Injury In Rat Small Intestine Research Articles

Resveratrol Modulates γ-rays-induced Acute Small Intestinal Injury in Rats

Resveratrol Modulates γ-rays-induced Acute Small Intestinal Injury in Rats

Pretreatment with a Phosphodiesterase-3 Inhibitor, Milrinone, Reduces Hepatic Ischemia-Reperfusion Injury, Minimizing Pericentral Zone-Based Liver and Small Intestinal Injury in Rats.

BackgroundSevere pericentral zone (zone 3)-based liver injury (LI) may become intractable, with allograft dysfunction after liver transplantation. The phosphodiesterase-3 inhibitor, milrinone, has been reported to attenuate hepatic ischemia–reperfusion injury (IRI). This study clarified how hepatic IRI involved zone 3-based LI, in which zone milrinone was effective, and whether milrinone could improve small intestinal injury (SII) with hepatic IRI.Material/MethodsRats were divided into sham, ischemia–reperfusion (IR), or IR+milrinone groups (n=13 per group). Milrinone was administered intraportally via intrasplenic injection, and whole hepatic ischemia was induced for 30 min. Five hours after reperfusion, serum chemistry and histopathological findings were compared. Expression of CD34 for the detection of altered sinusoidal endothelium as sinusoidal capillarization and cleaved caspase-3 as an apoptosis marker were analyzed via immunohistochemistry. Survival rates were examined after 45 min of whole hepatic ischemia.ResultsSerum aspartate aminotransferase and direct bilirubin levels were significantly decreased in the IR+milrinone group compared with those of the IR group. The degree of LI, sinusoidal capillarization and apoptosis at zone 3 in the IR group was significantly increased compared with those at the periportal zone (zone 1). These findings at zone 3 in the IR group were improved in the IR+milrinone group. SII with villus congestion and apoptosis in the IR group was significantly attenuated in the IR+milrinone group. The 7-day survival rate was significantly elevated in the IR+milrinone group as compared with that of the IR group.ConclusionsA hepatic IRI model caused zone 3-based LI and SII, which were attenuated by intraportal administration of milrinone.

Sa1568 – Pretreatment with the Phosphodiesterase-3 Inhibitor Milrenone Reduces Hepatic Ischemia–Reperfusion Injury, Minimizing Zone 3-Based Liver Parehchymal and Small Intestinal Injury in Rats

Sa1568 – Pretreatment with the Phosphodiesterase-3 Inhibitor Milrenone Reduces Hepatic Ischemia–Reperfusion Injury, Minimizing Zone 3-Based Liver Parehchymal and Small Intestinal Injury in Rats

Plasma citrulline is a sensitive safety biomarker for small intestinal injury in rats

Plasma citrulline is decreased in cases of severe intestinal injury with apparent villus and cellular atrophy. However, the fluctuation of plasma citrulline in slight intestinal injury remains to be investigated. To clarify this, irinotecan at 30 mg/kg or 60 mg/kg was administered intravenously to rats. Irinotecan reduced plasma citrulline concentrations compared to those in the pair-fed control, being concurrent with slight single cell necrosis and mucosal epithelium regeneration in the small intestine without apparent villus and cellular atrophy. Gene expression of enzymes converting glutamine to citrulline was decreased in the small intestine of the injury model. Moreover, citrulline and arginine levels in the ileum were decreased without alterations to glutamine and glutamate levels, indicating that citrulline synthesis from glutamine was impaired. Metabolome analysis revealed that plasma citrulline and arginine levels were decreased, while there were no marked alterations in other amino acids, metabolites of glycolysis, ketone bodies, or fatty acids. These results suggested that a decreased plasma citrulline level was unlikely to result from amino acid catabolism in response to malnutrition. In conclusion, plasma citrulline concentration reflects slight intestinal injury without apparent villus and cellular atrophy, and thus, it would be a sensitive biomarker for the small intestinal injury.

Role of MAPKs in HSP70's Protection against Heat Stress-Induced Injury in Rat Small Intestine.

