Protection against dextran sodium sulfate-induced colitis by dehydroepiandrosterone and 7alpha-hydroxy-dehydroepiandrosterone in the rat

In this study the anti-oxidant effect of DHEA and 7alpha-hydroxy-DHEA against oxidative stress induced by colitis was investigated in vivo in rats. The two steroids were intraperitoneally injected once daily (50 mg/kg body weight) for 7 days before the induction of colitis that was effected by a daily treatment of 5% (w/v) dextran sodium sulfate (DSS) in drinking water for 7 days. This was quantified by the evidence of weight loss, rectal bleeding, increased wall thickness, and colon length. The inflammatory response was assessed by neutrophil infiltration after a histological examination and myeloperoxidase (MPO) activity measurement. Two markers of oxidative damage were measured in colon homogenates after the onset of DSS treatment: protein carbonyls and thiobarbituric acid-reacting substances. The colonic metabolism of corticosterone by 11beta-hydroxysteroid dehydrogenases types 1 and 2 (11beta-HSD) was investigated in control and treated animals. Results indicated that colitis caused a decrease in body weight and colon length. Severe lesions were observed in the colon with a reduced number of goblet cells which contained less mucins. The lesions were associated with increased MPO activity and oxidative damage. Colonic inflammation down and up regulated the 11beta-HSD2 and 11beta-HSD1, respectively. Treatments by DHEA and 7alpha-hydroxy-DHEA attenuated the inflammatory response when MPO activity decreased; but this did not increase the colonic oxidation of corticosterone into 11-dehydrocorticosterone. Both DHEA and 7alpha-hydroxy-DHEA exerted a significant anti-oxidant effect against oxidative stress induced by colitis through reducing the oxidative damage to proteins and lipids. This resulted in a moderate increase in the amount of colonic mucus. Both DHEA and 7alpha-hydroxy-DHEA may prove useful in the prevention or treatment of colitis.     

Influence of Aloe vera on collagen characteristics in healing dermal wounds in rats

Wound healing is a fundamental response to tissue injury that results in restoration of tissue integrity. This end is achieved mainly by the synthesis of the connective tissue matrix. Collagen is the major protein of the extracellular matrix, and is the component which ultimately contributes to wound strength. In this work, we report the influence of Aloe vera on the collagen content and its characteristics in a healing wound. It was observed that Aloe vera increased the collagen content of the granulation tissue as well as its degree of crosslinking as seen by increased aldehyde content and decreased acid solubility. The type I/type III collagen ratio of treated groups were lower than that of the untreated controls, indicating enhanced levels of type III collagen. Wounds were treated either by topical application or oral administration of Aloe vera to rats and both treatments were found to result in similar effects.     

The possible neurobehavioral protective effects of natural antioxidant against phototoxicity attenuation of antimicrobial quinolone group in rats

The fluoroquinolones absorb light in the 320 to 330 nm ultraviolet A (UV‐A) wavelength and produce reactive oxygen species (ROS) such as superoxide anion, hydroxyl radical, and hydrogen peroxide; thus, the photodynamic generation of ROS may be the basis of phototoxicity of quinolones in human beings and animals. This study aimed to evaluate the damaging effects of UV‐A radiation at different periods of exposure on rats' brains administered with ciprofloxacin. Ciprofloxacin administration in UV‐A exposed animals exaggerated the brain‐oxidative stress biomarkers and decreased the locomotor activity. Exposure of rats to UV‐A for 60 minutes induced a significant increase of malondialdehyde (MDA), myeloperoxidase (MPO), and a decrease in the values of superoxide dismutase (SOD), glutathione (GSH) compared to a normal one; these changes were UV‐A exposure time–dependent. However, the administration of vitamin C to the UV‐60‐treated group decreased the values of MDA, MPO, and shifted the values of SOD, GSH toward the normal values. Vitamin C, probably due to its strong antioxidant properties, could improve and partially counteract the toxic effect of UV‐A on oxidative stress parameters and prevent the damage in rat's brain tissues.     

