Glutamine supplemented parenteral nutrition prevents intestinal ischemia- reperfusion injury in rats

AIM: To examine whether glutamine prevents the injury to the intestinal mucosa after intestinal ischemia-reperfusion (I/R) in rats. METHODS: Thirty male Sprague-Dawley rats were randomly divided into 3 groups: a standard parenteral nutrition (PN) group (n = 10); an I/R-PN group (n = 10); an I/R-glutamine enriched PN (I/R-Gln) group (n = 10). The superior mesenteric artery (SMA) was clamped. After 60 min of ischemia, reperfusion was initiated and infusion was started. All rats received isocaloric and isonitrogenous nutritional support for 48 h. Spleen, liver, mesenteric lymph nodes (MLN), and intestinal segments were removed for morphological and biochemical analyses, and blood samples were collected for bacterial culture and measurement of endotoxin levels. The permeability of intestinal mucosa was assayed by measurement of D-(-)-lactate levels in plasma. RESULTS: In I/R-PN group, extensive epithelial atrophy was observed, mucosal thickness, villous height, crypt depth and villous surface area were decreased significantly compared with PN group, whereas these findings did not occur in the I/R-Gln group. The incidence of intestinal bacterial translocation to spleen, liver, MLN, and blood was significantly higher in I/R-PN group than that in other groups. Plasma endotoxin levels significantly increased in the I/R-PN group compared with the I/R-Gln group. Remarkably higher values of D-(-)-lactate were also detected in PN group compared with that in I/R-Gln group. CONCLUSION: Glutamine protects the morphology and function of intestinal mucosa from injury after I/R in rats.     

Dietary Glutamine Supplementation Prevents Mucosal Injury and Modulates Intestinal Epithelial Restitution Following Ischemia-Reperfusion Injury in the Rat

The aim of the present study was to evaluate the preventive effect of a 2-day oral glutamine supplementation against intestinal ischemia-reperfusion (IR) injury in a rat. Male Sprague-Dawley rats were divided into four experimental groups: sham rats underwent laparotomy, sham-GLU rats underwent laparotomy and were treaded with enteral glutamine (GLU) given in drinking water (2%) 48 hr before and following operation, IR rats underwent occlusion of both the superior mesenteric artery and the portal vein for 30 min followed by 24 hr of reperfusion, and IR-GLU rats were treated with enteral glutamine 48 hr before and following IR. Intestinal mucosal damage (Park’s injury score), mucosal structural changes, enterocyte proliferation, and enterocyte apoptosis were determined 24 hr following IR. Sham-GLU rats demonstrated a lower rate of cell apoptosis in jejunum and ileum compared to sham animals. IR-GLU animals demonstrated a greater jejunal and ileal bowel and mucosal weight, mucosal DNA, villous height and crypt depth, and enterocyte proliferation index in ileum and a lower injury score grade in jejunum compared to IR-nontreated rats. In conclusion, pretreatment with oral glutamine prevents mucosal injury and improves intestinal recovery following IR injury in the rat.     

谷氨酰胺对NAFLD大鼠肠道紧密连接蛋白表达与定位的影响

目的：探讨谷氨酰胺对非酒精性脂肪性肝病（NAFLD）大鼠肠黏膜上皮细胞紧密连接蛋白的调控,及其对大鼠肠黏膜屏障的保护作用。方法建立NAFLD大鼠模型。实验分为正常组、模型组和谷氨酰胺组各12只,以第8周和第12周为时间点,观察肝脏病理学改变、记录肝指数,鲎试剂终点比色法检测内毒素水平,ELISA法测定TNF-α,westernblot法检测肠道occludin蛋白量,免疫组化染色明确蛋白定位及分布。结果病理证实高脂饮食诱导NAFLD鼠模成功。在第8周模型组和谷氨酰胺组肝指数、内毒素及TNF-α含量均高于正常组（3．14±0．76,3．07±0．65比2．84±0．55;0．213±0．019,0．194±0．010比0．120±0．014;25．76±3．54,23．65±2．78比7．84±1．55）;模型组和谷氨酰胺组差异无统计学意义（P＞0．05）。第12周时,与正常组比较,模型组和谷氨酰胺组上述指标升高明显（3．75±0．56,3．47±0．73比2．75±0．91;0．279±0．033,0．203±0．012比0．114±0．021;29．73±5．34,28．77±3．61比6．84±1．87,均P＜0．05）;谷氨酰胺治疗后血清内毒素水平的下降与模型组相比,差异有统计学意义（P＜0．05）。NAFLD大鼠存在肠道occludin蛋白量减少,谷氨酰胺具有上调其表达的作用。3组中occludin蛋白定位无明显区别,但其棕褐色染色强度及范围在正常组及谷氨酰胺组更强。结论谷氨酰胺能修复NAFLD大鼠肠黏膜屏障,其机制与降低TNF-α含量、上调肠上皮细胞紧密连接蛋白occludin的表达,进而改善内毒素血症等有关。     

