The Effects of Nitric Oxide Supplementation and Inhibition on Bacterial Translocation in Bile Duct Ligated Rats

Obstructive jaundice promotes bacterial translocation from the gut, but the role of nitric oxide is controversial in this process. We studied the effects of nitric oxide synthase substrate, L-arginine, and nitric oxide synthase inhibitor, NG-nitro-¿-arginine methyl ester, on bacterial translocation in bile duct ligated rats. The animals were randomized into five groups; control, sham, common bile duct ligation alone, nitric oxide inhibition, and nitric oxide supplementation. Obstructive jaundice was performed with common bile duct ligation. ¿-arginine or NG-nitro-¿-arginine methyl ester was injected once daily for 14 days. Blood bilirubin level, liver histology, and bacterial translocation to the mesenteric lymph nodes as well as to the liver were assessed. The ¿-arginine supplemented group had the lowest bacterial translocation rate, but the most prominent hepatic fibrosis. Nitric oxide inhibition increased bacterial translocation to the mesenteric lymph nodes. Therefore, the administration of nitric oxide donor or inhibitor acts as a significant regulatory factor for bacterial translocation in obstructive jaundice.     

一氧化氮在梗阻性黄疸大鼠肝、肾、肠组织中含量变化及意义

目的 了解一氧化氮（NO）在梗阻性黄疸大鼠肝、肾、肠组织中含量变化及意义。方法 大鼠胆总管结扎后,分别于第一周内和第三周内应用Aminoguanidine（AG）抑制NO合成,同时应用生理盐水（NS）作对照,检测不同时段抑制NO合成后大鼠肝、肾、肠组织中NO和丙二醛（MDA）含量、肌酐清除率（Ccr）血清总胆红素（T-BIL）和丙氨酸氨基转移酶（ALT）含量及肠系膜淋巴结细菌移位（BT）率的变化。结果 胆总管结扎后,大鼠肝、肾、肠组织中NO含量明显升高,在胆总管结扎第一周抑制NO合成后,肝、肾、肠组织中NO含量明显下降,MDA含量明显升高,血ALT明显升高、Ccr明显下降、肠系膜淋巴结BT率明显升高;而在胆总管结扎第三周抑制NO合成后,肝、肾、肠组织中NO和MDA含量明显下降,血ALT明显下降、Ccr明显升高。肠系膜淋巴结BT率明显下降。结论NO在胆道梗阻引起的肝、肾、肠粘膜屏障功能障碍的发生机制中具有重要作用,既有保护作用,又有损害作用。梗阻早期表现为对组织的保护作用,后期表现为对组织的损害作用。     

The Effect of Biliary Decompression on Bacterial Translocation in Jaundiced Rats

Patients with obstructive jaundice are prone to septic complications after biliary tract operations. Restoring bile flow to the intestine may help to decrease the complication rate. The present study is aimed at evaluating the effect of biliary decompression on bacterial translocation in jaundiced rats.Sixty-six male Sprague-Dawley rats were randomly allocated to six groups subjected to common bile duct ligation (CBDL) and transection (groups 2–6) or sham operation (group 1). In groups and 2 the incidence of enteric bacterial translocation was determined 2 weeks after sham operation or CBDL. In groups 3–6, biliary decompression was achieved by performing a choledochoduodenostomy after 2 weeks of biliary decompression. Bacterial translocation was then studied 1,2,3 and 5 weeks following biliary decompression.The rate of bacterial translocation to mesenteric lymph nodes in obstructive jaundice was significantly higher as compared with controls, and decreased with time to nil three weeks following biliary decompression. The incidence of bacterial translocation was closely correlated (r = 0.844; p = 0.034) with serum alkaline phosphatase activity and seemed to fit with the morphological changes noted in the small intestine. The decrease in bacterial translocation, however, lags behind the recovery of liver function as measured by routine liver function tests and antipyrine clearance.Obstructive jaundice thus promotes bacterial translocation in the rat. Biliary decompression gradually decreases the rate of bacterial translocation.     

