Effect of Iron Supplementation on Oxidative Stress and Intestinal Inflammation in Rats with Acute Colitis

In this study, we investigated the effect of intraperitoneal iron dextran (100mg/100 g body weight) on oxidative stress and intestinal inflammation in rats with acute colitis induced by 5% dextran sulfate sodium. In both colitis and healthy animals, disease activity index, crypt and inflammatory scores, colon length, plasma and colonic lipid peroxides, and plasma vitamins E, C, and retinol were assessed. The results showed that iron-supplemented groups had moderate iron deposition in the colonic submucosa and lamina propria. In the colitis group supplemented with iron, colon length was significantly shorter; disease activity index, crypt, and inflammatory scores and colonic lipid peroxides were significantly higher; and plasma -tocopherol was significantly lower compared to the colitis group without iron supplementation. There was no intestinal inflammation and no significant increase in colonic lipid peroxides in healthy rats supplemented with iron. In conclusion, iron injection resulted in an increased oxidative stress and intestinal inflammation in rats with colitis but not in healthy rats.     

Iron Supplementation May Aggravate Inflammatory Status of Colitis in a Rat Model

Iron supplementation is one of the principal therapies in inflammatory bowel disease. Iron is a major prooxidative agent; therefore therapeutic iron as well as heme iron from chronic mucosal bleeding can increase the iron-mediated oxidative stress in colitis by facilitating the Fenton reaction, namely production of hydroxyl radicals. In the present study colitis was induced in the iodoacetamide rat model. Forty male Whistar rats were divided into four groups, each group receiving a different diet regimen in parallel with colitis induction: Malondialdehyde was measured to assess the degree of tissue oxidative stress. There were microscopic changes, and significantly more severe colitis was seen in colonic biopsies when iron was supplemented. It was concluded that iron supplementation can amplify the inflammatory response and enhance the subsequent mucosal damage in a rat model of colitis. We suggest that the resultant oxidative stress generated by iron supplementation leads to the extension and propagation of crypt abscesses.     

Effect of aminophenols (5-ASA and 4-ASA) on colonic interleukin-1 generation.

The effect of 5-ASA and 4-ASA, drugs used for the treatment of inflammatory bowel disease, on modulation of experimental colitis and on colonic generation of interleukin-1 was evaluated. Three weeks of treatment with 5-ASA or 4-ASA (50 micrograms/kg) and one week of treatment with 5-ASA significantly decreased colonic interleukin-1 generation and the extent and severity of inflammation in a rat model of colitis induced by trinitrobenzene sulphonic acid. Colonic biopsies were obtained from patients with active ulcerative colitis and organ cultured 24 hours in the absence or presence of the following drugs: sulphasalazine, sulphapyridine, 5-ASA and 4-ASA (25-100 micrograms/ml). Interleukin-1 content in tissue cultured in the presence of 5-ASA (100 micrograms/ml) was two-thirds of its content in tissue cultured in drug free medium and its release into the medium was decreased by 50%. Sulphasalazine 50 micrograms/ml significantly decreased by 33% the tissue content but did not affect interleukin-1 release and a higher dose was not more effective. Sulphapyridine and 4-ASA in doses up to 100 micrograms/ml did not affect either interleukin-1 colonic content or its release into the culture medium. We conclude that pharmacological suppression of colonic interleukin-1 generation may be one, although not the sole mechanism to explain the therapeutic efficacy of 5-ASA in the treatment of inflammatory bowel disease.     

Effects of natural free radical scavengers on peripheral nerve and neurovascular function in diabetic rats