Pectin-Supplemented Enteral Diet Reduces the Severity of Methotrexate-Induced Enterocolitis in Rats

Background: Administration of methotrexate (MTX) to rats fed an elemental diet results in a high mortality from severe enterocolitis. Previous studies have shown that pectin is an important precursor of substrates for intestinal structure and function and may facilitate intestinal recovery after enterocolitis. The aim of this study is to evaluate the effect of pectin on MTX-induced enterocolitis in rats. Methods: Rats received intragastric infusion of either 1% pectin-supplemented or pectin-free elemental diet from the beginning of the study via a gastrostomy. On the 4th day animals received either MTX, 20 mg/kg intraperitoneally, or saline injection and were killed on the 7th day for sampling. Results: Pectin supplementation significantly decreased body weight loss, organ water content, and intestinal myeloperoxidase levels and increased mucosal protein, DNA, and RNA content in enterocolitis rats. The intestinal permeability was increased by administration of MTX, and pectin supplementation significantly reversed the increased permeability in the distal small bowel and colon. Pectin supplementation also lowered the magnitude of bacterial translocation, decreased plasma endotoxin levels, and restored bowel microecology. Conclusions: Pectin significantly decreased MTX-induced intestinal injury and improved bowel integrity.     

谷氨酰胺对脓毒症大鼠急性肠道功能障碍的保护作用

目的 探讨谷氨酰胺对脓毒症大鼠急性肠道功能障的保护作用。方法S 将SD大鼠随机分为3组,即正常组(A组),模型组(B组)及谷氨酰胺组(C组), 模型组及谷氨酰胺组大鼠腹腔注射0.45mg/ml的LPS溶液,1ml/100g,即4.5mg/Kg,10分钟内分3次注射完毕进行造模。模型组造模后12小时给予5次/天灌注百普素溶液灌胃;谷氨酰胺组造模后12小时给予5次/天灌注百普素溶液,浓度为25.2％(80 kcal),每次4ml,另灌胃谷氨酰胺3.75g/Kg/d。模型组随机分为喂养36小时组(B1组)和喂养72小时组(B2组)。对各组进行组织病理观察,同时检测各组肠组织谷氨酰胺浓度。结果1. 模型36小时组、模型72小时组肠组织谷氨酰胺浓度低于正常组(P<0.05);模型36小时组、模型72小时组、谷氨酰胺组肠黏膜Chiu氏评分、绒毛长度及黏膜层厚度与正常组比较差异有统计学意义(P<0.05);模型组肠黏膜组织超微结构变化较谷氨酰胺组明显。2. 谷氨酰胺组肠组织谷氨酰胺浓度较模型36小时组、模型72小时组升高(P<0.05);谷氨酰胺组肠组织超微结构变化较模型组不同程度减轻。结论S脓毒症大鼠肠组织谷氨酰胺浓度下降,存在肠功能障碍,给予谷氨酰胺后急性肠道功能障得到保护。     

