Inosine reduces inflammation and improves survival in a murine model of colitis

Inosine, a naturally occurring purine formed from the breakdown of adenosine, has recently been shown to exert powerful anti-inflammatory effects both in vivo and in vitro. This study evaluated inosine as a potential therapy for colitis. Colitis was induced in mice by the administration of dextran sulfate sodium (DSS). Oral treatment with inosine was begun either before the onset of colitis or as a posttreatment once colitis was established. Evaluation of colon damage and inflammation was determined grossly (body wt, rectal bleeding), histologically, and biochemically (colon levels of MPO, MDA, and cytokines). DSS-induced colitis significantly increased inflammatory cell infiltration into the colon. DSS-induced colitis also increased colon levels of lipid peroxidation, cytokines, and chemokines. Inosine protected the colon from DSS-induced inflammatory cell infiltration and lipid peroxidation. Inosine also partially reduced these parameters in an experimental model of established colitis. Thus inosine treatment may be a potential therapy in colitis.     

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.     

Oxytocin ameliorates oxidative colonic inflammation by a neutrophil-dependent mechanism

Oxytocin (OT), a nonapeptide produced in the paraventricular and the supraoptical nuclei in the hypothalamus has a wide range of effects in the body. However, the role of OT on the gastrointestinal (GI) tract has to be settled. OT may participate in the regulation of motility, secretion, blood flow, cell turnover and release of neurotransmitters and/or peptides in the GI tract, possesses antisecretory and antiulcer effects, facilitates wound healing and is involved in the modulation of immune and inflammatory processes. The present work was conducted to assess the possible therapeutic effects of OT against the acetic acid-induced colonic injury in the rat. METHODS: Colitis was induced by intracolonic administration of acetic acid (5%) in Sprague-Dawley rats (200-250 g). Either saline or OT (0.5 mg/kg) was injected subcutaneously, immediately after the induction of colitis and repeated two times a day for 4 days. On the 4th day, rats were decapitated and distal 8 cm of the colon were removed for the macroscopic and microscopic damage scoring, determination of tissue wet weight index (WI), malondialdehyde (MDA) levels, an end product of lipid peroxidation; glutathione (GSH) levels, a key antioxidant; and myeloperoxidase (MPO) activity, as an indirect index of neutrophil infiltration. Colonic collagen content, as a fibrosis marker was also determined. Lactate dehydrogenase (LDH) and tumor necrosis factor-alpha (TNF-alpha) levels were assayed in serum samples. In the acetic acid-induced colitis, macroscopic and microscopic damage scores, WI, MDA and MPO levels were significantly increased, while GSH levels were decreased when compared to control group (p <0.05-<0.001). Treatment with OT abolished the colitis-induced elevations in damage scores, WI, MDA and MPO levels and restored the GSH levels (p <0.05-0.001). Similarly, acetic acid increased the collagen content of colonic tissues and OT-treatment reduced this value to the level of the control group. Serum LDH and TNF-alpha levels were also elevated in the acetic acid-induced colitis group as compared to control group, while this increase was significantly decreased by OT treatment. The results suggest that OT, which improves the antioxidative state of the colonic tissue and ameliorates oxidative colonic injury via a neutrophil-dependent mechanism, requires further investigation as a potential therapeutic agent in colonic inflammation.     

Investigation of protein oxidation and lipid peroxidation in patients with rheumatoid arthritis