Summary Increased generation of reactive oxygen species, coupled with impaired endogenous scavenging mechanisms, plays a prominent role in the aetiology of neurovascular abnormalities in experimental diabetes mellitus. We examined the efficacy of the natural anti-oxidants vitamins C, E and -carotene in preventing nerve conduction and nutritive blood flow deficits in streptozotocin-diabetic rats. One month of diabetes caused a 19.1% reduction in sciatic motor conduction velocity (p<0.001). This was approximately prevented 80–90% by high-dose (1000 mg · kg^–1 · day^–1) vitamin E and -carotene treatments (p<0.001). Vitamin C had lesser effects; the maximum protection found for motor conduction velocity was 36% using a dose of 150 mg · kg^–1 · day^–1 (p<0.001). High dose (500 mg · kg^–1 · day^–1) vitamin C had a lesser effect on conduction than intermediate doses. Joint vitamin C and lower dose (500 mg · kg^–1 · day^–1) vitamin E treatment had a predominantly additive preventive effect against nerve dysfunction. Resistance to hypoxic conduction failure for sciatic nerve in vitro was markedly increased by diabetes and this remained relatively unaffected by treatment. Sciatic nutritive endoneurial blood flow, measured using microelectrode polarography and hydrogen clearance, was reduced 46.1% by 1 month of diabetes (p<0.001). This was prevented to the extent of 87%, 36% and 98% by vitamins E, C and -carotene, respectively (p<0.01). These data emphasize the role of oxidative stress in the development of early neurovascular changes in experimental diabetes and show that naturally available scavengers have a neuroprotective action.Abbreviations NCV Nerve conduction velocity - NO nitric oxide - ROS reactive oxygen species     

Effects of iron deprivation or chelation on DNA damage in experimental colitis

Background and aims In inflammatory bowel diseases iron contributes to the formation of DNA adducts through the production of hydroxyl radicals. The aim of our study was to evaluate the effects of dietary or pharmacological iron deprivation in an experimental model of colitis in the rat and its potential protective effect against DNA damage.Methods Colitis was induced in rats by intracolonic instillation of dinitrobenzene sulphonic acid. Rats were assigned to an iron-deprived diet or to desferrioxamine preceding the induction of colitis. The severity of colitis was assessed by the presence of bloody diarrhea, colonic macroscopic damage score, body-weight variations and the amount of DNA colonic adducts. Hepatic and colonic iron concentrations were measured.Results Treated rats experienced less diarrhea and did not lose weight in comparison to untreated animals. The macroscopic damage score was significantly reduced in the iron-deprived diet for the 5-week group (P=0.03). Liver and colonic iron levels were significantly more reduced in the iron-deprived groups than in the standard diet group (P<0.03 and P<0.01 after a 3- and 5-week iron-deprived diet, respectively). DNA adduct formation was significantly reduced in the groups deprived of iron for 5 weeks (P<0.001) or treated with desferrioxamine (P<0.01).Conclusions The degree of colitis caused by DNBS is macroscopically improved by dietary iron deprivation and to a lesser extent by pharmacological chelation; genomic damage is reduced by dietary iron deprivation or chelation, and this may have clinical implications on cancer prevention.M. Barollo and R. DIncà contributed equally to this paper     

Detection of allelic loss within the β1-interferon gene in childhood acute lymphoblastic leukemia using differential PCR

Summary Deletion of the short arm of chromosome 9p involving the 1-interferon (IFN) gene has been implicated in the process of malignant transformation in lymphomas and acute lymphoblastic leukemias. Since cytogenetic analysis is frequently unsuccessful in clinical samples, we used a recently described differential PCR technique to detect losses within the 1-IFN gene in 86 acute leukemias. Using differential PCR, no 1-IFN deletion was detected in 44 acute myeloid leukemia (AML) and eight control samples. However, five of 42 acute lymphoblastic leukemia (ALL) probes (12%) exhibited loss of the 1-IFN gene (three common ALL, two T-ALL). Cytogenetic analysis was performed independently in three of these five cases and revealed abnormalities of chromosome 9p in two samples. Two of five T-ALL cases exhibited a loss within the 1-IFN gene, compared with 3/29 c-ALLs, suggesting a predominance of IFN gene loss in T-ALLs. These data indicate that PCR can be used for rapid detection of gene dosage phenomena in clinical leukemia samples.     

Rebamipide Enema is Effective for Treatment of Experimental Dextran Sulfate Sodium Induced Colitis in Rats

We investigated therapeutic efficacy of rebamipide using dextran sulfate sodium (DSS) induced colitis model in rats. Three percent DSS solution was given to rats for 9 days. After that, we evaluated the drug efficacy on colitis sustained with continuous drinking of 1% DSS. Twice-daily treatment with 0.3% or 1% rebamipide for 14 days significantly ameliorated the stool abnormality in the colitis model, preferentially suppressed hematochezia. The colonic mucosal lesion, determined by Alcian blue staining on day 24, was significantly reduced by rebamipide enema in a dose-dependent manner. Either rebamipide or 5-aminosalycilic acid (5-ASA) enema treated once daily significantly ameliorated colitis. The minimum effective dose of rebamipide was 0.3% in once-daily treatment, and that of 5-ASA was 10%. In a mechanistic study, the epithelial cell sheet formation of the T84 colon cancer cell was measured as an increase in generation of trans-epithelial electrical resistance in vitro. Rebamipide accelerated the increase, while 5-ASA conversely suppressed it. These results suggest that rebamipide enema is effective for treatment of experimental ulcerative colitis (UC).     