谷氨酰胺对急性胰腺炎大鼠肠黏膜胰岛素样生长因子表达及肠黏膜屏障的影响

目的 观察急性坏死性胰腺炎（ANP）时肠黏膜屏障的损伤情况,以及谷氨酰胺（Gln）和胰岛素样生长因子（IGF）对肠黏膜屏障的保护作用.方法 成功诱导ANP模型雄性Wistar大鼠48只,随机分为ANP组和Gln组各24只,另取假手术组24只作为对照.Gln组每日以Gln灌胃2次,剂量为1.5g/（kg·d）;ANP组和假手术组以同等量的生理盐水灌胃.分别在模型制作术后3、6、24、48 h时间点杀死大鼠,取胰头和末端回肠3～5 cm放入液氮中保存.观察胰腺和肠黏膜组织形态学改变,测定肠黏膜中IGF-1的表达、血清中二氨氧化酶（DAO）活性和内毒素浓度.结果 ANP组大鼠肠黏膜屏障功能严重破坏,肠道通透性明显增加,肠黏膜损伤评分明显增加;血清内毒素浓度、DAO活性明显升高（P均＜0.01）.与ANP组比较,Gln组动物肠黏膜损伤减轻,损伤评分有所下降,血清内毒素水平、DAO活性下降（P均＜0.05）.ANP组IGF-1表达水平明显下降（P ＜0.05）;Gln组明显升高（P＜0.05）,同时肠黏膜屏障功能得到一定的改善.结论 ANP时肠黏膜屏障结构和功能存在严重破坏;Gln能一定程度上减轻肠黏膜屏障损伤并能维护其功能;IGF-1参与Gln对ANP肠黏膜屏障损伤的修复和维持.     

Lansoprazole ameliorates intestinal mucosal damage induced by ischemia-reperfusion in rats

AIM:To investigate the protective effect of lansoprazoleon ischemia and reperfusion(I/R)-induced rat intestinalmucosal injury in vivo.METHODS:Intestinal damage was induced by clampingboth the superior mesenteric artery and the celiac trunkfor 30 rain followed by reperfusion in male Sprague-Dawleyrats.Lansoprazole was given to rats intraperitoneally 1 hbefore vascular clamping.RESULTS:Both the intraluminal hemoglobin and proteinlevels,as indices of mucosal damage,significantlyincreased in I/R-groups comparion with those of sham-operation groups.These increases in intraluminal hemoglobinand protein levels were significantly inhibited by the treatmentwith lansoprazole at a dose of 1 mg/kg.Small intestineexposed to I/R resulted in mucosal inflammation that wascharacterized by significant increases in thiobarbituric acid-reactive substances(TBARS),tissue-associatedmyeloperoxidase activity(MPO),and mucosal content of ratcytokine-induced neutrophil chemoattractant-1(CINC-1).These increases in TBARS,MPO activities and CINC-1 contentin the intestinal mucosa after I/R were all inhibited bypretreatment with lansoprazole at a dose of 1 mg/kg.Furthermore,the CINC-1 mRNA expression was increasedduring intestinal I/R,and this increase in mRNA expressionwas inhibited by treatment with lansoprazole.CONCLUSION:Lansoprazole inhibits lipid peroxidation andreduces development of intestinal mucosal inflammationinduced by I/R in rats,suggesting that lansoprazole mayhave a therapeutic potential for I/R injury.     

Protective effects of terminal ileostomy against bacterial translocation in a rat model of intestinal ischemia/reperfusion injury

AIM: To investigate the effects of terminal ileostomy on bacterial translocation (BT) and systemic inflammation after intestinal ischemia/reperfusion (I/R) injury in rats.METHODS: Thirty-two rats were assigned to either the sham-operated group, I/R group, I/R + resection and anastomosis group, or the I/R + ileostomy group. The superior mesenteric artery was occluded for 60 min. After 4 h, tissue samples were collected for analysis. BT was assessed by bacteriologic cultures, intestinal permeability and serum levels of endotoxin; systemic inflammation was assessed by serum levels of tumor necrosis factor (TNF)-α, interleukin (IL)-6 and IL-10, as well as by the activity of myeloperoxidase (MPO) and by intestinal histopathology.RESULTS: Intestinal I/R injury not only caused morphologic damage to ileal mucosa, but also induced BT, increased MPO activity and promoted the release of TNF-α, IL-6, and IL-10 in serum. BT and ileal mucosa injuries were significantly improved and levels of TNF-α and IL-6 in serum were decreased in the I/R + ileostomy group compared with the I/R + resection and anastomosis group.CONCLUSION: Terminal ileostomy can prevent the detrimental effects of intestinal I/R injury on BT, intestinal tissue, and inflammation.     