We aimed to determine the importance of neutrophil activation and the source of oxidative stress in the pathogenesis of rheumatoid arthritis (RA) by quantification of advanced oxidation protein products (AOPP) and total thiol levels as markers of oxidative protein damage, malondialdehyde (MDA) levels as a marker of lipid peroxidation and myeloperoxidase (MPO) activity as a marker of neutrophil activation in patients with RA. Fifty-seven rheumatoid arthritis patients were included in the study and sub-grouped according to disease activity (active, n = 31; inactive, n = 26) and compared with healthy controls (n = 25). Serum MPO activity, AOPP, MDA, and thiol levels were measured by an enzymic spectrophotometric method. Serum MPO activity (p < 0.001), AOPP (p < 0.001), MDA (p < 0.001) and levels of thiol (p < 0.002), were higher in the patient group than the controls. Active and inactive RA groups were compared with the control group and there were significant differences between each parameter. MPO activity, AOPP, MDA and thiol levels were significantly higher in both active and inactive RA patients than the controls. On the other hand, when a comparison was made between active and the inactive stage, a statistically significant difference was present only in MDA (p < 0.05) and AOPP levels (p < 0.05). There was also a significant positive correlation between all parameters. These data strongly suggest that neutrophils, which constitute the most important source of chlorinated oxidants due to their high MPO content, may be involved in serum AOPP formation and therefore the production of a novel class of pro-inflammatory mediators of oxidative stress in RA patients and that protein oxidation could play an important role in the pathogenesis of RA as does lipid peroxidation.     

Part I: pathogenetic role of peroxynitrite in the development of diabetes and diabetic vascular complications: studies with FP15, a novel potent peroxynitrite decomposition catalyst

BACKGROUND: Peroxynitrite is a cytotoxic oxidant formed from nitric oxide (NO) and superoxide. Tyrosine nitration, a footprint of peroxynitrite, has been demonstrated in the pancreatic islets as well as in the cardiovascular system of diabetic subjects. Delineation of the pathogenetic role of peroxynitrite in disease conditions requires the use of potent, in vivo active peroxynitrite decomposition catalysts. The aim of the current work was to produce a potent peroxynitrite decomposition catalyst and to test its effects in rodent models of diabetes and its complications. METHODS: FP15 was synthesized and analyzed using standard chemical methods. Diabetes was triggered by the administration of streptozotocin. Tyrosine nitration was measured immunohistochemically. Cardiovascular and vascular measurements were conducted according to standard physiologic methods. RESULTS: FP15, a potent porphyrinic peroxynitrite decomposition catalyst, potently inhibited tyrosine nitration and peroxynitrite-induced cytotoxicity in vitro and in vivo. FP15 treatment (3-10 mg/kg/d) dose dependently and reduced the incidence and severity of diabetes mellitus in rats subjected to multiple low doses of streptozotocin, as well as in nonobese mice developing spontaneous autoimmune diabetes. Furthermore, treatment with FP15 protected against the development of vascular dysfunction (loss of endothelium-dependent relaxations) and the cardiac dysfunction (loss of myocardial contractility) in diabetic mice. FP15 treatment reduced tyrosine nitration in the diabetic pancreatic islets. CONCLUSIONS: The current results demonstrate the importance of endogenous peroxynitrite generation in the pathogenesis of autoimmune diabetes and diabetic cardiovascular complications. Peroxynitrite decomposition catalysts may be of therapeutic utility in diabetes and other pathophysiologic conditions.     

The detrimental effect of nitric oxide on tissue is associated with inflammatory events in the vascular endothelium and neutrophils in mice with dextran sodium sulfate-induced colitis

Abstract

Nitric oxide (NO) is thought to be a key molecule in the progression of ulcerative colitis and experimental colitis induced by dextran sodium sulfate (DSS). However, the detrimental effect of DSS-induced NO production on the colonic mucosa is incompletely understood. Increases in the expression of adhesion molecules in the vascular endothelium and activated neutrophils (thereby releasing injurious molecules such as reactive oxygen species) are reportedly associated with the pathogenesis of DSS-induced colitis. We investigated if the detrimental effect of NO production on the colonic mucosa was attributable to the activation of neutrophil infiltration by NO in mice with DSS-induced colitis. NO₂^?/NO₃^? content in the middle and distal colon was increased on days 5 and 7, but alterations in the proximal colon were not observed. Myeloperoxidase (MPO) activity and expression of P-selectin and intercellular adhesion molecule-1 (ICAM-1) were significantly increased in the entire colon, whereas TNF-α levels were significantly increased only in the middle and distal colon on day 7. The pathology of colitis and increases in colonic MPO activity, P-selectin, ICAM-1, and TNF-α levels were suppressed by the inducible NO synthase (iNOS)-specific inhibitor aminoguanidine and NO scavenger c-PTIO, whereas all but TNF-α levels were increased by the non-specific NOS inhibitor L-NAME. These findings suggest that iNOS-derived NO increases TNF-α levels in the middle and distal colon and increased TNF-α levels induce expression of P-selectin and ICAM-1, thereby promoting the infiltration of activated neutrophils, which leads to damage to colonic tissue.     