Does pharmaconutrition with L-arginine and/or alpha-tocopherol improve the gut barrier in bile duct ligated rats?

BACKGROUND/AIM: Nitric oxide supplementation and antioxidant therapy modulate gut barrier function, but the relationships between enhanced nitric oxide production, antioxidant administration, and biliary obstruction remain unclear. We evaluated the role of nitric oxide and alpha-tocopherol supplementation in bile duct ligated rats. METHODS: Fifty male Wistar albino rats underwent sham operation (group I; control animals) or bile duct ligation (groups II, III, IV, and V). The ligation groups received the following regimens: standard pellet diet (group II), pellet diet plus intramuscularly administered alpha-tocopherol (group III), and L-arginine-enriched pellet diet without (group IV) or with (group V) alpha-tocopherol. Nitric oxide, malondialdehyde, and alpha-tocopherol concentrations were assessed at the end of 3 weeks. Liver and intestinal samples were scored histologically. Mesenteric lymph node and liver cultures were assessed for bacterial translocation. RESULTS: The liver malondialdehyde concentration was highest in group III. The nitric oxide content in the liver was higher in groups III and V, as were the blood alpha-tocopherol levels. Bacterial translocation was evident following bile duct ligation, but did not differ among the treatment groups. Intestinal histology revealed that group III had the lowest villus height, that group V had the least villus count, and that group II had the highest mucous cell count. The fibrosis scores were higher in groups IV and V. CONCLUSIONS: An obvious effect of alpha-tocopherol (with or without L-arginine) on the gut barrier could not be demonstrated. Moreover, the L-arginine-enriched diet promoted fibrosis in the liver. Thus, while biliary duct obstruction triggers bacterial translocation, nitric oxide and/or alpha-tocopherol supplementation did not seem to improve the gut barrier in our model.     

Effect of different enteral nutrients on bacterial translocation in experimental obstructive jaundice

Obstructive jaundice leads to bacterial translocation (BT) by disruption of the gut barrier, intestinal microecology, and impaired host immune defence. The objective of the present study is to investigate the effects of different enteral nutrients on BT that is induced by obstructive jaundice in rats. Eighty male Wistar-Albino rats were randomly assigned into 4 groups. Group 1: 20 rats underwent laparotomy, common bile duct (CBD) was not actually ligated and transected, but sham ligation of CBD was performed. Groups 2-4: 60 rats underwent laparotomy, CBD ligation and transection. Group 1 and 2 rats were given rat chow, group 3 rats were fed a glutamine and arginine supplemented enteral diet, and group 4 rats were fed an arginine, m-RNA and omega-3 supplemented enteral diet, an immunonutrient. Rats in groups 3 and 4 had significantly less BT to mesenteric lymph nodes compared to rats in group 2 (p = 0.001). These findings suggest that oral administration of an arginine and glutamine supplemented diet and immunonutrition reduce BT in rats with obstructive jaundice.     

Detrimental effects of nitric oxide on mesenteric circulation during endotoxaemia and its reversal by aminoguanidine.