NK-1 antagonist reduces colonic inflammation and oxidative stress in dextran sulfate-induced colitis in rats

Although substance P (SP) has been implicated as a mediator of neurogenic inflammation in the small intestine, little information is available regarding the role of SP in the pathogenesis of chronic ulcerative colitis. In this study, our aim was to investigate whether the intraperitoneal administration of a nonpeptide neurokinin-1 (NK-1) antagonist, CP-96345, which antagonizes the binding of SP to its NK-1 receptor, results in the attenuation of colonic inflammation induced in rats by 5% dextran sodium sulfate (DSS) in drinking water for 10 days compared with an inactive enantiomer, CP-96344. Disease activity was assessed daily for 10 days, after which colonic tissue damage was scored and myeloperoxidase activity and colon and urinary 8-isoprostanes were measured. Animals receiving DSS exhibited marked physical signs of colitis by day 5 compared with controls. Chronic administration of the NK-1 antagonist significantly reduced the disease activity index, mucosal myeloperoxidase activity, colonic tissue damage score, and mucosal and urinary levels of 8-isoprostanes compared with inactive enantiomer- or vehicle-injected (saline) animals receiving DSS alone. These data indicate that the administration of an NK-1 antagonist can attenuate colonic inflammation and oxidative stress and suggest a novel therapeutic approach in the treatment of chronic ulcerative colitis.     

Dihydroberberine,an isoquinoline alkaloid,exhibits protective effect against dextran sulfate sodium-induced ulcerative colitis in mice

BackgroundAs a chronic inflammatory disease, ulcerative colitis (UC) is relevant to a rising risk of colorectal cancer. Dihydroberberine (DHBB), a natural occurring isoquinoline alkaloid with various bioactivities, was found in many plants including Coptis chinensis Franch. (Ranunculaceae), Phellodendron chinense Schneid. (Rutaceae), and Chelidonium majus L. (Papaveraceae). However, its protective effect on UC is sparsely dissected out.PurposeTo explore the protective role and underlying mechanism of DHBB on a model of colitis.MethodsAcute colitis model was established by gavage with 3% dextran sulfate sodium (DSS) for 8 days. Influence of DHBB on DSS-induced clinical symptoms and disease activity index (DAI) was monitored and analyzed. Pathological injury of colon tissues was examined by hematoxylin-eosin and Alcian blue staining. The expression of intestinal mucosal barrier function proteins, immune-inflammation related biomarkers and signal pathway key targets were determined by ELISA kit, Western blot, immunohistochemistry and qRT-PCR.ResultsDHBB treatment effectively alleviated DSS-induced UC by relieving clinical manifestations, DAI scores and pathological damage, which exerted similar beneficial effect to azathioprine (AZA), and better than berberine (BBR). In addition, DHBB significantly improved the gut barrier function through up-regulating the levels of tight junction proteins and mucins. Furthermore, DHBB dramatically ameliorated colonic immune-inflammation state, which was related to the decrease of colonic pro-inflammatory cytokines and immunoglobulin through blocking TLR4/MyD88/NF-κB signal pathway.ConclusionThese results demonstrated that DHBB exerted a significant protective effect on DSS-induced experimental UC, at least partly through suppressing immune-inflammatory response and maintaining gut barrier function.     

Milk fat globule-EGF factor 8 is a critical protein for healing of dextran sodium sulfate-induced acute colitis in mice

Milk fat globule-EGF factor 8 (MFG-E8) has been shown to play an important role in maintaining the integrity of the intestinal mucosa and to accelerate healing of the mucosa in septic mice. Herein, we (a) analyzed the expression of MFG-E8 in the gut of wild-type (WT) C57BL/6 (MFG-E8(+/+)) mice with and without dextran sulfate sodium (DSS)-induced colitis, (b) characterized the pathological changes in intestinal mucosa of MFG-E8(+/+) and MFG-E8(-/-) mice with DSS-induced colitis and (c) examined the therapeutic role of MFG-E8 in inflammatory bowel disease by using DSS-induced colitis model. Our data documented that there was an increase in colonic and rectal MFG-E8 expression in MFG-E8(+/+) mice during the development of DSS colitis. MFG-E8 levels in both tissues decreased to below baseline during the recovery phase in mice with colitis. Changes in MFG-E8 gene expression correlated to the levels of inflammatory response and crypt-epithelial injury in both colonic and rectal mucosa in MFG-E8(+/+) mice. MFG-E8(-/-)mice developed more severe crypt-epithelial injury than MFG-E8(+/+) mice during exposure to DSS with delayed healing of intestinal epithelium during the recovery phase of DSS colitis. Administration of MFG-E8 during the recovery phase ameliorated colitis and promoted mucosal repair in both MFG-E8(-/-) and MFG-E8(+/+) mice, indicating that lack of MFG-E8 causes increased susceptibility to colitis and delayed mucosal healing. These data suggest that MGF-E8 is an essential protective factor for gut epithelial homeostasis, and exogenous administration of MFG-E8 may represent a novel therapeutic target in inflammatory bowel disease.     