Effect of T-cell receptor VΒ-specific monoclonal antibodies on cyclophosphamide-induced diabetes mellitus in non-obese diabetic mice

Summary The expression of specific T-cell receptor gene segments by T lymphocytes appears to be critically important for the induction of several experimental autoimmune diseases mediated by these cells. We examined whether this situation also applied to non-obese diabetic mice by using various T-cell receptor V-specific monoclonal antibodies. No significant age- or sex-related differences were observed in V usage by peripheral and splenic T lymphocytes. CD8⁺ T lymphocytes among the islet-derived mononuclear cells isolated from 20-week-old female non-obese diabetic mice showed heterogeneity of their V gene usage. In order to examine the role of T lymphocyte subsets expressing specific T-cell receptor V gene segments in the development of diabetes mellitus, T-cell receptor V-specific monoclonal antibodies were administered to 10-week-old male non-obese diabetic mice treated with cyclophosphamide. None of the antibodies used could significantly diminish the incidence of cyclophosphamide-induced diabetes and the severity of insulitis [anti-V3 (11 of 22 mice became diabetic, 50%), anti-V5 (9 of 14, 64%), anti-V8 (9 of 21, 43%), anti-V11 (12 of 23, 52%), anti-V14 (7 of 12, 58%), and anti-V5 + anti-V11 (6 of 12, 50%)] when compared with control mice (12 of 21, 57%). In addition, there were no significant differences in T-cell receptor V usage between diabetic and non-diabetic cyclophosphamide-treated mice. These results suggest that five T-lymphocyte subsets expressing different T-cell receptor V gene segments, considered to be candidates involved in the pathogenesis of autoimmune diabetes, do not individually contribute to the development of cyclophosphamide-induced diabetes in non-obese diabetic mice.     

Comparison of mRNA contents of interleukin-1Β and nitric oxide synthase in pancreatic islets isolated from female and male nonobese diabetic mice

Summary Interleukin-1 (IL-1) has been suggested to mediate beta-cell destruction in insulin-dependent diabetes mellitus (IDDM) by inducing nitric oxide production. In this study, we assessed the levels of IL-1 and the inducible form of nitric oxide synthase (iNOS), using a semi-quantitative polymerase chain reaction assay, and performed determinations of nitrite accumulation and IL-1 bioactivity, on pancreatic islets isolated from 5- and 16-week-old female and male nonobese diabetic (NOD) mice and from nondiabetes prone NMRI mice. NOD mouse islets contained notable amounts of IL-1 mRNA. At 5 weeks of age, but not at 16 weeks, the values were higher in islets isolated from NOD females compared to males. The IL-1 bioactivity showed differences roughly reflecting the mRNA levels in the NOD mouse islets. In the NMRI mouse islets the IL-1 bioactivity was very low. The expression of iNOS mRNA increased in both male and female islets between 5 and 16 weeks of age. Immunocytochemistry of pancreatic sections indicated the presence of macrophages especially in the peri-insular area of the NOD mice which suggests that IL-1 was produced by macrophages. The levels of IL-1 activity and mRNA in freshly isolated islets from NOD 5-week-old females did not correlate to the iNOS mRNA content or to the nitrite production. However, after incubation with IL-1 in vitro, both NOD and NMRI islets responded with a marked increase in nitric oxide production. It is concluded that the presence of IL-1 in isolated NOD mouse islets, via an induction of iNOS expression and nitric oxide production, cannot explain the gender difference in diabetes incidence in NOD mice.Abbreviations BB BioBreeding - GAPDH glyceraldehyde-3-phosphate dehydrogenase - IDDM insulin-dependent diabetes mellitus - iNOS inducible form of nitric oxide synthase - IL-1 interleukin-1 - IL-1ra interleukin-1 receptor antagonist protein - IL-6 interleukin-6 - NMRI Naval Marine Research Institute - NO nitric oxide - NOD nonobese diabetic - PAP peroxidase-antiperoxidase - PCR polymerase chain reaction - SDS sodium dodecyl sulphate - TNF tumour necrosis factor - OD optical density     