肾上腺髓质素对缺血再灌注后肾功能的保护

目的:探讨肾上腺髓质素(Adrenomedullin,ADM)对缺血再灌注后肾功能的保护作用。方法:在注射外源性ADM蛋白后,建立急性缺血再灌注肾损伤模型,观察ADM对肾功能和氧化损伤指标肌酐(Creatinine,Cr)、尿素氮(Blood Urea Nitrogen,BUN)、髓过氧化物酶(Myeloperoxidase,MPO)、丙二醛(Malondialdehyde,MDA)、超氧化物歧化酶(Superoxide Dismutase,SOD)影响。结果:与I组比较,II组的Cr、BUN、MPO、MDA大幅升高(P0.05),表明急性肾损伤造模成功。与II相比,III组BUN、MPO、MDA明显下降(P0.05),表现出一定的保护作用。结论:ADM对缺血再灌注损伤后的肾功能具有一定的保护作用,其机制可能与减少中性粒细胞浸润,抑制膜脂质的氧化,促进微血管重生修复有关。     

Nerolidol,a sesquiterpene,attenuates oxidative stress and inflammation in acetic acid-induced colitis in rats

Targeting oxidative stress and inflammation by novel dietary compounds of natural origin convincingly appears to be one of the most important therapeutic strategies to keep inflammatory bowel diseases (IBD) such as ulcerative colitis disease in remission. It is imperative to investigate naturally occuring plant-derived dietary phytochemicals that are receiving attention for their therapeutic benefits to overcome the debilitating conditions of IBD. In the present study, the effect of nerolidol (NRD), a monocyclic sesquiterpene found in German Chamomile tea, was investigated in acetic acid-induced colitis model in Wistar rats. NRD was orally administered at a dose of 50 mg/kg/day either for 3 days before or 30 min after induction of IBD for 7 days, after intrarectal administration of acetic acid. The body weight, macroscopic, and microscopic analyses of the colon in different experimental groups were observed on days 0, 2, 4, and 7. Acetic acid caused significant reduction in body weight and induced macroscopic and microscopic ulcer along with a significant decline of antioxidants, concomitant to increased malondialdehyde (MDA), a marker of lipid peroxidation, and myeloperoxidase (MPO) activity, a marker of neutrophil activation. Treatment with NRD significantly improved IBD-induced reduction in body weight, improved histology, inhibited MDA formation, and restored antioxidants along with reduced MPO activity. Acetic acid also induced the release of pro-inflammatory cytokines and increased calprotectin, released by neutrophils under inflammatory conditions. NRD treatment significantly reduced calprotectin and pro-inflammatory cytokines. NRD treatment showed potential to improve disease activity and inhibit oxidative stress, lipid peroxidation, and inflammation along with histological preservation of the colon tissues.