Aim To evaluate the role of heat shock protein 70 (HSP70) on the MAPK pathway activation with quercetin treatment and its protection against small intestine impairments of heat stressed rats. Methods Forty-eight male Sprague-Dawley rats aged 6 weeks were randomized to three groups (n=16/group), namely, control (CON), heat stress (HS), and heat stress + quercetin (HQ). The experiment lasted for 14 days with daily 50 min of heat stress treatment (43°C) for the HS and HQ groups. Rats of HQ group were intragastrically given 0.5 ml quercetin solution (50 mg/kg body weight) before the heat stress treatment. Half of the animals were sacrificed on day 7 and the rest on day 14 for tissue sampling. Intestinal morphology, small intestine morphology and permeability, protein expression of HSP70, phosphorylation of extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), p38 mitogen-activated protein kinase (MAPK), and caspase-3 activity were examined. Results Heat stress caused morphological damage to the small intestine and increased intestinal permeability. HSP70 expression and MAPK activity in the small intestine were increased by heat stress. Inhibition of HSP70 by quercetin did not change intestinal permeability compared with the HS group but aggravated intestinal injury and affected the activation of MAPKs and caspase-3. Conclusions HSP70 may modulate stress-activated signaling and acts in a protective manner via MAPK signaling. Affecting HSP70 protective mechanisms could be useful for protection against heat stress-induced injury in rat small intestine.

NF-κB-iNOS-COX2-TNF α inflammatory signaling pathway plays an important role in methotrexate induced small intestinal injury in rats

Although methotrexate is widely used in clinics as an anticancer agent, it's utility is limited by its gastrointestinal toxicity, the mechanism of which is unclear. The role of NFκB inflammatory pathway in MTX induced mucositis was investigated in the present study. GI injury was induced in adult Wistar rats by the administration of 3 consecutive i.p . injections of MTX. On the fourth day, the rats were sacrificed and the small intestine was removed; A piece was used for light microscopy, immunohistochemistry, immunofluorescence studies . The mucosa was collected and used for the analysis of protein and mRNA expressions of NFκB and its target genes by the western blot, RT-PCR respectively. MTX treatment resulted in NFκB activation and nuclear translocation as evidenced by immunofluorescence, immunohistochemistry , and western blot. NFκB mRNA was also increased. There was increased protein and mRNA expressions of NFκB target genes, TNF-α, iNOS, COX-2, PLA2, HO-1, HSP70, MMPs 2 and 9 . Aminoguanidine pretreatment (30mg/ 50mg /kg body wt.) attenuated MTX induced activation of NFκB and its proinflammatory target genes and improved MTX induced morphological changes. Aminoguanidine has protective effects against MTX induced gastrointestinal mucositis in rats.

Activation of the mitochondrial apoptotic pathway contributes to methotrexate-induced small intestinal injury in rats.

The efficacy of methotrexate (MTX), a commonly used chemotherapeutic drug, is limited by intestinal injury. As the mechanism of MTX-induced small intestinal injury is not clear, there is no definitive treatment for MTX-induced gastrointestinal injury. The present study investigates the role of mitochondrial apoptotic pathway in MTX-induced small intestinal injury and examines whether aminoguanidine is effective in preventing the damage. Eight Wistar rats were administered 3 consecutive i.p. injections of 7mg/kg body wt. MTX. Some rats were pretreated with 30mg or 50mg/kg body wt. of aminoguanidine (n=6 in each group). Protein expressions of cytochrome c, caspases 3 and 9, and PARP-1 were determined in the small intestines by immunohistochemistry and western blot. Mitochondrial pathway of apoptosis was activated in the small intestines of MTX-treated rats as evidenced by intense immunostaining for cyt c, caspases 9 and 3, and PARP-1 and mitochondrial release of cyt c, activation of caspases, and PARP-1 cleavage by Western blot. Immunofluorescence revealed increased nuclear localization of PARP-1. Aminoguanidine pretreatment ameliorated MTX-induced small intestinal injury in dose-dependent manner and inactivated the mitochondrial apoptotic pathway. Aminoguanidine may possess beneficial intestinal protective effects as an adjuvant co-drug against MTX intestinal toxicity during cancer chemotherapy. As the mechanism of MTX-induced small intestinal injury is not clear, there is no definitive treatment for MTX-induced gastrointestinal injury. The results of the present study show that the mitochondrial pathway of apoptosis plays a role in MTX-induced small intestinal injury as evidenced by cytochrome c release, activation of caspases 9 and 3, PARP-1 cleavage, and DNA fragmentation. Aminoguanidine (AG) pretreatment attenuates the severity of small-intestinal injury induced in rats by MTX treatment. The mechanisms of action of AG involve inhibition of iNOS, and mitochondrial pathway of apoptosis. It is suggested that aminoguanidine may possess beneficial intestinal protective effects as an adjuvant co-drug against MTX intestinal toxicity during cancer chemotherapy.