Effect of Aloe vera gel extract on antioxidant enzymes and azoxymethane-induced oxidative stress in rats

The present work was undertaken with a view to study the effect of oral feeding of 2% Aloe vera gel extract (AGE) for 30 days on azoxymethane (AOM)-induced oxidative stress in rats. It was observed that AOM administration resulted in a significant increase in malondialdehyde and conjugated dienes, with reduction in hepatic glutathione (GSH), vitamin A and uric acid contents. AOM-induced reduction in hepatic GSH and uric acid was brought back to normal by AGE. There was a significant raise in hepatic catalase, superoxide dismutase and glucose-6-phosphate dehydrogenase (G-6-PD) activities as a result of feeding of the extract. Ingestion of the extract effected reduction in AOM-induced colonic GSH-peroxidase, G-6-PD and glutathione S-transferase and femur bone marrow micronuclei formation. Hence, it is suggested that Aloe vera gel extract possess the ability to reduce AOM- induced oxidative stress and toxicity in liver.     

Dual role of endogenous nitric oxide in development of dextran sodium sulfate-induced colitis in rats.

The role of nitric oxide (NO) in the etiology of ulcerative colitis is controversial with reports of the improvement and aggravation of colonic lesions by inducible NO synthase (iNOS) inhibitors. In the present study, we compared the effect of the selective iNOS inhibitor aminoguanidine and the nonselective NOS inhibitor N(G)-nitro-L-arginine methyl ester (L-NAME) on a dextran sulfate sodium (DSS)-induced model of colitis in rats. Experimental colitis was induced by a 3% DSS-solution added to drinking water for 7 days. Aminoguanidine (5 approximately 20 mg/kg) and L-NAME (10 mg/kg) were administered p.o. twice daily for the first 3 days, the last 3 days or all 6 days of DSS treatment. Body weight and severity of colitis (diarrhea, bloody feces) were observed over a period of 7 days. DSS treatment resulted in severe colonic lesions, accompanied by diarrhea, bloody feces, decrease of body weight and colon shortening. All of the parameters investigated improved significantly with aminoguanidine treatment at 20 mg/kg for 6 days or the last 3 days of DSS-treatment, but L-NAME did not significantly affect the colitis during these periods. When L-NAME or aminoguanidine was given in the first 3 days of DSS treatment, the colonic lesions were slightly aggravated by L-NAME but not affected by aminoguanidine. The expression of iNOS mRNA was observed from the 3(rd) day of DSS treatment. These results suggested that endogenous NO exerts a biphasic influence on DSS-induced colitis, depending on the NOS isoenzyme; a beneficial effect of NO derived from constitutive NOS and a detrimental effect of NO produced by iNOS in the development of colitis.     

Hepatoprotective effect of Aloe vera against cartap- and malathion-induced toxicity in Wistar rats

Exposure to mixture of pesticides in agricultural practices pose a serious threat to the nontarget animals. In present work, we have evaluated the synergistic effect of cartap and malathion on rat liver followed by impact of Aloe vera leaves aqueous extract, which is not known. The animals in eight groups were used; each containing six rats: Group 1 acted as a control, Group 2—control with A. vera leaves aqueous extract, Group 3—with cartap, Group 4—with malathion, Group 5—with mixture of cartap and malathion, Group 6—cartap with the pretreatment of A. vera leaf extract, Group 7—malathion with the pretreatment of A. vera leaf extract, Group 8—mixture of cartap and malathion with the pretreatment of A. vera leaf extract . The animals treated for 15 days were killed after 24hr of last treatment. The biochemical studies in the rat liver demonstrated significant perturbations in the levels of nonenzymatic (glutathione and malondialdehyde) and enzymatic (superoxide dismutase, catalase, and glutathione- S-transferase) antioxidative indices. The histopathological examination of liver revealed serious congestion in central vein and the disorganization of hepatic cords due to pesticide treatment. The administration of A. vera leaves aqueous extract was able to markedly protect rat liver from the pesticides-induced toxicity. The data indicated that pesticides were able to significantly induce oxidative stress which was substantially reduced by the application of plant extract .     