     

Amelioration of dextran sulfate sodium-induced colitis in mice by oral administration of beta-caryophyllene, a sesquiterpene

beta-Caryophyllene (BCP), a naturally occurring plant sesquiterpene, was examined for anti-inflammatory activity in a mouse model of experimental colitis induced by dextran sulfate sodium (DSS). Colitis was induced by exposing male BALB/c mice to 5% DSS in drinking water for 7 days. BCP in doses of 30 and 300 mg/kg was administered orally once a day, beginning concurrently with exposure to DSS. The body weight and colon length were measured, and histological damage and myeloperoxidase (MPO) activity as well as inflammatory cytokines were assessed in both serum and colonic tissue after 7 days of treatment with DSS. The DSS treatment damaged the colonic tissue, increased MPO activity and inflammatory cytokines, lowered the body weight, and shortened the length of the colon. Oral administration of BCP at 300 mg/kg significantly suppressed the shortening of colon length and slightly offset the loss of body weight. BCP treatment (300 mg/kg) also significantly reduced the inflammation of colon and reversed the increase in MPO activity that had been induced by exposure to DSS. Further, BCP significantly suppressed the serum level of IL-6 protein (a 55% reduction) as well as the level of IL-6 mRNA in the tissue. These results demonstrate that BCP ameliorates DSS-induced experimental colitis, and may be useful in the prevention and treatment of colitis.     

Myeloperoxidase deficiency attenuates systemic and dietary iron-induced adverse effects

Iron deficiency is routinely treated with oral or systemic iron supplements, which are highly reactive and could induce oxidative stress via augmenting the activity of proinflammatory enzyme myeloperoxidase (MPO). To investigate the extent to which MPO is involved in iron-induced toxicity, acute (24 h) iron toxicity was induced by intraperitoneal administration of FeSO₄ (25 mg/kg body weight) to MPO-deficient (MpoKO) mice and their wild-type (WT) littermates. Acute iron toxicity was also assessed in WT mice pretreated with an MPO inhibitor, 4-aminobenzoic acid hydrazide. Systemic iron administration up-regulated circulating MPO and neutrophil elastase and elevated systemic inflammatory and organ damage markers in WT mice. However, genetic deletion of MPO or its inhibition significantly reduced iron-induced organ damage and systemic inflammatory responses. In contrast to the acute model, 8 weeks of 2% carbonyl iron diet feeding to WT mice did not change the levels of circulating MPO and neutrophil elastase but promoted their accumulation in the liver. Even though both MpoKO and WT mice displayed similar levels of diet-induced hyperferremia, MpoKO mice showed significantly reduced inflammatory response and oxidative stress than the WT mice. In addition, WT bone-marrow-derived neutrophils (BMDN) generated more reactive oxygen species than MPO-deficient BMDN upon iron stimulation. Altogether, genetic deficiency or pharmacologic inhibition of MPO substantially attenuated acute and chronic iron-induced toxicity. Our results suggest that targeting MPO during iron supplementation is a promising approach to reduce iron-induced toxicity/side effects in vulnerable population.     

Green tea polyphenol extract attenuates colon injury induced by experimental colitis

Inflammatory bowel disease (IBD) is characterised by oxidative and nitrosative stress, leukocyte infiltration, and up-regulation of intercellular adhesion molecule 1 (ICAM-1) expression in the colon. The aim of the present study was to examine the effects of green tea extract in rats subjected to experimental colitis induced by intracolonic instillation of dinitrobenzene sulphonic acid (DNBS). At 4 days after DNBS administration the rats were sacrificed. Treatment with green tea extract significantly attenuated diarrhoea and loss of body weight. This was associated with a remarkable amelioration of the disruption of the colonic architecture, significant reduction of colonic myeloperoxidase (MPO) and tumor necrosis factor-alpha (TNF-alpha) production. Green tea extract also reduced the appearance of nitrotyrosine immunoreactivity in the colon and reduced the up-regulation of ICAM-1.     

Antioxidant properties of mesenchymal stem cells against oxidative stress in a murine model of colitis

Objective

To investigate the effects of oxidative stress injury in dextran sulfate sodium (DSS)-induced colitis in mice treated with mesenchymal stem cells (MSC).