Effect of mesenchymal stem cells on small intestinal injury in a rat model of acute necrotizing pancreatitis

BackgroundAcute necrotizing pancreatitis (ANP) is often complicated by multiple organ failure. The small intestine is frequently damaged during ANP. Capillary leakage in multiple organs during ANP is one of the most important causes of multiple organ dysfunction. Damage to the capillary endothelial barrier and impaired water transportation could lead to capillary leakage in ANP.MethodsSprague–Dawley (SD) rats were randomized into a control group, the ANP group, the culture media-treated group, or the bone marrow-derived mesenchymal stem cell (BMSC)-treated group (30 rats in each group). Ten rats in each group were sacrificed at 6, 12, and 24 h after induction of experimental models. Serum, ascites, pancreatic, and small intestinal samples were collected. The levels of serum and ascites albumin and amylases were measured, pancreatic histology was assessed, and the connection changes between vessel endothelial cells were evaluated using scanning electron microscopy (SEM). Capillary leakage in small intestinal tissue was observed visually by tracking fluorescein isothiocyanate (FITC)-albumin, and was measured by the Evans blue extravasation method. The location and expression of aquaporin 1 (AQP1) in the small intestine was analyzed using immunohistochemistry, real-time polymerase chain reaction (PCR), and Western blot.ResultsThe outcomes showed that the level of serum and ascites amylase is elevated. Conversely, the level of serum albumin is decreased while ascites albumin is elevated. There is damage to pancreatic tissue, and the small intestinal capillary endothelial barrier was aggravated. Furthermore, the expression of AQP1 was reduced significantly after induced ANP. Following treatment with MSCs, the elevation of amylase and the decrease of serum albumin were inhibited, the damage to pancreatic tissue and the level of small intestinal capillary leakage was alleviated, and the downregulation of AQP1 was reversed.ConclusionsIn conclusion, MSC therapy could alleviate small intestinal injury in rats with ANP, the mechanism of which might be related to reduction of damage to the small intestinal capillary endothelial barrier, and increased expression of AQP1 in the small intestine.

117 - Role of Oxidative Stress in Acetyl Salicylic Acid (ASA)-Induced Small Intestinal Injury in Rats

Background and Aim Although ASA-induced small intestinal mucosal injury has been reported to be quite common, the pathogenesis is not yet. We have reported ASA increases small intestinal epithelial cell permeability as a first step of small intestinal mucosal injury via ROS and ROS-modified ZO-1 protein using an in vitro model. In this study, we clarified the pathogenesis using an ex vivo and an in vivo model. Methods In an in vivo study, ASA (200mg/kg) was injected into the proximal duodenum of rats (male Sprague-Dawley, 9 weeks old). After treatment, the small intestine was removed for histological examination and 1% Evans blue was injected (i.v.) to visualize intestinal lesions. In an ex vivo study, we measured ASA (50-200mM)-induced small intestinal mucosal permeability using the Ussing chamber by assessing the flux of FITC-dextran. ASA-induced oxidative stress in small intestine was assessed by the expression of HNE-modified protein using western blotting. Results In an in vivo study, ASA induced mucosal injury, especially in the jejunum, that was confirmed by the histological and Evans blue methods. In an ex vivo study, ASA increased the flux of FITC-dextran in a concentration dependent manner. At the same time, ASA increased HNE-modified proteins in small intestine. Conclusion ASA-induce small intestinal injury can be caused by increased oxdative stress in the mucosa.