Lansoprazole ameliorates intestinal mucosal damage induced by ischemia-reperfusion in rats

AIM: To investigate the protective effect of lansoprazole on ischemia and reperfusion (I/R)-induced rat intestinal mucosal injury in vivo. METHODS: Intestinal damage was induced by clamping both the superior mesenteric artery and the celiac trunk for 30 min followed by reperfusion in male Sprague-Dawley rats. Lansoprazole was given to rats intraperitoneally 1 h before vascular clamping. RESULTS: Both the intraluminal hemoglobin and protein levels, as indices of mucosal damage, significantly increased in I/R-groups comparison with those of sham-operation groups. These increases in intraluminal hemoglobin and protein levels were significantly inhibited by the treatment with lansoprazole at a dose of 1 mg/kg. Small intestine exposed to I/R resulted in mucosal inflammation that was characterized by significant increases in thiobarbituric acid-reactive substances (TBARS), tissue-associated myeloperoxidase activity (MPO), and mucosal content of rat cytokine-induced neutrophil chemoattractant-1 (CINC-1). These increases in TBARS, MPO activities and CINC-1 content in the intestinal mucosa after I/R were all inhibited by pretreatment with lansoprazole at a dose of 1 mg/kg. Furthermore, the CINC-1 mRNA expression was increased during intestinal I/R, and this increase in mRNA expression was inhibited by treatment with lansoprazole. CONCLUSION: Lansoprazole inhibits lipid peroxidation and reduces development of intestinal mucosal inflammation induced by I/R in rats, suggesting that lansoprazole may have a therapeutic potential for I/R injury.     

Preventive effect of glutamine on intestinal barrier dysfunction induced by severe trauma

AIM: To investigate the mechanism underlying intestinalbarrier function damage after severe trauma and thetherapeutic effect of glutamine.METHODS: Burned patients, and animal models of severstrauma replicated by hemorrhagic shock combined withendotoxin infusion and burn injury, were included in a serialexperiment. Effects of oral glutamine on intestinal barrierfunction were observed in scalded rets. Parametersmeasured in these experiments were as follows: plasmalevels of diamine oxidase (DAO), tumor necrosis factor(TNFα), endotoxin (LPS), and lactate as well as D-lactateby biochemical methods, lactose/mannitol (L/M) ratio inurine by SP-3400, and pathological examination of intestinalmucosa under light microscopy.RESULTS: Plasma DAO activity was significantly increasedafter injury. There was a negative correlation betweenplasma DAO and intestinal mucosal DAO or pHi ( r= -0.93,plasma 0.80 ± 0.93,2.83 ± 1.71, 1.14 ± 0.64,2.36 ± 2.06 and2.49± 1.67 vs intestinal 0.52± 0.12,0.34 ± 0.03,0.45 ± 0.18,0.37± 0.26 and 0.41 ± 0.07; r = - 0.533, plasma 0.87 ± 0.75,1.89± 1.13, 1.21 ± 0.23,3.03 ± 2.61 and 4.70 ± 1.22 Vs pHi7.03± 0.05,7.05 ± 0.06,7.14 ± 0.096,7.20 ± 0.08 and 7.05 ±0.07; P ＜ 0.01-0.05). Positive correlations were foundbetween DAO activity and plasma TNFα, LPS, lactate, L/Mand D-lactate ( r = 0.817, 0.842, 0.872, and 0.951; plasmaDAO 0.87 ± 0.75,1.89 ± 1.13, 1.21 ± 0.23,3.03 ± 2.61 and 4.70± 1.22 vs TNF 0.08 ± 0.02,0.03 ± 0.25,0.17 ± 0.09,0.34 ± 0.15and 0.33 ± 0.18; vs LPS 0.14 ± 0.03,0.16 ± 0.04,0.21 ± 0.02,0.18± 0.16 and 0.37 ± 0.10; vs lactate 9.03 ± 2.19, 18.30 ±2.56,9.81 ± 2.83,12.01 ± 6.83, 12.01 ± 6.84 and 43.61 ± 11.27;vs L/M 0.03 ± 0.01,0.41 ± 0.27,0.62 ± 0.20, 1.70 ± 0.60; r =0.774, plasma DAO 1.25 ± 0.41,2.17 ± 0.71,2.29 ± 0.87, 1.23± 0.55 and 1.11 ± 0.47 vs D-lactate 8.37 ± 2.48, 18.25 ± 6.18,13.96 ± 4.94, 8.93 ± 3.00 and 12.39 ± 4.94; all P ＜ 0.01),repestively. Damage of intestinal mucosa was found bypathological examination. Intestinal barrier function wasimproved to a certain extent by oral glutamine in scaldedrats.CONCLUSION: Intestinal barrier function was damaged in theearly stage after trauma. Plasma DAO activity, D-lactatecontent, intestinal pHi and urine L/M may be sensitivemarkers of intestinal mechanical injury, and glutamine mayprotect against intestinal barrier dysfunction after severetrauma.     