Results

Mice exposed to oral administration of 2% DSS over 7 days presented a high disease activity index and an intense colonic inflammation. Systemic infusion of MSC protected from severe colitis, reducing weight loss and diarrhea while lowering the infiltration of inflammatory cells. Moreover, toxic colitis injury increased oxidative stress. Administration of DSS decreased reduced glutathione (GSH) and superoxide dismutase (SOD) activity, and increased thiobarbituric acid-reactive substances levels in the colon. No alteration was found in catalase (CAT) and glutathione peroxidase (GPx) activity. Otherwise, MSC transplantation was able to prevent the decrease of GSH levels and SOD activity suggestive of an antioxidant property of MSC.

Conclusion

The oxidative stress is a pathomechanism underlying the pathophysiology of colitis and MSC play an important role in preventing the impairment of antioxidants defenses in inflamed colon.

     

The importance of oxidative stress in patients with chronic renal failure whose hypertension is treated with peritoneal dialysis

Increased oxidative stress is a well-known phenomenon in dialysis patients. However, the contribution of hypertension to the oxidative stress in peritoneal dialysis patients has not yet been assessed. The present study aimed to investigate if hypertension had an additional effect on oxidative stress in peritoneal dialysis patients. A total of 50 patients treated with peritoneal dialysis were divided into two groups: The patients with mean of last three blood pressure results as 135/90 mmHg and above were considered hypertensive, the patients with lower blood pressure were considered normotensive. The control group included 25 healthy individuals. Serum malondialdehyde (MDA), advanced oxidation protein product (AOPP), myeloperoxidase (MPO), catalase (CAT) and glutathione peroxidase (GSH-Px) levels were measured in all groups. MDA level, an indicator of lipid peroxidation, was significantly higher in the hypertensive group compared to the control group, while the increase in the normotensive group was not significant. However, the difference between the hypertensive and normotensive groups was significant. The levels of AOPP, an indicator of protein oxidation level, and MPO, an indicator of neutrophil activation, were not different between the groups, while the activities of antioxidant CAT and GSH-Px decreased in both normotensive and hypertensive groups compared to the control group, and there was no significant difference between the patient groups. This study shows that both normotensive and hypertensive peritoneal dialysis patients have increased-oxidative stress and decreased antioxidant levels and hypertension might have an additional effect on oxidative stress by increasing MDA level in peritoneal dialysis patients.     

Deficient Production of Reactive Oxygen Species Leads to Severe Chronic DSS-Induced Colitis in Ncf1/p47phox-Mutant Mice

Background

Colitis is a common clinical complication in chronic granulomatous disease (CGD), a primary immunodeficiency caused by impaired oxidative burst. Existing experimental data from NADPH-oxidase knockout mice propose contradictory roles for the involvement of reactive oxygen species in colitis chronicity and severity. Since genetically controlled mice with a point-mutation in the Ncf1 gene are susceptible to chronic inflammation and autoimmunity, we tested whether they presented increased predisposition to develop chronic colitis.

Methods

Colitis was induced in Ncf1-mutant and wild-_type mice by a 1^st 7-days cycle of dextran sulfate sodium (DSS), intercalated by a 7-days resting period followed by a 2^nd 7-days DSS-cycle. Cytokines were quantified locally in the colon inflammatory infiltrates and in the serum. Leukocyte infiltration and morphological alterations of the colon mucosa were assessed by immunohistochemistry.

Results

Clinical scores demonstrated a more severe colitis in Ncf1-mutant mice than controls, with no recovery during the resting period and a severe chronic colitis after the 2^nd cycle, confirmed by histopathology and presence of infiltrating neutrophils, macrophages, plasmocytes and lymphocytes in the colon. Severe colitis was mediated by increased local expression of cytokines (IL-6, IL-10, TNF-α, IFN-γ and IL-17A) and phosphorylation of Leucine-rich repeat kinase 2 (LRRK2). Serological cytokine titers of those inflammatory cytokines were more elevated in Ncf1-mutant than control mice, and were accompanied by systemic changes in functional subsets of monocytes, CD4⁺T and B cells.