C5a inhibitor protects against ischemia/reperfusion injury in rat small intestine.

ABSTRACTAcute mesenteric ischemia (AMI) is caused by considerable intestinal injury, which is associated with intestinal ischemia followed by reperfusion. To elucidate the mechanisms of ischemia/reperfusion injuries, a C5a inhibitory peptide termed AcPepA was used to examine the role of C5a anaphylatoxin, induction of inflammatory cells, and cell proliferation of the intestinal epithelial cells in an experimental AMI model. In this rat model, the superior mesenteric artery was occluded and subsequently reperfused (Induce‐I/R). Other groups were treated with AcPepA before ischemia or reperfusion. Induce‐I/R induced injuries in the intestine and AcPepA significantly decreased the proportion of severely injured villi. Induce‐I/R induced secondary receptor for C5a‐positive polymorphonuclear leukocytes in the vessels and CD204‐positive macrophages near the injured site; this was correlated with hypoxia‐induced factor 1‐alpha‐positive cells. Induction of these inflammatory cells was attenuated by AcPepA. In addition, AcPepA increased proliferation of epithelial cells in the villi, possibly preventing further damage. Therefore, Induce‐I/R activates C5a followed by the accumulation of polymorphonuclear leukocyte and hypoxia‐induced factor 1‐alpha‐producing macrophages, leading to villus injury. AcPepA, a C5a inhibitory peptide, blocks the deleterious effects of C5a, indicating it has a therapeutic effect on the inflammatory consequences of experimental AMI.

Muscovite Ameliorates Diclofenac-Induced Small Intestinal Injury in Rats via the Inhibition of Protease-Activated Receptor 2 Activity

Introduction: The pathogenesis of non-steroidal anti-inflammatory drugs(NSAIDs)- induced small intestinal lesions was still unclear, although it is consistent with recent capsule endoscopy evidence suggesting that NSAID-induced injury to the lower gut is much more prevalent than was once thought. Nonetheless, there is still no established strategy for the treatment and prevention of smallintestinal damage induced by NSAIDs. The aim of this study was to observe the effect of traditional Chinese medicine muscovite to diclofenac-induced small intestinal injury in rats. And to research the possible target spot in the prophylaxis and treatment of diclofenac-induced small intestinal injury by muscovite, in order to provide the further experimental basis for the treatment of NSAIDs enteropathy by TCM. Methods: Observed the small intestinal morphology by general damage score and Chiu score under light microscope of mucous membrane of small intestine. Observed cell ultrastructure by transmission electron microscope and scanning electron microscopy, tested portal endotoxin by dynamic turbidimetry, tested tryptase, PAR-2, ERK1/2, Occludin by immunohistochemistry, and analysed PAR-2 mRNA by real-time fluorescence quantification. Results: There were edema, scattered erosion and several superficial ulcer of mucous membrane of small intestine in muscovite group. The general score and tissue score in muscovite were lower than model group (P1.633 ±0.122) was lower than model group (P < 0.05), and the difference had statistical significance. Conclusion: We found that the total optical density of tryptase, PAR-2 protein and ERK1/2 in muscovite group were obviously lower than which in model group, occludin of mucous membrane of small intestine in muscovite was obviously higher than model group. The level of PAR-2 mRNA in muscovite groupwas lower than model group and the difference had statistical significance. This suggests that the prophylaxis and treatment of NSAID-induced intestinal damage by muscovite is related with active suppression of tryptase, reduction of PAR-2 excitation, and reduction of expression of ERK1/2 passageway with reducing the lesion of occludin.Figure 1Figure 2Figure 3

Activation of transcription factor AP-1 in response to thermal injury in rat small intestine and IEC-6 cells.