Protein carbonyl formation on mucosal proteins in vitro and in dextran sulfate-induced colitis.

Reactive oxygen and nitrogen species have been implicated as mediators of mucosal injury in inflammatory bowel disease, but few studies have investigated protein oxidation in the inflamed mucosa. In this study, protein carbonyl formation on colonic mucosal proteins from mice was investigated following in vitro exposure of homogenates to iron/ascorbate, hydrogen peroxide, hypochloric acid (HOCl), or nitric oxide (*NO). Total carbonyl content was measured spectrophotometrically by derivatization with dinitrophenylhydrazine (DNPH), and oxidation of component proteins within the tissue was examined by Western blotting for DNPH-derivatized proteins using anti-dinitrophenyl DNP antibodies. These results were compared with protein carbonyl formation found in the acutely inflamed mucosa from mice with colitis induced by dextran sulfate sodium (DSS) administered at 5% w/v in the drinking water for 7 d. In vitro, carbonyl formation was observed after exposure to iron/ascorbate, HOCl and *NO. Iron/ascorbate (20 microM/20 mM) exposure for 5 h increased carbonyl groups by 80%, particularly on proteins of 48, 75-100, 116, 131, and 142 kDa. Oxidation by 0.1 and 0.5 mM HOCl did not increase total carbonyl levels, but Western blotting revealed carbonyl formation on many proteins, particularly in the 49-95 kDa region. After exposure to 1-10 mM HOCl, total carbonyl levels were increased by 0.5 to 12 times control levels with extensive cross-linking and fragmentation of proteins rich in carbonyl groups observed by Western blotting. In mice with acute colitis induced by DSS, protein carbonyl content of the inflamed mucosa was not significantly different from control mucosa, (7.80 +/- 1.05 vs. 8.43 +/- 0.59 nmo/mg protein respectively, p = .16 n = 8, 10); however, Western blotting analysis indicated several proteins of molecular weight 48, 79, 95, and 131 kDa that exhibited increased carbonyl content in the inflamed mucosa. These proteins corresponded to those observed after in vitro oxidation of normal intestinal mucosa with iron/ ascorbate and HOCl, suggesting that both HOCl and metal ions may be involved in protein oxidation in DSS-induced colitis. Identification and further analysis of the mucosal proteins susceptible to carbonyl modification may lead to a better understanding of the contribution of oxidants to the colonic mucosa tissue injury in inflammatory bowel disease.     

The deficit in folate and vitamin B12 triggers liver macrovesicular steatosis and inflammation in rats with dextran sodium sulfate-induced colitis

The risks of nonalcoholic steatohepatitis (NASH) and deficiency in vitamin B12 and folate (methyl donor deficiency, MDD) are increased in inflammatory bowel disease (IBD). We investigated the influence of MDD on NASH in rats with DSS-induced colitis. Two-month-old male Wistar rats were subjected to MDD diet and/or ingestion of DSS and compared to control animals. We studied steatosis, inflammation, fibrosis, plasma levels of metabolic markers, cytokines and lipopolysaccharide, and inflammatory pathways in liver. MDD triggered a severe macrovesicular steatosis with inflammation in DSS animals that was not observed in animals subjected to DSS or MDD only. The macrovesicular steatosis was closely correlated to folate, vitamin B12, homocysteine plasma level and liver S-adenosyl methionine/S-adenosyl homocysteine (SAM/SAH) ratio. Liver inflammation was evidenced by activation of nuclear factor kappa B (NFκB) pathway and nuclear translocation of NFκB phospho-p65. MDD worsened the increase of interleukin 1-beta (IL-1β) and abolished the increase of IL10 produced by DSS colitis. It increased monocyte chemoattractant protein 1 (MCP-1). MDD triggers liver macrovesicular steatosis and inflammation through imbalanced expression of IL-1β vs. IL10 and increase of MCP-1 in DSS colitis. Our results suggest evaluating whether IBD patients with MDD and increase of MCP-1 are at higher risk of NASH.     