Conclusion

This suggests that an ineffective oxidative burst leads to severe chronic colitis through local accumulation of peroxynitrites, pro-inflammatory cytokines and lymphocytes and systemic immune deregulation similar to CGD.     

Anthocyanin-containing purple potatoes ameliorate DSS-induced colitis in mice

Ulcerative colitis (UC), a major form of inflammatory bowel disease (IBD), is on the rise worldwide. Approximately three million people suffer from IBD in the United States alone, but the current therapeutic options (e.g., corticosteroids) come with adverse side effects including reduced ability to fight infections. Thus, there is a critical need for developing effective, safe and evidence-based food products with anti-inflammatory activity. This study evaluated the antiinflammatory potential of purple-fleshed potato using a dextran sodium sulfate (DSS) murine model of colitis. Mice were randomly assigned to control (AIN-93G diet), P15 (15% purple-fleshed potato diet) and P25 (25% purple-fleshed potato diet) groups. Colitis was induced by 2% DSS administration in drinking water for six days. The results indicated that purple-fleshed potato supplementation suppressed the DSS-induced reduction in body weight and colon length as well as the increase in spleen and liver weights. P15 and P25 diets suppressed the elevation in the intestinal permeability, colonic MPO activity, mRNA expression and protein levels of pro-inflammatory interleukins IL-6 and IL-17, the relative abundance of specific pathogenic bacteria such as Enterobacteriaceae, Escherichia coli (E. coli) and pks⁺ E. coli, and the increased flagellin levels induced by DSS treatment. P25 alone suppressed the elevated systemic MPO levels in DSS-exposed mice, and elevated the relative abundance of Akkermansia muciniphila (A. muciniphila) as well as attenuated colonic mRNA expression level of IL-17 and the protein levels of IL-6 and IL-1β. Therefore, the purple-fleshed potato has the potential to aid in the amelioration of UC symptoms.     

Dextran sulfate sodium-induced ulcerative colitis leads to increased hematopoiesis and induces both local as well as systemic genotoxicity in mice

Ulcerative colitis is a chronic gastrointestinal disorder eliciting the risk of colorectal cancer, the third most common malignancy in humans. The present study was aimed to characterize dextran sulfate sodium-induced ulcerative colitis and to elucidate its influence on the bone marrow cell proliferation and the subsequent stimulation of the systemic genotoxicity in mice. Experimental colitis was induced in Swiss mice using 3% (w/v) dextran sulfate sodium in drinking water. The severity of colitis was assessed on the basis of clinical signs, colon length, oxidative stress parameters, various pro-inflammatory markers, histopathological evaluation and immunohistochemical staining of 8-oxo-7,8-dihydro-2'-deoxyguanosine in the colon of dextran sulfate sodium treated mice. Further, assessment of genotoxicity was carried out using alkaline and modified comet assays in the colon and lymphocytes and micronucleus assay in the peripheral blood of mice. For the evaluation of inflammation-induced cell proliferation in the bone marrow, proliferating cell nuclear antigen immunostaining was carried out in the bone marrow of mice. Dextran sulfate sodium induced severe colitis as evident from the elevated disease activity index, reduced colon length, increased oxidative stress, histological abnormalities and oxidative DNA damage in the colon of mice. Moreover, colitis-induced elevated prostaglandin-E2 level in the plasma of dextran sulfate sodium treated mice stimulated the cell proliferation in the bone marrow, which further triggered colitis-induced DNA damage in the peripheral blood of mice.     

Role of interleukin-6 in a non-septic shock model induced by zymosan.