OBJECTIVE: To investigate the effect of endotoxaemia on rat mesenteric vascular bed and plasma nitrite concentrations, the possible beneficial effect of aminoguanidine (the selective inducible nitric oxide synthase inhibitor) compared with N(G)-nitro-L-arginine methyl ester (L-NAME) (non-selective nitric oxide synthase inhibitor). DESIGN: Randomised experiment. SETTING: University surgical research laboratory, Turkey. SUBJECTS: 75 Wistar rats. INTERVENTIONS: Rats were divided into control (n = 30) and endotoxaemia (n = 42) groups. Endotoxaemia was produced by intraperitoneal injection of lipopolysaccharide 20 mg/kg. Subgroups were given either aminoguanidine or L-NAME. MAIN OUTCOME MEASURES: After 4 hours, isolated perfused mesenteric preparations were obtained and pressor responses to phenylephrine and vasodilatation responses to acetylcholine were evaluated, and plasma nitrite concentrations measured. RESULTS: Pressor response to phenylephrine did not alter but vasodilatation in response to acetylcholine was significantly reduced during endotoxaemia. Pretreatment with aminoguanidine prevented the impairment of the response to acetylcholine. However, L-NAME was ineffective. In the control group, aminoguanidine and L-NAME did not alter the vascular reactivity. The baseline plasma nitrite concentrations in the control group were increased 5-fold during endotoxaemia. This increase was significantly reduced with aminoguanidine but not with L-NAME. CONCLUSION: The protection achieved by aminoguanidine but not L-NAME suggested that nitric oxide produced by inducible nitric oxide synthase had a role in the impairment of endothelial response during endotoxaemia, and confirmed the importance of selective inducible nitric oxide synthase inhibition to achieve beneficial effects in endotoxaemia.     

Effect of nitric oxide on the hypoglycaemic phase of endotoxaemia

BACKGROUND: Depletion of liver glycogen stores and subsequent hypoglycaemia is one of the unresolved features in endotoxaemia. The aim of this study was to elucidate the effect of L-arginine treatment on the glucose requirement and impending liver damage during the hypoglycaemic period of endotoxaemia. METHODS: Sixty-three of 98 male Wistar rats were assigned equally to one of three groups and received saline as control, L-arginine as selective nitric oxide donor or N(G)-nitro-L-arginine methyl ester for non-selective inhibition of nitric oxide production 1 h before endotoxin injection. At 2, 4 and 6 h following endotoxin, blood and liver samples were collected. Plasma nitrite plus nitrate, glucose, insulin and glucagon concentrations and total liver-reduced glutathione were measured. Hepatocellular glycogen content and liver damage were assessed simultaneously by histological quantification. An additional seven rats were allocated to each group and subjected to i.v. glucose tolerance test during the hypoglycaemic period. RESULTS: Increased levels of endogenousglutathione (P = 0.003) and excess nitric oxide (P = 0.002) apparently protected the liver from endotoxin-induced injury by preserving the optimum glucose consumption rate, insulin/glucagon ratio and liver glycogen in L-arginine-plus-endotoxin-treated group. Furthermore, expected hypoglycaemic period was not observed in these animals. CONCLUSION: Exogenous L-arginine prevented the excessive liver glycogen release without inhibiting glucose consumption while decreasing hepatic injury during the expected hypoglycaemic phase of endotoxaemia.     

Nitric oxide-generating beta-adrenergic blocker nipradilol preserves postischemic cardiac function.

BACKGROUND: Preconditioning protects the heart from ischemic injury, but some of its effects are reversed by beta-adrenergic blockade. We hypothesize that because nitric oxide is known to precondition the heart, the nitric oxide-generating beta-blocker nipradilol may simultaneously precondition and provide clinically relevant beta-blockade. METHODS: Isolated, crystalloid-perfused rabbit hearts underwent 1 hour of left anterior descending coronary artery ischemia followed by 1 hour of reperfusion. Before ischemia, six hearts received nipradilol, six received the nitric oxide donor L-arginine, four hearts received the nitric oxide synthase inhibitor N(G)-nitro-L-arginine methyl ester before L-arginine, nine underwent ischemic preconditioning, and six received beta-blockade by esmolol before ischemic preconditioning. Seven hearts received no pretreatment (control). Action potential duration and ventricular pressure were measured. Infarct size was determined at the end of reperfusion. RESULTS: Both L-arginine and ischemic preconditioning prolonged action potential duration significantly at 60 minutes of reperfusion. Compared with control, infarct size was reduced by ischemic preconditioning (26%+/-4% versus 49%+/-3%, IPC versus control; p<0.01), L-arginine (24%+/-2%; p<0.01 versus control), and nipradilol (24%+/-2%; p<0.01 versus control). Only nipradilol preserved peak developed pressure during reperfusion. CONCLUSIONS: Despite its properties as a beta-adrenergic blocking agent, nipradilol was able to precondition the heart, probably as a result of its ability to produce nitric oxide.     