Effects of anthocyanin-rich tea "Sunrouge" on dextran sodium sulfate-induced colitis in mice

Sunrouge, an anthocyanin-rich tea, has similar levels of catechins as "Yabukita," the most popular green tea cultivar consumed in Japan. Green tea polyphenols (GTPs) have attracted interest due to their potent antioxidative activities combined with a lack of side effects in humans at normal consumption levels. However, we previously reported that high doses (0.5 and 1%) of dietary GTPs can result in deterioration of colitis and failed to prevent colon carcinogenesis in inflamed colons. In the present study, we determined the inhibitory effects of Sunrouge on colitis in dextran sodium sulfate (DSS)-treated and untreated control mice. Five-week-old female ICR mice were administered a single dose of Yabukita or Sunrouge (extracts in 1 mL distilled water) via a stomach tube for 3 weeks. After 1 week of treatment, the mice were divided into four groups (two Yabukita and two Sunrouge groups) and given drinking water with or without 3% DSS for 2 weeks, then they were euthanized. Those treated with DSS developed watery diarrhea and bloody stools, and showed body weight loss, spleen hypertrophy, and shortening of the colon, as well as deteriorations in survival rate, liver function, colon mucosal interleukin-1β level and expression of phase II detoxification enzyme mRNA. Sunrouge improved these DSS-induced symptoms, at least in part, whereas Yabukita showed either no effect or adverse effects in regard to some those parameters. It is suggested that the differences between Yabukita and Sunrouge on DSS-induced colitis might be due to the high levels of anthocyanins found in Sunrouge tea.     

Resveratrol abrogates adhesion molecules and protects against TNBS-induced ulcerative colitis in rats

Resveratrol, a polyphenol compound with anti-inflammatory properties, has been previously evaluated for its beneficial effects in several ulcerative colitis models. However, the current study elucidates the effect of resveratrol on adhesion molecules, as well as its antioxidant efficacy in a trinitrobenzene sulfonic acid (TNBS)-induced ulcerative-colitis model. Colitis was induced by rectal instillation of TNBS, followed by daily per os administration of either sulphasalazine (300?mg/kg) or resveratrol (2 and 10?mg/kg) for 7?days. Administration of resveratrol decreased the ulcerative area and colon mass index; these effects were further supported by the reduction in colon inflammation grades, as well as histolopathological changes, and reflected by the stalling of body mass loss. The anti-inflammatory effects of resveratrol were indicated by lowered myeloperoxidase activity, and by suppressing ICAM-1 and VCAM-1 levels in the colon and serum. In addition, it restored a reduced colonic nitric oxide level and reinstated its redox balance, as evidenced by the suppression of lipid peroxides and prevention of glutathione depletion. The anti-ulcerative effect of the higher dose of resveratrol was comparable with those of sulphasalazine. The study confirms the anti-ulcerative effect of resveratrol in TNBS-induced experimental colitis via reduction of neutrophil infiltration, inhibition of adhesive molecules, and restoration of the nitric oxide level, as well as the redox status.     

Protection against dextran sulfate sodium-induced colitis by microspheres of ellagic acid in rats

Ellagic acid (EA), a naturally occurring plant phenol, has the antioxidant and anti-inflammatory activities. In the present study, we examined the effect of EA contained in microspheres on the ulcerative colitis induced experimentally in rats by dextran sulfate sodium (DSS). Experimental colitis was induced in male Fisher 344 rats by daily treatment with 3% DSS solution in drinking water for 7 days. EA of microspheres (mcEA: 1 approximately 10 mg/kg as EA contents) was administered p.o. twice daily for 6 days. In a preliminary study, we found that these microsphere capsules, when administered p.o., are effectively dissolved in the proximal to the ileo-cecal junction and distributed to the terminal ileum and the colon. The ulceration area, colon length, and mucosal myeloperoxidase (MPO) activity as well as thiobarbituric acid-reactive substances (TBARS) were measured on 7th day after the onset of DSS treatment. The DSS treatment for 7 days caused severe mucosal lesions in the colon, accompanied with the increases of MPO activity and TBARS as well as the decreases of body weight gain and colon length. Administration of mcEA reduced the severity of DSS-induced colitis in a dose-dependent manner, and a significant effect was observed at 10 mg/kg, the ED50 being 2.3 mg/kg. This mcEA treatment also significantly mitigated changes in various biochemical parameters in the colonic mucosa induced by DSS. Although plain EA (without using microspheres) was also effective in reducing the severity of DSS-induced colitis, this effect was much less potent as compared with that of mcEA; the ED50 was about 15 times higher than that of mcEA. In addition, a significant effect on DSS-induced colitis was also obtained by intra-rectal administration of superoxide dismutase, an anti-oxidative agent. These results suggest that EA prevents the ulcerative colitis induced by DSS, probably by radical scavenging and/or anti-oxidative actions. The microspheres used in this study may be useful for delivering an orally administered drug specifically to the colon.     