In the present study, we used IL-6 knock-out mice (IL-6KO) to evaluate a possible role of IL-6 in the pathogenesis of non-septic shock induced by peritoneal injection of zymosan. A severe inflammatory response characterized by peritoneal exudation, high peritoneal levels of nitrate/nitrite, and leukocyte infiltration into peritoneal exudate was induced by zymosan administration in wild-type control (WT) mice. This inflammatory process coincided with the damage to the lung and small intestine, as assessed by histological examination. Lung, small intestine and liver myeloperoxidase (MPO) activity, indicative of neutrophil infiltration and lipid peroxidation, were significantly increased in zymosan-treated WT mice. Peritoneal administration of zymosan in the WT mice also induced a significant increase in the plasma levels of nitrite/nitrate and in the levels of peroxynitrite, 18 hours after zymosan challenge. Immunohistochemical examination demonstrated a marked increase in the immunoreactivity to nitrotyrosine in the lung of zymosan-treated WT mice. Zymosan-treated IL-6KO showed significantly decreased mortality and inhibition of the development of peritonitis. In addition, IL-6KO mice showed significant protection from the development of organ failure, since tissue injury and MPO was reduced in the lung, small intestine and liver. Furthermore, a significant reduction of suppression of mitochondrial respiration, DNA strand breakage and reduction of cellular levels of NAD+ was observed in ex vivo macrophages harvested from the peritoneal cavity of IL-6KO mice subjected to zymosan-induced non-septic shock. In vivo treatment with anti-IL-6 (5,000 ng/day per mouse, 24 and 1 hour before zymosan administration) significantly reduced the inflammatory process. Taken together, the present study clearly demonstrates that IL-6 exerts a role in zymosan-induced non-septic shock.     

Effects of antioxidant therapy on leukocyte myeloperoxidase and Cu/Zn-superoxide dismutase and plasma malondialdehyde levels in experimental colitis

The aim of the present study was to evaluate the effects of N-acetylcysteine (NAC) and L-carnitine (LCAR) supplementations on polymorphonuclear leukocytes myeloperoxidase (MPO) and Cu/Zn-superoxide dismutase (Cu/Zn-SOD) and plasma malondialdehyde (MDA) in acetic acid (AA)-induced ulcerative colitis model. The mean polymorphonuclear leukocyte MPO and Cu/Zn-SOD activity was significantly higher in the colitis group than in the control group. Both NAC and LCAR pretreatment markedly decreased MPO and Cu/Zn-SOD activity compared to colitis group. AA administration significantly increased the levels of plasma MDA in comparison with controls. However, NAC and LCAR administration to the AA-treated rats significantly reduced the MDA levels compared to colitis group. In conclusion NAC and LCAR could be beneficial agents in restoring the circulating proinflammatory mediators.     

On the benefit of whey-cultured Lactobacillus casei in murine colitis

The objective of this study was to examine the prophylactic and therapeutic effect of whey-cultured Lactobacillus casei (L. casei) in a murine model of colitis. Colitis was induced by intracolonic administration of a mixture of 2,4,6-trinitrobenzenesulphonic acid (TNBS)/absolute ethanol in male Wistar rats. Animals were divided into 5 groups including sham (normal group), control (vehicle-treated), positive control (dexamethasone 1 mg/kg/day, orally), prevention (10(8) cfu L. casei/day, orally, 14 days before induction of colitis), and treatment (10(8) cfu L. casei/day, orally, 14 days after induction of colitis). After 14-days treatment, the animals were sacrificed on the day 15. Distal colons were removed for examining histological and biochemical assays. Biomarkers including TNF-α, myeloperoxidase (MPO), and lipid peroxidation (LPO) were measured in the homogenate of colon. Results indicated an apparent improvement in colon histopathology scores, TNF-α, MPO, and LPO in the treatment group, whereas prevention group did not demonstrate positive efficacy in prevention of colonic damage. It is concluded that L. casei grown in whey culture is very effective in ameliorating both biochemical and histopathological markers of colitis if used post induction of colitis but not if used before induction of colitis. The difference between effects of L. casei when used pre-colitis and post-colitis confirms its mechanism of action as an anti toxic stress agent. Further studies should be made in IBD patients.