BackgroundOur previous studies indicated that heat stress can cause significant damage to the intestinal epithelium and induce differential expression of many genes in rat small intestine. The transcription factors AP-1 and NF-κB, which act as important mediators by binding to specific DNA sequences within gene promoters, regulate the transcription of genes associated with immune regulation, stress response and cell fate.MethodsTo determine whether AP-1 and NF-κB are involved in hyperthermia-induced injury in rat small intestine and IEC-6 cells, we investigated their activity, and the expression of related proteins, by electrophoretic mobility shift assays and western blotting, respectively.ResultsHeat stress resulted in severe damage to the epithelium of the small intestine. The cell morphology and viability were obviously altered when IEC-6 cell was exposed to hyperthermia. AP-1 was activated in the small intestine of heat-stressed rats, as was phosphorylation of the JNK signaling pathway. In IEC-6 cell line, AP-1 activation in groups exposed to 42 °C for 1 h, 2 h and 4 h was significantly increased. In contrast, NF-κB was not activated in both in vivo and in vitro models.ConclusionThese results reveal that AP-1 is likely to play an important role in regulating gene transcription in rat small intestine and IEC-6 cells during exposure to heat stress.Electronic supplementary materialThe online version of this article (doi:10.1186/s12876-015-0309-z) contains supplementary material, which is available to authorized users.

Quantitative proteomic analysis reveals heat stress-induced injury in rat small intestine via activation of the MAPK and NF-κB signaling pathways.

The intestinal epithelium plays a critical role in absorbing nutrients and maintaining the integrity of the gut barrier. Extreme heat stress induces damage to the intestinal epithelium. However, the protein expression changes and the mechanism behind this damage remain poorly understood. In this study, morphological observation showed that heat stress induced desquamation of intestinal epithelial cells, and destruction of intestinal microvilli and mitochondria. Heat stress-induced changes in the intestinal proteome were quantified using the iTRAQ method followed by mass spectrometry and software analysis. A total of 1689 proteins were identified in rat intestine tissue, of which 41 showed significantly altered expression between the heat stressed and control groups. However, these proteins with significant alterations were involved in biological processes such as cellular assembly and organization, developmental disorder, organismal injury and abnormalities, and inflammation. We found that members of the MAPK and NF-κB signaling pathways act as hub proteins in the network interaction analysis. Furthermore, western blot analysis verified that the MAPK and NF-κB signaling pathways were activated by heat stress as expected. This study suggests that heat stress induces cell cytoskeleton reorganization and an inflammatory response, and the activation of the MAPK and NF-κB signaling pathways, which may ultimately contribute to intestinal injury.

Mechanism of nonsteroidal antiinflammatory drugs-induced injury in rats small intestinal epithelial barrier and the effects of drug interfering