Effect of Aloe vera polysaccharides on immunity and antioxidant activities in oral ulcer animal models

Aloe vera polysaccharides have traditionally been used in Asian cultures as medicinal plants to enhance immunity and reduce oxidative injury. The current investigation was conducted to examine the effects of A. vera polysaccharides on various in vivo parameters of innate immunity and antioxidant enzymes activities in oral ulcer animals. Forty wistar rats were randomly divided into the following 1 control group and 3 experimental groups (each group contained 10 rats). Rats in experimental groups were orally fed by A. vera polysaccharides. Rats in control group were orally fed by same volume of saline. The results showed that A. vera polysaccharides enhanced immunity activity and exerted antioxidant effects compared with vehicle controls. These results demonstrate, for the first time, that A. vera polysaccharides are effective in enhancing innate immunity and suppressing oxidative injury in oral ulcer animals.     

Effect of cinnamon essential oil on gut microbiota in the mouse model of dextran sodium sulfate-induced colitis

Increasing evidence has confirmed that the antimicrobial and anti-inflammatory effects of cinnamon essential oil (CEO) contribute to protection against inflammatory bowel disease (IBD). The dextran sodium sulfate (DSS)-induced colitis mouse model was established to investigate the correlation between the protective effects of CEO and the regulation of intestinal microflora. The symptoms of IBD were assessed by measuring the hemoglobin content, myeloperoxidase activity, histopathological observation, cytokines, and toll-like receptor (TLR4) expression. The alteration of the fecal microbiome composition was analyzed by 16S rRNA gene sequencing. The results indicated that the oral administration of CEO enriched with cinnamaldehyde effectively alleviated the development of DSS-induced colitis. In contrast to the inability of antibiotics to regulate flora imbalance, the mice fed with CEO had an improved diversity and richness of intestinal microbiota, and a modified community composition with a decrease in Helicobacter and Bacteroides and an increase in Bacteroidales_S24-7 family and short-chain fatty acids (SCFA)-producing bacteria (Alloprevotella and Lachnospiraceae_NK4A136_group). Moreover, the correlation analysis showed that TLR4 and tumor necrosis factor-α was positively correlated with Helicobacter, but inversely correlated with SCFA-producing bacteria. These findings indicated from a new perspective that the inhibitory effect of CEO on IBD was closely related to improving the intestinal flora imbalance.     

Antioxidant properties and PC12 cell protective effects of APS-1, a polysaccharide from Aloe vera var. chinensis

Through a combination of anion-exchange and repeated gel chromatographies, APS-1 was isolated from fresh leaves of Aloe vera L. var. chinensis (Haw.) Berger (an edible and medicinal plant widely cultivated and consumed in China) as a principal polysaccharide composed of mannose and glucose (ca. 18:5) with its molecular weight around 2.1 x 10(5). In a dose-dependent manner, APS-1 was demonstrated to be free radical scavenging in superoxide and hydroxyl radical assays, inhibitory to the copper-mediated oxidation of human low density lipoprotein (LDL), and protective against hydrogen peroxide (H(2)O(2))-induced lesion to rat PC12 cell (pheochromocytoma cell line). The result suggested that APS-1 could be of considerable preventive and therapeutic significance to some free radical associated health problems such as coronary heart ailments, Parkinson's and Alzheimer's diseases. Furthermore, the finding shed as well fresh light helpful for a better understanding of the health-benefiting potential of the edible plant consumed by the Chinese people for a couple of centuries.