Effects of iron manipulation on trace elements level in a model of colitis in rats

AIM: Trace elements (TE) metabolism is altered in inflammatory bowel diseases. TE (zinc and copper) are constituents of antioxidant enzymes. Iron is involved in the pathogenesis of chronic inflammation. The aim was to evaluate zinc and copper status and the effects of iron manipulation in experimental colitis. METHODS: Twenty-four male Sprague-Dawley rats were divided into four groups: standard diet, iron-deprived diet, iron-supplemented diet, and sham-treated controls. Macroscopic damage was scored. DNA adducts were measured in the colon. Liver and colonic concentration of TE were measured. RESULTS: Macroscopic damage was reduced in iron-deprived groups and increased in iron-supplemented rats. Damage to the DNA was reduced in iron-deprived groups and increased in iron-supplemented groups. Liver and colonic iron concentrations were reduced in iron-deprived and increased in iron-supplemented rats. Liver zinc concentration was reduced after supplementation whereas colonic levels were similar in controls and treated rats. Liver copper concentration was reduced in all the colitic groups except in the iron-supplemented group whereas colonic concentration was increased in iron-deprived rats. CONCLUSION: Iron deprivation diminishes the severity of DNBS colitis while supplementation worsens colitis. Zinc and copper status are modified by iron manipulation.     

Prooxidant properties of 5-aminosalicylic acid

There is a growing body of experimental and clinical evidence to suggest that oral or rectal administration of 5-ASA or 5-ASA conjugates is associated with significant adverse side effects including pancreatitis, hepatitis, and renal toxicity. The objective of this study was to assess the ability of 5-ASA to interact with low-molecular-weight iron to yield oxygen-derived free radicals and to determine whether these oxidants could damage model biological compounds. We found that 5-ASA was very effective at chelating ferric iron (Fe³⁺), and it rapidly reduced Fe³⁺ to the ferrous form (Fe²⁺). Addition of the 5-ASA/Fe²⁺ chelate to solutions containing polyunsaturated fatty acids or deoxyribose resulted in lipid peroxidation and oxidative carbohydrate degradation, respectively. These results are consistent with the formation of the highly reactive (and cytotoxic) hydroxyl radical. Formation of this free radical species was confirmed by the ability of hydroxyl radical scavengers (dimethyl sulfoxide, dimethyl thiourea) to inhibit the 5-ASA/Femediated oxidative reactions. Maximum hydroxyl radical formation was achieved at a 5-ASA-to-Fe³⁺ ratio of 1.0 (20 M 5-ASA and 20 M Fe³⁺). Increasing this ratio significantly inhibited OH·formation with a concomitant reduction in lipid peroxidation and deoxyribose degradation. Finally, we demonstrated that 5-ASA promotes the reductive release of Fe³⁺ from ferritin. Data obtained in this study suggest that 5-ASA may, under certain conditions, promote the formation of potentially injurious free radical species. These oxidative reactions may contribute to some of the adverse side effects known to be associated with the newer preparations of 5-ASA.This work was supported by grants from the NIH (DK39168), the Crohn's and Colitis Foundation of America and Pharmacia-LEO Therapeutics (Uppsala).     

Rebamipide, an Antiulcer Drug, Prevents DSS-Induced Colitis Formation in Rats

This study was conducted to investigate the efficacy of rebamipide against experimental colitis induced by dextran sulfate sodium (DSS) in a rat model of inflammatory bowel disease. Experimental colitis was induced in male Wistar rats by oral administration of 3% DSS solution for one week. The rats were provided with standard diet containing 0.105% rebamipide (160 mg/kg/day) for 1 week. In rats treated with rebamipide, clinical (body weight loss, bloody diarrhea, reduced physical activity, severe anemia, shortened colonic length, and perianal injury) and histopathological (pathological lesion score) findings of DSS colitis were significantly less than in rats with DSS colitis not treated with rebamipide. Rebamipide thus inhibited the induction of colitis. Rebamipide significantly reduced concentrations of both interleukin-1 and GRO/CINC-1 (IL-8-like substance) and cell infiltrates in colonic wall, in parallel with decreased activity of myeloperoxidase. It also reduced expression of IL-1 mRNA but did not influence expression of GRO/CINC-1 mRNA. The attenuation of colonic indices of colitis by rebamipide in this rat model suggests that this drug might have beneficial effects in the treatment of human ulcerative colitis. These effects of rebamipide are attributable to its inhibition of inflammatory cytokine-mediated granulocyte (neutrophil) infiltration into the colon.     