Objective To investigate the assessment methods and mechanisms of nonsteroidal antiinflammatory drugs （NSAID）-induced injury in rat small intestinal epithelial barrier,and to explore the protective effects of mucosal protective agents and antacids on it.Methods A total of 96 rats were evenly divided into the morphologic observation group and the mechanism research group,and 48 in each group.Then each group was evenly divided into eight subgroups：the healthy control group,the model group （model established with indomethacin）,the teprenone prevention group,the rabeprazole prevention group,the treatment control group,the teprenone treatment group,the rabeprazole treatment group and the teprenone and rabeprazole combined group （combined group）,six in each group.Exfoliated cells gap density of small intestine of each subgroup was determined by confocal laser endomicroscopy.Serum level of tumor necrosis factor-α （TNF-α）was measured with enzyme-linked immunosorbent assay （ELISA）. The expression of nuclear factor-κB （NF-κB）,caspase-3,zonula occludens-1 （ZO-1 ）and occludin at protein level was detected by Western blotting.The LSD-t test or Hamhane′s T2 test was performed for statistical analysis.Results The exfoliated cells gap densities of the teprenone prevention group and the rabeprazole prevention group were （57.43 ± 24.55 ）/1 000 and （59.80 ± 21 .14 ）/1 000,respectively, which were both lower than that of the model group （（110.93±50.58）/1 000）,and the differences were statistically significant （t= 53.50 and 54.13,both P 〈 0.01 ）.The exfoliated cells gap density of the combined group was （40.53 ±15 .39）/1 000,which was lower than that of the treatment control group （（93.80±40.65 ）/1 000 ）,and the difference was statistically significant （t =44.27,P 〈0.01 ）.The serum levels of TNF-α of the teprenone prevention group and the rabeprazole prevention group were （25 .80±8.97）ng/L and （22.74 ±7.15 ）ng/L,repsectively,which were both lower than that of the model group （（44.48 ± 7.42 ）ng/L）,and the differences were statistically significant （t = 18.68 and 21 .74,both P 〈0.01 ）.The serum level of TNF-αof the combined group （（13.66 ±4.98）ng/L）was lower than that of the treatment control group （（24.67±6.70）ng/L）,and the difference was statistically significant （t = 9.02,P 〈 0.01 ）.The caspase-3 levels of teprenone prevention group and rabeprazole prevention group were 1 .47 ±0.35 and 1 .58 ±0.34,and the NF-κB levels of these two groups were 1 .27±0.14 and 1 .21 ± 0.10,respectively.Compared with those of model group （2.44 ± 0.45 and 1 .69±0.13）,the differences were statistically significant （t =0.97,0.86,0.42 and 0.48,respectively, all P 〈0.01 ）.The levels of caspase-3 and NF-κB of the combined group were 0.66±0.06 and 0.44 ± 0.21 ,respectively,which were lower than those of the treatment control group,and the differences were statistically significant （t=0.34 and 0.56,both P 〈0.01）.The expressions of occludin at protein level of the teprenone prevention group and the rabeprazole prevention group were 0.69 ±0.16 and 0.74 ±0.11 , and the levels of ZO-1 were 0.81 ± 0.08 and 0.84 ± 0.12.Compared with those of the model group （0.45 ±0.22 and 0.64±0.07 ）,the differences were statistically significant （t =0.24,0.29,0.17 and 0.21 ,respectively,all P 〈0.01 ）.The levels of occludin and ZO-1 of the combined group were 2.50 ± 0.46 and 1 .76±0.18,which were higher than those of the treatment control group,and the differences were statistically significant （t =1 .50 and 0.76,both P 〈0.01 ）.Conclusions The exfoliated cells gap density may be a valuable indicator to predict the degree of inflammation response and permeability of epithelial barrier as well as to evaluate efficacy of medication.Teprenone and rabeprazole have prevention and treatment effects on NSAID-induced injury in rat small intestine. Key words: Microscopy, confocal; Epithelial barrier; Exfoliated cells gap density; Tumor necrosisfactor-alpha; NF-kappa B; Tight junctions protein

Tu1239 Prophylactic Effects of Proton Pump Inhibitors on NSAIDs Induced Small Intestinal Injury in Rats

Background and Aim: Non-steroidal anti-inflammatory drugs (NSAIDs) is known to cause mucosal injury in not only the upper gastrointestine but also the small intestine. Proton pump inhibitors(PPIs) are useful for the treatment of upper gastrointestinal mucosal injuries induced by NSAIDs. However, it was reported that some kinds of PPI exacerbate NSAIDsinduced small intestinal injury. The mechanism of NSAIDs-induced small intestinal injury is unclear and acid is not related to its mucosal injury. In this study, we confirmed effects of each PPIs which suppress gastric acid secretion for indomethacin(IM)-induced small intestinal mucosal injury and investigated the molecular mechanism of PPI which protected small intestinal injury induced by indomethacin. Methods: (In vivo study) Male SD rats were orally administered IM (10 mg/kg) and their small intestines were resected 24 hours later. We measured the ulcer index, MPO activity, iNOS-mRNA expression, and bacterial count. PPIs were orally administered 30 min before IM administration:lansoprazole (30 mg/ kg or 100 mg/kg) or omeprazole (30 mg/kg or 100 mg/kg). In addition, we investigated the effects of lansoprazole or omeprazole on heme oxygenase-1(HO-1), which is deeply involved in mucosal protection. (in vitro study) We confirmed the expression of HO-1 by realtime PCR andWestern Blotting in IEC-6 stimulated lansoprazole, IM, or lansoprazole+IM. We also confirmed how these drugs affect cell mass culturing by MTT assay and examined participation of NF-E2 related factor 2(Nrf2). Results: (1)Among PPIs, only lansoprazole inhibited small intestinal lesions. (2)Lansoprazole inhibited iNOS-mRNA expression, MPO activity, and the bacterial count in the infiltrated intestinal mucosa. (3) The amount of HO1 protein in the intestinal mucosa was significantly increased by lansoprazole but not by omeprazole. Prior administration of carbonmonoxide (CO)-releasingmolecule-2 significantly reduced the severity of these lesions, suggesting that lansoprazole ameliorates small intestinal ulceration through upregulation of HO-1/CO. (4) IM induced the expression of HO-1 at maximum 6hours, lansoprazole at 12hours, and lansoprazole+IM at 12hours after administration of drugs in IEC-6. Lansoprazole induced the expression Nrf2 at 6hours later. Knock down of Nrf2 decreased the preventive effect of lansoprazole in IEC-6. Conclusion: Among PPIs, only lansoprazole suppressed IM-induced small intestinal injury. Lansoprazole induced the expression of HO-1 and the protective effect of lansoprazole against IM-induced small intestinal injury was related to HO-1 inducted by Nrf2.