Effect of cisapride on intestinal bacterial and endotoxin translocation in cirrhosis

AIM: To investigate the effects of cisapride on intestinal bacterial overgrowth (IBO), bacterial and endotoxin translocation, intestinal transit and permeability in cirrhotic rats. METHODS: All animals were assessed with variables including bacterial and endotoxin translocation, intestinal bacterial overgrowth, intestinal transit and permeability. Bacterial translocation (BT) was assessed by bacterial culture of MLN, liver and spleen, IBO by a jejunal bacterial count of the specific organism, intestinal permeability by determination of the 24-hour urinary (99m)Tc-DTPA excretion and intestinal transit by measurement of the distribution of (51)Cr in the intestine. RESULTS: Bacterial translocation (BT) and IBO was found in 48 % and 80 % cirrhotic rats respectively and none in control rats. Urinary excretion of (99m)Tc-DTPA in cirrhotic rats with BT (22.2+/-7.8) was greater than these without BT (10.5+/-2.9). Intestinal transit (geometric center ratio) was significantly delayed in cirrhotic rats (0.31+/-0.06) and further more delayed in cirrhotic rats with BT (0.24+/-0.06) than these without BT (0.38+/-0.11). Cirrhotic rats with IBO had significantly higher rates of intestinal bacterial and endotoxin translocation, slower intestinal transit time and higher intestinal permeability than those without IBO. It was also found that BT was closely associated with IBO and the injury of intestinal barrier. Compared with the placebo group, cisapride-treated rats had lower rates of bacterial/endotoxin translocation and IBO, which was closely associated with increased intestinal transit and improved intestinal permeability by cisapride. CONCLUSION: These results indicate that endotoxin and bacterial translocation in cirrhotic rats may be attributed to IBO and increased intestinal permeability. Cisapride that accelerates intestinal transit and improve intestinal permeability might be helpful in preventing intestinal bacterial and endotoxin translocation.     

Alterations of intestinal immune function and regulatory effects of L-arginine in experimental severe acute pancreatitis rats