Tyrosine phosphorylation of a 38-kDa capacitation-associated buffalo (Bubalus bubalis) sperm protein is induced by L-arginine and regulated through a cAMP/PKA-independent pathway

The aim of the present study was to determine the effect of L-arginine on nitric oxide (NO*) synthesis, capacitation and protein tyrosine phosphorylation in buffalo spermatozoa. Ejaculated buffalo spermatozoa were capacitated in the absence or presence of heparin, or L-arginine or N(omega)-nitro-L-arginine methyl ester (L-NAME), an inhibitor of nitric oxide synthase (NOS) for 6 h. Capacitating spermatozoa generated NO* both spontaneously and following stimulation with L-arginine and L-NAME quenched such L-arginine-induced NO* production. Immunolocalization of NOS suggested for existence of constitutive NOS in buffalo spermatozoa. L-Arginine (10 mm) was found to be a potent capacitating agent and addition of L-NAME to the incubation media attenuated both L-arginine and heparin-induced capacitation and suggested that NO* is involved in the capacitation of buffalo spermatozoa. Two sperm proteins of M(r) 38 000 (p38) and 20 000 (p20) were tyrosine phosphorylated extensively by both heparin and L-arginine. Of these, the tyrosine phosphorylation of p38 was insensitive to both induction by cAMP agonists as well as inhibition by a protein kinase A (PKA) inhibitor. Further, most of these L-arginine-induced tyrosine phosphorylated proteins were localized to the midpiece and principal piece regions of flagellum of capacitated spermatozoa and suggested that sperm flagellum takes active part during capacitation. These results indicated that L-arginine induces capacitation of buffalo spermatozoa through NO* synthesis and tyrosine phosphorylation of specific sperm proteins involving a pathway independent of cAMP/PKA.     

The effect of platelet activating factor antagonist BN 52021 on bacterial translocation and ICAM-I expression in experimental obstructive jaundice.

Expression of intracellular adhesion molecule-1 (ICAM-1) in an obstructive jaundice model and the potential protective role of platelet activating factor antagonist over small intestine and liver together with its effects on bacterial translocation are examined in this study. Forty-eight male Wistar albino rats were assigned into four equal groups of 12. In groups I and II, animals were sham operated. In groups III and IV, common bile duct ligation and division were performed. In group I and group III, 0.5 ml/day normal saline was applied intraperitoneally daily from day 2 to 6 of the study; in group II and group IV, 1 mg/kg/day BN 52021 was applied intraperitoneally daily from day 2 to 6 of the study. All animals were sacrificed on postoperative day 7. ICAM-1 expression (CD54 positivity) was analyzed in the liver and ileum tissue by immunohistochemical method. Samples from blood, liver mesenteric lymph nodes, and spleen were cultured under aerobic conditions. It is revealed that ICAM-1 expression was statistically higher in group III, with highest bacterial translocation and liver and spleen injury when compared to other groups. Serum alanine transaminase (ALT), aspartate transaminase (AST), alkaline phosphatase (ALP), gamma-glutamyltranspeptidase (GGT), bilirubin, tumor necrosis factor alpha (TNFalpha), and interleukin 1beta(IL-1beta) values were at the highest level in group III, and there was a statistical decrease in group IV compared to group III. The administration of BN52021 in experimental obstructive jaundice is a useful way to reduce liver and intestinal mucosal villi damage by inhibiting bacterial translocation and systemic inflammatory response.     

Nitric oxide modulates water and electrolyte transport in the ileum.