Pattern recognition analysis of proton nuclear magnetic resonance spectra of extracts of intestinal epithelial cells under oxidative stress.

Mesenteric ischemia-reperfusion induces gut mucosal damage. Intestinal mucosal wounds are repaired by epithelial restitution. Although many different molecular mechanisms have been shown to affect cell metabolism under oxidative conditions, these molecular mechanisms and metabolic phenotypes are not well understood. Nuclear magnetic resonance (NMR) spectroscopic data can be used to study metabolic phenotypes in biological systems. Pattern recognition with multivariate analysis is one chemometric technique. The purpose of this study was to visualize, using a chemometric technique to interpret NMR data, different degrees of oxidant injury in rat small intestine (IEC-6) cells exposed to H2O2. Oxidant stress was induced by H2O2 in IEC-6 cells. Cell restitution and viability were assessed at different H2O2 concentrations and time points. Cells were harvested for pattern recognition analysis of (1)H-NMR data. Cell viability and restitution were significantly suppressed by H2O2 in a dose-dependent manner compared with control. Each class was clearly separated into clusters by partial least squares discriminant analysis, and class variance was greater than 90% from 2 factors. Pattern recognition of NMR spectral data using a chemometric technique clearly visualized the differences of oxidant injury in IEC-6 cells under oxidant stress.

Intravesical Application of Rebamipide Suppresses Bladder Inflammation in a Rat Cystitis Model

We examined the effects of intravesical application of rebamipide (Otsuka Pharmaceutical, Tokyo, Japan) on bladder inflammation and overactivity in a chemically induced cystitis model. Female Sprague Dawley® rats under isoflurane anesthesia were injected with 150 mg/kg cyclophosphamide in the peritoneum, and 1 mM or 10 mM rebamipide or vehicle was administered in the bladder and remained for 1 hour. Control rats were injected with saline in the peritoneum and vehicle was administered in the bladder. The bladder was harvested at 48 hours. Hematoxylin and eosin staining was performed and the inflammation grade was assessed. The amount of myeloperoxidase was measured using enzyme-linked immunosorbent assay. Proinflammatory cytokines were quantified using reverse transcriptase-polymerase chain reaction. Cystometrogram was done in awake rats 48 hours after cyclophosphamide treatment to measure voiding reflex parameters. Histological evaluation revealed that bladder inflammation in cyclophosphamide treated rats was suppressed by rebamipide in a dose dependent manner. Up-regulated myeloperoxidase, IL-1β, IL-6 and TNF-α expression in cyclophosphamide treated rats was also suppressed in rebamipide treated rats. Cystometrogram demonstrated that the intercontraction interval decreased in cyclophosphamide treated rats but was prolonged by rebamipide. Intravesical application of rebamipide suppressed bladder inflammation and overactivity in a dose dependent manner. This may provide a new treatment strategy for chemotherapy associated cystitis.

Latest concepts on the association between nonsteroidal anti-inflammatory drug-induced small intestinal injury and intestinal bacterial flora.

