulphate sodium-induced colitis were treated with colifagina, or with a placebo, for a period of 10 days. The mice were monitored, and inflammation was assessed by disease activity index (DAI). Analysis of fecal IgA concentration and measurement of IgA and inflammatory chemokine production in organ colonic culture was performed by ELISA. Clinically and histologically, bacterial-lysate-treated mice revealed significantly fewer DAI and a reduction of colonic histological inflammation. Treatment of healthy mice with colifagina significantly increased the fecal concentration of IgA and IgA production in organ culture. Colifagina administration in DSS-treated mice significantly increased the fecal concentration of IgA and IgA production in organ culture. MIP-1, MIP-2 and RANTES concentrations in colonic organ culture were significantly lower in colifagina-treated mice than in the placebo group. The use of colifagina is effective in amelioration of murine colitis.     

Lymphtoxin beta receptor-Ig ameliorates TNBS-induced colitis via blocking LIGHT/HVEM signaling.

LIGHT is a member of the TNF superfamily, which is transiently expressed on the surface of activated T lymphocytes and immature dendritic cells. Its known receptors are herpesvirus entry mediator (HVEM) prominently in T lymphocytes, and lymphtoxin beta receptor (LTbetaR) in stromal cells or nonlymphoid hematopoietic cells. Previous studies have shown that overexpression of LIGHT on T cells could lead to lymphocytes activation, inflammation, and tissue destruction focused on intestinal mucosal tissues. To address the role of LIGHT/HVEM signaling in colonic inflammation, an experimental colitis model induced by rectal administration of trinitrobenzene sulfonic acid (TNBS) was given a soluble LTbetaR-Ig fusion protein as a competitive inhibitor of LIGHT/HVEM pathway. Marked elevation of LIGHT expression was detected in colonic tissue of the experimental colitis. Treatment with LTbetaR-Ig significantly attenuated the progression and histological manifestations of the colonic inflammation and reduced the production of inflammatory cytokines including TNF-alpha, IL-1beta and IL-8. Moreover, LTbetaR-Ig treatment significantly down-regulated LIGHT expression, leading to reduced lymphocytes, particularly CD4+ T cells, infiltrating into the colonic inflammation tissue as shown by histological analysis. In addition, comparison of the therapeutic effects on TNBS-induced colitis between LTbetaR-Ig and mesalazine showed that both treatments were equally efficacious. We postulated that blockade of LIGHT/HVEM signaling by LTbetaR-Ig may ameliorate TNBS-induced colitis by down-regulating LIGHT expression, and therefore we envision that LTbetaR-Ig would prove to a promising strategy for the clinical treatment of inflammatory bowel disease.     

叶黄素通过SIRT1/NLRP3信号通路提高人视网膜色素上皮细胞存活率的机制研究 #br#

目的 探讨叶黄素对高浓度葡萄糖诱导后人视网膜色素上皮细胞（ARPE-19细胞）内过氧化应激反应、炎症反应与细胞增殖活性的改善作用及调控机制。方法 使用不同浓度的叶黄素和高浓度葡萄糖同时处理ARPE-19细胞后,应用 CCK-8 检测细胞增殖活性变化,应用酶联免疫吸附试验检测炎性细胞因子水平变化,应用 CMH2DCFDA探针法检测活性氧（ROS）水平变化,应用荧光定量PCR检测SIRT1与NLRP3 mRNA表达水平变化。结果 在高葡萄糖环境下,ARPE-19细胞内炎性细胞因子白细胞介素（IL）-1β、IL-6、IL-18、肿瘤坏死因子（TNF）-α和ROS的表达水平显著高于对照组（P＜0.05）,细胞存活率低于对照组（P＜0.01）。与葡萄糖组比较,叶黄素组SIRT1 mRNA表达水平和细胞存活率显著上调,而 NLRP3 mRNA 表达水平显著下调（P＜0.05）。结论 叶黄素可通过 SIRT1/NLRP3信号通路改善人视网膜色素上皮细胞内的过氧化应激反应与炎症反应,进而提高细胞存活率。     

Isoliquiritigenin ameliorates dextran sulfate sodium-induced colitis through the inhibition of MAPK pathway

Isoliquiritigenin (isoLQ), a chalcone found in licorice, has shown a variety of biological activity including anti-inflammatory and antioxidative effects, and the distribution of isoLQ in gastrointestinal tract was higher than any other tissues. Thus, we evaluated whether or not isoLQ attenuated the dextran sulfate sodium (DSS)-induced colitis by observing the physiological changes (body weight loss, diarrhea, bleeding stool, overall disease activity index (DAI) scores, colon length), histopathological analysis and myeloperoxidase (MPO) activities of esophagus and colon. Also, the MAPK pathways including phosphorylation of ERK1/2, p38, and AKT, and the activation of NK-κB were evaluated in colon tissue. Interestingly, the reduction of body weight and colon length, increase of diarrhea, bloody stool, DAI scores and MPO activity, and histologic disturbances in DSS-induced colitis were recovered by isoLQ treatment. Also, isoLQ treatment suppressed the phosphorylation of ERK1/2 and p38, and the activation of NK-κB compared to those in DSS-induced colitis mice. In addition, the distributions of isoLQ in colon were relatively higher in DSS-induced colitis models. All of these results suggested that isoLQ has potential activity to ameliorate the DSS-induced colitis through the inhibition of MAPK pathway.     