ABM: To discuss the changes of intestinal mucosal immune function in rats with experimental severe acute pancreatitis (SAP) and the regulatory effect of L-arginine. METHODS: Male adult Wistar rats were randomly divided into pancreatitis group, sham-operation group, and L-arginine treatment group. Animals were killed at 24, 48, and 72 h after SAP models were developed and specimens were harvested. Endotoxin concentration in portal vein was determined by limulus endotoxin analysis kit. CD3+, CD4+, CD8+ T lymphocytes in intestinal mucosal lamina propria were examined by immunohistochemistry. Secretory immunoglobulin A (SIgA) in cecum feces was examined by radioimmunoassay. RESULTS: Compared to the control group, plasma endotoxin concentration in the portal vein increased, percentage of CD3+ and CD4+ T lymphocyte subsets in the end of intestinal mucosal lamina propria reduced significantly, CD4+/CD8+ ratio decreased, and SIgA concentrations in cecum feces reduced at 24, 48, and 72 h after SAP developed. Compared to SAP group, the L-arginine treatment group had a lower level of plasma endotoxin concentration in the portal vein, a higher CD3+ and CD4+ T lymphocyte percentage in the end of intestinal mucosal lamina propria, an increased ratio of CD4+/CD8+ and a higher SIgA concentration in cecum feces. CONCLUSION: Intestinal immune suppression occurs in the early stage of SAP rats, which may be the main reason for bacterial and endotoxin translocation. L-arginine can improve the intestinal immunity and reduce bacterial and endotoxin translocation in SAP rats.     

The preliminary experimental and clinical study of the relationship between the pigment gallstone and intestinal mucosal barrier

Aims:  To investigate the relations between the formation of pigment gallstone and the function of the intestinal mucosal barrier, as well as the underlying mechanism.
Methods:  Eighty guinea pigs were randomly divided into three groups in which they were respectively given normal diet, gallstone-causing diet, and gallstone-formation diet with a supplementary intestinal mucosal protection compound known as glutamine. The model of pigment gallstone was established after 8 weeks of dietary administration. Indices about the function of the intestinal mucosal barrier and bacterial translocation were measured. Clinical cases were divided into three groups: control, cholesterol gallstone, and pigment gallstone, where the levels of plasma diamine oxidase (DAO), plasma endotoxin and the excretion rates of technetium 99m-diethylene triamine pentaacetic acid (99mTC-DTPA) in the urine of each group were measured.
Results:  In the pigment gallstone group, the level of plasma DAO and endotoxin, the excretory ratio of lactulose and mannitol in urine, the bacterial translocation ratio in the celiac lymph nodes and the activities of β-glucuronidase increased comparing to the control group. The gallstone-formation rate for the intestinal mucosal protection group (GLN) decreased, and other indices, except the activity of β-glucuronidase, were all lower than that of gallstone-formation group. In the clinical experiment, the levels of plasma DAO and endotoxin, as well as the excretory rate of 99mTC-DTPA in urine were higher in the patients with gallstones than that in the control group.
Conclusions:  The formation of pigment gallstone was related to the abnormal function of the intestinal mucosal barrier. The abnormality in the function of the intestinal mucosal barrier probably induced the formation of gallstone by a bacterial translocation mechanism.     

Tumor necrosis factor-α mediates JNK activation response to intestinal ischemia-reperfusion injury

AIM:To investigate whether tumor necrosis factor-α(TNF-α)mediates ischemia-reperfusion(I/R)-induced intestinal mucosal injury through c-Jun N-terminal kinase(JNK)activation.METHODS:In this study,intestinal I/R was induced by 60-min occlusion of the superior mesenteric artery in rats followed by 60-min reperfusion,and the rats were pretreated with a TNF-α inhibitor,pentoxifylline,or the TNF-α antibody infliximab.After surgery,part of the intestine was collected for histological analysis.The mucosal layer was harvested for RNA and protein extraction,which were used for further real-time polymerase chain reaction,enzyme-linked immunosorbent assay and Western blotting analyses.The TNF-α expression,intestinal mucosal injury,cell apoptosis,activation of apoptotic protein and JNK signaling pathway were analyzed.RESULTS:I/R significantly enhanced expression of mucosal TNF-α at both the mRNA and protein levels,induced severe mucosal injury and cell apoptosis,activated caspase-9/caspase-3,and activated the JNK signaling pathway.Pretreatment with pentoxifylline markedly downregulated TNF-α at both the mRNA and protein levels,whereas infliximab pretreatment did not affect the expression of TNF-α induced by I/R.However,pretreatment with pentoxifylline or infliximab dramatically suppressed I/R-induced mucosal injury and cell apoptosis and significantly inhibited the activation of caspase-9/3 and JNK signaling.CONCLUSION:The results indicate there was a TNFα-mediated JNK activation response to intestinal I/R injury.     