Luminal bacteria, one of the main aggressive factors of nonsteroidal anti-inflammatory drugs (NSAIDs), induce small intestinal mucosal injury. Because most bacteria invading from the mouth are eliminated by the highly acidic gastric environment, the upper small intestine contains relatively low numbers of microorganisms. With decreased peristalsis, decreased acidity, and lower oxidation-reduction potential, the ileum maintains a more diverse microflora and a higher bacterial population. As NSAID-induced small intestinal ulcerations tend to localize in the small intestinal distal part, as viewed by capsule endoscopy, the ulcers are in contact with a large amount of luminal bacteria. Recently, it was reported that proton-pump inhibitors (PPIs) exacerbate NSAID-induced small intestinal injury in rats. The study showed that PPIs impair the ability to disinfect due to the PPI-induced low acidic gastric environment, and this resulted in transubstantiation of intestinal flora which exacerbated NSAID-induced small intestinal injury. If it is true that PPIs exacerbate small intestinal injury, the methods of preventing NSAID-induced gastroduodenal injury to defend PPI-induced small intestinal injury should be reconsidered. Following several studies, there may be a possibility that probiotics and prebiotics are useful treatments for the prevention of NSAID-induced small intestinal injury. A method of determining bacterial flora maintenance including alteration of the environment and the administration of various drugs is required.

Epidermal Growth Factor Promotes Proliferation and Improves Restoration After Intestinal Ischemia–Reperfusion Injury in Rats

Epidermal growth factor (EGF) is an attractive and promising therapeutic application for intestinal disorders. The current study examined its influence on proliferation and restoration after ischemia-reperfusion (I/R) injury in rat small intestine. Six groups were performed: sham operation (Con); ischemia for 30min with subsequent reperfusion for 30min (I/R); I/R injured with 500μg/kg EGF injected 5min before ischemia (Pre-l); I/R injured with 50μg/kg EGF injected 5min before ischemia (Pre-s); I/R injured with 500μg/kg EGF injected 5min after reperfusion (Post-l); and I/R injured with 50μg/kg EGF injected 5min after reperfusion (Post-s). Intestinal histological damage, crypt cell proliferation degree, mucosal permeability, tight junction proteins expression, and levels of inflammation factors were studied for each group. Compared with the I/R group, administration of EGF in the Pre-l, Pre-s, and Post-l groups all presented a significant proliferation effect. The levels of FD4, IL-6, and TNF-α were dramatically decreased in all EGF-treated groups. Histological destruction was improved and TJs recovery was notably accelerated in all EGF-treated groups except the Post-s group. D-lactate concentration was only diminished in the Pre-l group. These results suggest that mucosally applied EGF can promote intestinal proliferation and improve restoration after I/R injury. EGF intraluminal administration is an effective treatment against intestinal I/R injury.

Rebamipide ameliorates indomethacin‐induced small intestinal injury in rats via the inhibition of matrix metalloproteinases activity

The pathogenesis of non-steroidal anti-inflammatory drugs (NSAIDs)-induced small intestinal lesions remains unclear, although it is considered to be quite different from that of upper gastrointestinal tract ulcers due to the absence of acid and the presence of bacteria and bile in the small intestine. The aim of this study was to characterize specific gene expression profiles of intestinal mucosa in indomethacin-induced small intestinal injury, and to investigate the effects of rebamipide on the expression of these genes. Intestinal injury was induced in male Wistar rats by subcutaneous administration of indomethacin. Total RNA of the intestinal mucosa was extracted 24 h after indomethacin administration, gene expression was investigated using microarray analysis, and the identified genes were confirmed by real-time polymerase chain reaction (PCR). In addition, we investigated whether the treatment with rebamipide altered the expression of these identified genes. The administration of indomethacin induced small intestine injuries, and these lesions were significantly inhibited by the treatment with rebamipide. Microarray analysis showed that the genes for several matrix metalloproteinases (MMPs) and several chemokine-related genes were significantly upregulated, and metallothionein 1a (MT1a) was downregulated in the intestinal mucosa after administration of indomethacin. The expressions of these genes were reversed by the treatment with rebamipide. These data suggest that MMPs, chemokines, and MT1a may play an important role in the intestinal mucosal injury induced by indomethacin. In particular, the inhibition of MMP genes and chemokine-related genes by rebamipide may be important for the therapeutic effect against NSAIDs-induced small intestinal injury.