Growth suppression of transformed cells by a human placental extract not related to transforming growth factor Β

Summary We have examined whether human placental extracts contain tumour-growth-inhibitory factors. One fraction (EAP) from such extracts inhibited growth, in soft agar, ofHa-ras-transformed BALB/c 3T3 cells and human squamous lung carcinoma A-2182 cells. However, this fraction had no effect on the anchorage-dependent growth of these cells, although there was a slight mitogenic activity on nontransformed cells. These data together with those on plating efficiency indicated no significant cytotoxicity of EAP on transformed cell lines. Although this fraction contained transforming growth factor (TGF), this cannot account for its inhibitory activity, since (a) pure TGF does not inhibit anchoragedependent growth of Ha-ras-transformed BALB/c 3T3 cells, (b) EAP retains its inhibitory activity in the presence of antibodies against TGF and (c) the inhibitory activity did not copurify with TGF. Partial characterization of our inhibitory factor suggests that the inhibitory factor is a new tumour-growth-inhibitory factor.Abbreviations SDS sodium dodecyl sulphate - TGF or transforming growth factor or - TIF1 or 2 transformed inhibitory factor 1 or 2 - A-2182 human squamous lung carcinoma cell line - BALB/c 3T3 1-1 mouse fibroblast cell line, clone A31 1-1 - BALB/c 3T3 Ha-ras, BALB/c 3T3 1-1 cells transformed by Ha-ras oncogene - CHO Chinese hamster ovary; MEM, minimum essential medium This research was supported by a training grant from Groupement d'Etude et de Recherche sur le Placenta.     

Effect of zinc supplementation on trace elements and intestinal metallothionein concentrations in experimental colitis in the rat

BACKGROUND AND AIM: Zinc enhances cell protection against infection and injury and the healing processes themselves. We evaluated the effect of zinc supplementation at different doses on a model of experimental colitis in the rat. METHODS: Colitis, induced by intra-rectal instillation of dinitrobenzen-sulphonic acid, was assessed at 1 week by examining: general outcome and macroscopic damage, myeloperoxidase activity, mucosal zinc, iron and metallothionein concentrations. Rats received zinc sulphate, 2 mg/kg or 30 mg/kg, twice a day by gavage for 9 days, starting 3 days before the induction of colitis, or intrarectal instillation of zinc (20 mg/kg) once daily starting 8 hours after the induction of colitis and for 6 days thereafter RESULTS: Zinc-treated rats had less diarrhoea, higher body weight and lower colonic weight than untreated rats but no effect was observed on macroscopic inflammation, adhesions, colonic distension and neutrophil infiltration of the colonic mucosa. Zinc supplementation did not affect mucosal iron and zinc concentrations or plasma zinc levels in colitic rats. Metallothionein synthesis was induced in control rats and to a lesser extent in colitic rats. CONCLUSION: Zinc administration induces metallothionein synthesis but has little effect on the short-term course of experimental colitis.     

Effects of acetylsalicylic acid on plasma glucose,free fatty acid,betahydroxybutyrate, glucagon and c-peptide responses to salbutamol in insulin-dependent diabetic subjects

Summary The selective ₂-adrenergic agonist salbutamol increases plasma glucose concentration and the rate of lipolysis when infused in pregnant diabetic women. The aim of the present study was twofold: (a) to focus on the actions of salbutamol on lipid and carbohydrate metabolism in insulin-dependent diabetics; and (b) to investigate possible interferences of acetylsalicylic acid (ASA) with the metabolic responses to i.v. salbutamol. The results obtained during salbutamol infusion (5 g/min) in 6 insulin-dependent diabetic subjects demonstrated that this drug caused sustained increases in plasma glucose, free fatty acid and -hydroxybutyrate concentrations, as well as a small and transient rise of plasma glucagon. No change in plasma C-peptide concentration occurred during salbutamol. A concurrent infusion of lysine acetylsalicylate reduced the increase in free fatty acids by half, blunted the weak glucagon response but enhanced the rise, in plasma glucose following salbutamol administration. The present data show that salbutamol exerts a potent hyperglycemic, lipolytic and ketogenic effect in insulin-dependent diabetics. We suggest that this -adrenergic agent should be used cautiously in human diabetes mellitus.     