鲜生地汁对大鼠肠缺血再灌注损伤的防护作用

目的:探讨鲜生地汁对大鼠肠缺血再灌注损伤(I/R)的防护作用及其机制。方法:采用肠系膜上动脉(SMA)夹闭方法制作I/R模型。实验大鼠随机分为正常组、I/R模型组、I/R 鲜生地汁大剂量组、I/R 鲜生地汁小剂量组、I/R 乳果糖组。观察肠系膜上动脉夹闭0.5小时再灌注24小时、48小时、72小时后肠黏膜损伤程度,测定血浆内毒素水平。结果:各时点I/R 鲜生地汁大剂量、I/R 小剂量组及I/R 乳果糖组肠黏膜损伤程度、血浆内毒素水平均低于I/R模型组(P<0.05)。结论:鲜生地汁对肠缺血再灌注损伤大鼠肠黏膜具有保护作用。     

Prophylactic administration of L-arginine improves the intestinal barrier function after mesenteric ischaemia.

BACKGROUND: Ischaemia/reperfusion (I/R) of the intestine causes mucosal injury associated with a high death rate in rats. AIM: To investigate whether nitric oxide (NO) might be implicated in the recovery of the intestinal mucosa after ischaemic insult. METHODS: Wistar rats were subjected to mesenteric artery occlusion for 90 minutes. The animals were given either L-arginine, the substrate of NO synthase, or molsidomine, a NO donor. The controls received casein hydrolysate. The compounds were administered by gavage 19, 16, and 1.5 hours before ischaemia. Mucosal barrier permeability and cGMP content were determined 24 hours after ischaemia. RESULTS: Survival after I/R was 50% in the control group. Animals treated with L-arginine or molsidomine exhibited a higher survival rate (70% and 83% respectively). Mucosal barrier permeability was decreased in rats receiving L-arginine or molsidomine compared with controls (4.0 (0.9) and 2.6 (0.6) v 11.2 (1.6) 14C-PEG pmol/segment, p < 0.05). Increased cGMP content was seen in the mucosa of the L-arginine group. CONCLUSION: The findings suggest that pretreatment with L-arginine or molsidomine ameliorates survival after intestinal I/R and improves mucosal barrier function.     

terbal cardiotonic pills prevent gut ischemia／reperfusion-induced hepatic microvascular dysfunction in rats fed ethanol chronically

AIM: Cardiotonic Pill (CP), an oral herbal medicine that includes Danshen (Salviae Miltiorrhizae), Panax notoginseny and Dyroblanops aromatica gaettn, has been clinically used for vascular diseases such as occlusive vasculitis, coronary diseases, atherosclerosis, and cerebral infarction. The main component, Salviae Miltiorrhizae, has been reported to prevent cerebral and intestinal reperfusion injury. However, little is known about the effect of CP on hepatic microcirculation. Thus, this study aimed to determine whether CP could affect hepatic microvascular dysfunction elicited by gut ischemia/ reperfusion (I/R) in rats fed ethanol chronically. METHODS: Male Wistar rats were pair-fed with a liquid diet containing ethanol or isocaloric control diet for 6 wk. After laparotomy, one lobe of the liver was examined through an inverted intravital microscope. The rats were exposed to 30 min of gut ischemia followed by 60 min of reperfusion. Rhodamine-6G-labeled leukocytes in the sinusoids were observed 90 min after the onset of superior mesenteric artery occlusion. Plasma tumor necrosis factor (TNF)-α and endotoxin levels were measured 1 h after the onset of reperfusion. Plasma alanine aminotransferase (ALT) activities were measured 6 h after the onset of reperfusion. In another set of experiments, CP (0.8 g/kg, intragastrically) was administered 1 and 24 h before the onset of ischemia. RESULTS: In control rats, gut I/R elicited increases in the number of stationary leukocytes, and plasma TNF-α and endotoxin levels and plasma ALT activities. These changes were mitigated by pretreatment with CP. In ethanol-fed rats, the gut I/R-induced increases in the number of stationary leukocytes, plasma endotoxin levels and ALT activities were enhanced. Pretreatment with CP attenuated the enhancement of gut I/R-induced responses by chronic ethanol consumption. CONCLUSION: These results suggest that CP prevents the gut I/R-induced hepatic microvascular dysfunction and hepatocellular injury. A reduction of inflammatory responses such as TNF-α production via reduction of blood endotoxin levels appears to be involved in the mechanisms. Chronic ethanol consumption enhances gut I/R-induced hepatic microvascular and hepatocellular injury. CP also attenuates an enhancement of gut I/R-induced responses by chronic ethanol consumption via the reduction of blood endotoxin levels.     