OBJECTIVE: To test the hypothesis that nitric oxide is a modulator of ileal water and ion transport. SUMMARY BACKGROUND DATA: Nitric oxide is produced in the vascular endothelium and enteric neural plexuses of the intestine and is involved in gastrointestinal motility and smooth muscle contractility. Little is known about the role of nitric oxide in intestinal epithelial transport. METHODS: Ten-centimeter rabbit ileal segments (n = 50) were vascularly perfused with an electrolyte solution containing red cells. The lumen was perfused with a solution containing 14C-PEG. Net fluxes of water and ions were calculated during three 20-minute periods: basal, drug infusion, and recovery. Perfusion pressure was recorded to document changes in vascular resistance. Agents infused included the nitric oxide synthase substrate L-arginine, the nitric oxide source sodium nitroprusside, the substrate control D-arginine, and the nitric oxide synthase inhibitor NG-nitro-L-arginine methyl ester. RESULTS: L-arginine and sodium nitroprusside caused absorption of water and ions. NG-nitro-L-arginine methyl ester caused secretion of water and ions, which was prevented by synchronous infusion of L-arginine. Infusion of D-arginine had no effect. Both L-arginine and sodium nitroprusside caused mild vasodilation. CONCLUSIONS: Inhibition of endogenous nitric oxide synthesis by NG-nitro-L-arginine methyl ester causes secretion of water and ions. This secretion is reversed by administration of the nitric oxide synthase substrate L-arginine. These findings are consistent with the hypothesis that endogenous nitric oxide has a proabsorptive influence over the ileum in the basal state.     

Hypotension during septic shock does not correlate with plasma levels of nitric oxide metabolites in the conscious rat

Hypotension following administration of lipopolysaccharide may be due to excessive production of the potent vasodilator nitric oxide brought about by induction of nitric oxide synthase. The purpose of this study was to determine in conscious, fasted rats what role nitric oxide played in lipopolysaccharideinduced hypotension. When examined by Western immunoblot analysis, inducible nitric oxide synthase immunoreactivity was detected in the aorta at 3 hours and increased over time following administration of intraperitoneal lipopolysaccharide (20 mg/kg). When compared with saline-treated control rats, significant hypotension was observed at 2,4, and 6 hours following lipopolysaccharide treatment. Blood pressure at 2 hours did not differ significantly from that at 6 hours. Using the Griess reaction to quantify plasma levels of nitrates and nitrites as an index of systemic nitric oxide production, an augmentation in the formation of these nitric oxide metabolites was demonstrated at 4 and 6 hours but not at 2 hours. Subcutaneous administration of the nitric oxide synthase inhibitor N^G-nitro-L-arginine methyl ester (5 mg/kg) prevented lipopolysaccharide-induced hypotension, an effect reversed by subcutaneous L-arginine but not D-arginine (350 mg/kg). However, nitric oxide synthase inhibition did not attenuate the ability of lipopolysaccharide to increase plasma nitrate/nitrite levels. These data indicate that lipopolysaccharideinduced production of nitric oxide metabolites does not correlate with lipopolysaccharide-induced hypotension. Supported in part by Deutsche Forschungsgemeinschaft grant KL 931/1-2 (K.K.) and the Trauma Research Center, Houston, sponsored by National Institutes of Health grant GM 38529 (F.G.M.) Presented at the Thirty-Seventh Annual Meeting of The Society for Surgery of the Alimentary Tract, San Francisco, Calif., May 19–22, 1996.     

诱生型一氧化氮合酶在阻塞性黄疸肝损害中的调控作用

目的：通过体内、外实验，探讨诱生型一氧化氮合酶（iNOS）在阻塞性黄疸肝损害中的调控作用。方法：（1）　体外实验：采用胶原酶原位肝灌注法分离大鼠肝细胞，行原代培养后，用iNOS抑制剂SMT作用于肝细胞，50μmol/L 甘氨鹅脱氧胆酸钠(GCDC) 作用后用流式细胞术（FCM）及原位末端标记法（TUNEL）检测肝细胞凋亡情况。（2）体内实验：结扎大鼠胆总管, 结扎后3，7，14，21d, 分别用TUNEL法及免疫组化SABC法检测大鼠肝组织细胞凋亡状态及iNOS蛋白的表达。结果：（1） 随SMT浓度的增加，肝细胞的凋亡明显减少。（2）大鼠胆总管结扎后随结扎时间的延长细胞凋亡指数(AI)升高，结扎14d后AI达高峰。iNOS蛋白表达越强, 则AI越高。结论：iNOS参与阻塞性黄疸肝细胞凋亡的调节，并在阻塞性黄疸肝损害的发生和发展中起重要作用。     