Clinical and endoscopic outcomes of patients with colonic Crohn's disease treated with 5-aminosalicylates as monotherapy

BackgroundIn spite of the lack of evidence regarding the clinical benefits of oral 5-aminosalicylic acid (5-ASA) compounds in Crohn's disease (CD), these drugs are frequently used in daily clinical practice, particularly for colonic CD. Our aim is to assess the use and clinical outcomes of 5-ASA of those patients with colonic CD treated with 5-ASA as monotherapy.MethodsPatients diagnosed with isolated colonic CD and treated with 5-ASA but never exposed to immunosuppressants or biologicals were identified from the local databases of five referral centres. A retrospective review of clinical and endoscopic outcomes was performed.ResultsOut of 545 patients with isolated colonic CD, 106 (19%) were treated with oral 5-ASA in monotherapy as maintenance therapy. The median follow-up was 144 months (interquartile range [IQR], 48–234). Almost all of the patients (92%) presented an inflammatory pattern and 11% developed perianal disease. Half of the patients had already received 5-ASA at diagnosis, and the median duration of 5-ASA treatment was 107 months (IQR 22.5–187). Endoscopic remission, as defined by the absence of ulcers at the last complete colonoscopy, was observed in 65% of those patients undergoing at least one colonoscopy during follow-up. Male gender and extraintestinal manifestations were associated with a lower likelihood of achieving endoscopic remission. Nine patients required colectomy, but mostly soon after CD diagnosis.Conclusions5-ASA seems to be of benefit in the long-term in one fifth of patients with colonic CD as the only maintenance therapy and should be considered in fragile patients with Crohn's colitis.     

4-氨基水杨酸对大鼠实验性结肠炎中性粒细胞趋化、活化及凋亡的影响

目的 观察4-氨基水杨酸(4-ASA)对三硝基苯磺酸(TNBS)诱导的大鼠实验性结肠炎炎症损伤、肠组织一氧化氮合酶(iNOS)表达、血中性粒细胞(PMN)凋亡及血清白细胞介素(IL)-8水平等的影响,探讨4-ASA对炎症性肠病(IBD)的治疗作用及机制.方法 40只SD大鼠分为正常对照组(n=10)和实验组(n=30),实验组建立大鼠结肠炎模型.建模第5天将实验组按照处理方式分为实验对照组(n=10,0.9%氯化钠1 ml灌肠),5-ASA组[n=10,5-ASA液(200 mg/kg)1 ml灌肠]和4-ASA组[n=10,4-ASA液(200 mg/kg)1 ml灌肠].连续治疗7 d后处死动物,取病变段肠组织,行结肠大体损伤及结肠组织学损伤评分;生化法检测髓过氧化物酶活性;免疫组化法检测肠组织iNOS表达量;流式细胞术检测血PMN凋亡率;酶联免疫吸附法检测血清IL-8浓度.结果 经4-ASA治疗7d后,4-ASA组大鼠体重明显较实验对照组增加(P<0.01,t=14.09);疾病活动指数评分、大体评分、组织学评分和MPO活性显著较实验对照组降低(t值分别=7.87、18.37、6.66和19.60,P值均<0.01).而5-ASA组与4-ASA组间上述各指标差异均无统计学意义(P值均>0.05).实验对照组肠组织iNOS表达率为(73.55±5.15)%,较正常对照组显著增加[(5.95±1.45)%,t=39.93,P<0.01)];5-ASA和4-AsA组大鼠肠组织iNOS表达率分别为(37.80±3.82)%和(42.27±3.52)%,均较实验对照组显著降低(t值分别=17.62和15.76,P值均<0.01).实验对照组血清IL-8的平均浓度明显高于正常对照组(t=25.25,P<0.01);5-ASA和4-ASA组明显低于实验对照组(t值分别=12.31和11.57,P值均<0.01).实验对照组血PMN凋亡率明显低于正常对照组(t=11.48,P<0.01);5-ASA和4-ASA组凋亡率明显高于实验对照组(t值分别=7.51和10.47,P值均<0.01).结论 4-ASA灌肠对实验性结肠炎大鼠具有显著的治疗作用,其治疗机制可能与降低PMN的趋化与激活、上调血PMN凋亡率、减少肠组织局部损伤因子有关.     