Formononetin ameliorates DSS-induced ulcerative colitis in mice through induction of Nrf2 in colons

Isoflavone formononetin (FN) is a main active component of red clover (Trifolium pratense L.), a medicinal plant possessing antitumorigenic and antioxidant properties. In the present study, we aimed to examine the effect of FN on dextran sulfate sodium (DSS)-induced ulcerative colitis (UC) in mice. The results showed that FN (25, 50 mg/kg) markedly attenuated the loss of body weight, the disease activity index (DAI), shortening of colon length and tissue injury induced by DSS treatment. In addition, the levels of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and cyclooxygenase-2 (COX-2) were also significantlyreduced in FN treatment group compared with the DSS group. Moreover, several representative oxidative stress parameters in colorectum, including superoxide dismutase (SOD), methane dicarboxylic aldehyde (MDA), myeloperoxidase (MPO) and 8-oxoguanine, were markedly ameliorated. In this study, we also found that the expression of Nrf2 was increased by FN treatment.However, symptoms of UC were not ameliorated in Nrf2 knockout mice. Taken together, FN could prevent the development of UC through activating of Nrf2 axis, and the protective effect was Nrf2 dependent. Our results demonstrated that FN might be a potential therapeutic agent in the treatment of UC.     

Inhibition of Ras-GTPase signaling by FPTIII ameliorates development of cardiovascular dysfunction in diabetic-hypertensive rats

We studied the effect an inhibitor of Ras-GTPase (FPTIII, 1.5 mg/kg alt diem for 4 weeks) on mean arterial pressure (MAP), urine protein, vascular reactivity and cardiac function in streptozotocin (STZ)-induced diabetes in control normotensive (WKY) and spontaneously hypertensive rats (SHR). The increased urinary protein in STZ-treated WKY (D-WKY) and STZ-treated SHR (D-SHR) were significantly lower in FPTIII treated D-WKY and D-SHR. The abnormal vascular responsiveness to endothelin-1, angiotensin II, carbachol or histamine in isolated carotid artery from D-WKY and D-SHR was improved by chronic treatment with FPTIII. In isolated perfused hearts, recovery of left ventricular function from 40 min of global ischemia was significantly improved in FPTIII treated D-WKY and D-SHR. These results show that treatment with FPTIII can attenuate development of abnormal vascular reactivity and renal/cardiac dysfunction during simultaneous occurrence of hypertension and diabetes.     

Nafamostat mesilate attenuates colonic inflammation and mast cell infiltration in the experimental colitis

Serine proteases are important in the pathogenesis of intestinal inflammation. Recent studies have shown that nafamostat mesilate (NM) can inhibit the colonic mucosal inflammation induced by TNBS in rats. The aim of this study was to investigate the anti-inflammatory effects of NM on a DSS-induced colitis. Colitis was induced in female BALB/c mice by 5% dextran sulfate sodium (DSS) for 6 days. NM (2 or 20mg/kg body weight) was orally administered once a day for 6 days during treatment of the mice with DSS. The inflammatory response of the colon was assessed 1 week after DSS treatment. NM at a high dose, but not at a low dose significantly decreased disease activity index (DAI) and myeloperoxidase (MPO) induced by DSS. Furthermore, NM (20mg/kg) inhibited the production of tumor necrosis factor (TNF)-α, cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) in the colonic tissues treated with DSS. The increase in chymase activity by DSS treatment was also attenuated by the administration of NM (20mg/kg). NM (20mg/kg) significantly decreased the colonic mucosal injury and the infiltrated mast cell number induced by DSS. These results indicate that NM might inhibit the colonic inflammation through inhibition of both chymase activity and mast cell infiltration in colon tissues of DSS-induced colitis.     

Dextran sodium sulphate-induced colitis perturbs muscarinic cholinergic control of colonic epithelial ion transport

1. Neuronal cholinergic input is an important regulator of epithelial electrolyte transport and hence water movement in the gut. 2. In this study, colitis was induced by treating mice with 4% (w v(-1)) dextran sodium-sulphate (DSS)-water for 5 days followed by 3 days of normal water. Mid-colonic segments were mounted in Ussing chambers and short-circuit current (Isc, indicates net ion movement) responses to the cholinergic agonist, carbachol (CCh; 10(-4) M)+/-tetrodotoxin, atropine (ATR), hexamethonium (HEX), naloxone or phenoxybenzamine were assessed. 3. Tissues from mice with DSS-induced colitis displayed a drop in Isc in response to CCh (-11.3+/-3.3 microA/cm(2)), while those from control mice showed a transient increase in Isc (76.3+/-13.0 microA/cm(2)). The DeltaIsc in colon from DSS-treated mice was tetrodotoxin-sensitive, atropine-insensitive and was reversed by hexamethonium (HEX+CCh=16.7+/-7.8 microA/cm(2)), indicating involvement of a nicotinic receptor. 4. CCh induced a drop in Isc in tissues from controls only when they were pretreated with the cholinergic muscarinic receptor blocker, atropine: ATR+CCh=-21.3+/-7.0 microA/cm(2). Nicotine elicited a drop in Isc in Ussing-chambered colon from both control and DSS-treated mice that was TTX-sensitive. 5. The drop in Isc evoked by CCh challenge of colonic tissue from DSS-treated mice or ATR+CCh challenge of control tissue was not significantly affected by blockade of opiate or alpha-adrenergic receptors by naloxone or phenoxybenzamine, respectively. 6. The data indicate that DSS-colitis reveals a nicotinic receptor that becomes important in cholinergic regulation of ion transport.