Glutamine prevents oxidative stress in a model of mesenteric ischemia and reperfusion

AIM: To evaluate preventative effects of glutamine in an animal model of gut ischemia/reperfusion (I/R).METHODS: Male Wistar rats were housed in a controlled environment and allowed access to food and water ad libitum. Twenty male Wistar rats were divided into four experimental groups: (1) control group (control) - rats underwent exploratory laparotomy; (2) control + glutamine group (control-GLU) - rats were subjected to laparotomy and treated intraperitoneally with glutamine 24 and 48 h prior to surgery; (3) I/R group - rats were subjected to occlusion of the superior mesenteric artery for 30 min followed by 15 min of reperfusion; and (4) ischemia/reperfusion + glutamine group (G + I/R) - rats were treated intraperitoneally with glutamine 24 and 48 h before I/R. Local and systemic injuries were determined by evaluating intestinal and lung segments for oxidative stress using lipid peroxidation and the activity of superoxide dismutase (SOD), interleukin-6 (IL-6) and nuclear factor kappa beta (NF-κB) after mesenteric I/R.RESULTS: Lipid peroxidation of the membrane was increased in the animals subjected to I/R (P < 0.05). However, the group that received glutamine 24 and 48 h before the I/R procedure showed levels of lipid peroxidation similar to the control groups (P < 0.05). The activity of the antioxidant enzyme SOD was decreased in the gut of animals subjected to I/R when compared with the control group of animals not subjected to I/R (P < 0.05). However, the group that received glutamine 24 and 48 h before I/R showed similar SOD activity to both control groups not subjected to I/R (P < 0.05). The mean area of NF-κB staining for each of the control groups was similar. The I/R group showed the largest area of staining for NF-κB. The G + I/R group had the second highest amount of staining, but the mean value was much lower than that of the I/R group (P < 0.05). For IL-6, control and control-GLU groups showed similar areas of staining. The I/R group contained the largest area of IL-6 staining, followed by the G + I/R animals; however, this area was significantly lower than that of the group that underwent I/R without glutamine (P < 0.05).CONCLUSION: These results demonstrate that pretreatment with glutamine prevents mucosal injury and improves gut and lung recovery after I/R injury in rats.     

Massive intestinal resection in rats fed up on glutamine: hepatic glycogen content valuation

BACKGROUND: Glutamine has been widely used in treatment of small bowel syndrome and its metabolic effects on the small intestine are well known, however, it has been little studied its effects on hepatic metabolism under this condition. AIM: To verify through experimental model, a glutamine based supplemental diet, administered via oral to rats submitted to massive intestinal resection, evaluating weight evolution and hepatic glycogen content. MATERIAL AND METHODS: Male rats, Wistar, were allocated into three groups to undergo enterectomy. Following diets were applied: with glutamine (G group), without glutamine (NG group), and standard diet from the laboratory (R group). All animals had massive small intestine resection including ileocecal valve removal. After 20 days, all animals were sacrificed. The liver was removed to histological analysis by light microscopy. Slides were stained by periodic acid of Schiff with diastasis. RESULTS: All animals lost weight from the beginning to the end of experiment. Comparing weight loss average expressed in percentage, there was no difference statistically significant on this variance. In analyzed groups, the hepatic glycogen content did not differ statistically, in the histological method evaluated. CONCLUSION: Glutamine feeding via oral did not influence weight loss reduction of animal submitted to massive intestinal resection and did not stimulate glycogen synthesis and storage into hepatocytes.