Innate immunity and colonic inflammation: enhanced expression of epithelial alpha-defensins

Human -defensins contribute to local intestinal host defense as part of innate immunity and may be of major relevance in microbial infection and chronic inflammatory bowel disease. The objective was to investigate human defensin 5 and 6 (HD-5, HD-6) mRNA expression by RT-PCR from colonic biopsies and peptide expression by immunohistochemistry from colonic resections under basal and inflammatory conditions. Both -defensins were induced by proinflammatory cytokines in cell culture. HD-5 mRNA expression was enhanced in both idiopathic and nonidiopathic inflammatory states of the large bowel [32% of control vs 73% of unspecific colitis, 69% of Crohns disease (CD) and 73% of ulcerative colitis (UC)], whereas HD-6 was specifically related to CD and UC (14% in controls vs 20% in unspecific coltis, 49% in CD and 42% in UC). Immunohistochemistry confirmed the presence of HD-5 in colonic epithelium. Antimicrobial peptides in the colon may be of importance in maintaining the mucosal barrier and controlling microbial invasion in inflammatory bowel diseases.     

Plasma acidic glycohydrolases in insulin-dependent diabetes mellitus

Summary We assayed plasma activities of -galactosidase, -hexosaminidase, -mannosidase, -fucosidase and -galactosidase involved in degradation of the glycoprotein molecule in 110 insulin-dependent diabetics aged 3-1/2 to 19 years and compared them to a group of normal youngsters. We correlated the plasma enzyme activities with the duration, control and sequelae of insulin-dependent diabetes. Insulin-dependent diabetics had a significantly higher plasma activity of -hexosaminidase and -mannosidase (p<0.01) and a significantly lower plasma activity of -fucosidase and -galactosidase (p<0.01). Of the 5 enzymes studied, only plasma -hexosaminidase correlated with fasting and postprandial blood sugar (p<0.01), cholesterol and triglycerides (p<0.05). Additionally, poor control of diabetes was also associated with a significantly higher plasma -hexosaminidase activity (p<0.01). Proteinuria or an abnormal Addis count suggestive of renal involvement was associated with various changes in plasma acidic hydrolases. These changes may be related to insulin deficiency rather than hyperglycemia and may be genetically determined.Deceased on August 2, 1981.     

The intestinal anti-inflammatory activity of UR-12746S on reactivated experimental colitis is mediated through downregulation of cytokine production

BACKGROUND: UR-12746S (dersalazine sodium) is cleaved by colonic bacteria delivering the PAF antagonist UR-12715 and 5-ASA. This study describes the anti-inflammatory activity of UR-12746S in an experimental model of reactivated colitis and its effects on cytokine production. METHODS: Rats were initially rendered colitic by a colonic instillation of 10 mg of trinitrobenzenesulphonic acid (TNBS) dissolved in 0.25 ml of 50 % ethanol, and colitis was reactivated two weeks after by a second administration of the same dose of TNBS. Two groups of colitic rats received UR-12746S (25 and 50 mg/kg daily, p.o.) and colonic damage was evaluated every week for 4 weeks. Different biochemical markers of colonic inflammation were assayed: MPO activity and cytokine (IL-1beta and TNFalpha) levels. Also, the in vitro effects of UR-12715 and 5-ASA on cytokine production were assayed. RESULTS: UR-12746S showed anti-inflammatory effect in reactivated colitis in rats, as evidenced by a significant reduction in MPO activity. Both doses of UR-12746S decreased IL-1beta production, while only the highest dose assayed inhibited TNFalpha production. In vitro studies revealed that UR-12715 or 5-ASA (from 10(-6) to 10(-4) M) inhibited IL-8 production (30-40%) in HT-29 cells when incubated with LPS. This inhibitory effect was enhanced when both compounds were administered simultaneously at 10(-4) M. In addition, UR-12715 inhibited IL-1beta or TNFalpha production in THP-1 or U937 cells, respectively, when these cells were stimulated by PMA and LPS; whereas 5-ASA only showed a weak effect in inhibiting IL-1beta production. CONCLUSION: UR-12746S was able to prevent relapse in experimental colitis and inhibition of proinflammatory cytokine production participates in the intestinal anti-inflammatory activity exerted by this compound.