Role of bile in intestinal barrier function and its inhibitory effect on bacterial translocation in obstructive jaundice in rats

BACKGROUND: Our previous study using genetically labeled Escherichia coli strain JNW14 revealed that obstructive jaundice promotes bacterial translocation in rats and that the absence of bile in the intestinal tract is considered to be a factor inducing bacterial translocation. The aim of this study was to investigate the role of bile and bile acids in intestinal barrier function against bacterial translocation. MATERIALS AND METHODS: Eight-week-old male specific-pathogen-free Wistar rats were subjected to ligation of their common bile ducts (CBDL). The CBDL rats were treated with bacitracin, neomycin sulfate, and streptomycin sulfate, and the intestinal tract was colonized with E. coli strain JNW14, which was genetically labeled with resistant markers against the above three antibiotics, to monitor the bacterial translocation. The rats were then administered saline, cholic acid (20 mg/100 g BW), taurocholic acid (TCA: 5-50 mg/100 BW), or bile (1.5-6 mL/day) via a duodenal catheter. The degree of bacterial translocation of E. coli strain JNW14 to the mesenteric lymph nodes was compared. Histopathological examination of the terminal ileum and intestinal permeability test using phenolsulfonphthalein was also performed. RESULTS: Both cholic acid and TCA showed no inhibitory effect on bacterial translocation at any of the doses tested in CBDL rats, although TCA significantly decreased the numbers of E. coli strain JNW14 in the cecum. However, bile administration reduced the numbers of E. coli strain JNW14 in the cecum and mesenteric lymph nodes in CBDL rats although the inhibitory effect was weak. The integrity and permeability of the intestinal mucosa were kept at normal levels by bile administration in CBDL rats whereas the morphological changes, such as villous atrophy, villous edema, and lacteal canal dilatation, were observed in other CBDL rats. CONCLUSION: Bile plays an important role in maintaining the intestinal barrier function to prevent the invasion of enteric bacteria to the underlying tissues, suggesting that the intestinal administration of bile to patients with obstructive jaundice is a useful way to reduce infectious complications by inhibiting bacterial translocation from the intestine to other organs.     

Nitric oxide prevents aldose reductase activation and sorbitol accumulation during diabetes

Increased glucose utilization by aldose reductase (AR) has been implicated in the development of diabetes complications. However, the mechanisms that regulate AR during diabetes remain unknown. Herein we report that several nitric oxide (NO) donors prevent ex vivo synthesis of sorbitol in erythrocytes obtained from diabetic or nondiabetic rats. Compared with erythrocytes of nondiabetic rats, the AR activity in the erythrocytes of diabetic rats was less sensitive to inhibition by NO donors or by AR inhibitors-sorbinil or tolrestat. Treatment with N(G)-nitro-L-arginine methyl ester (L-NAME), an inhibitor of NO synthesis, enhanced AR activity and sorbitol accumulation in tissues of nondiabetic rats. Application of transdermal nitroglycerin patches or treatment with L-arginine did not inhibit AR activity or sorbitol accumulation in the tissues of nondiabetic animals. Treatment with L-NAME increased, whereas treatment with L-arginine or nitroglycerine patches decreased AR activity and sorbitol content in tissues of diabetic rats. These observations suggest that NO maintains AR in an inactive state and that this repression is relieved in diabetic tissues. Thus, increasing NO availability may be a useful strategy for inhibiting the polyol pathway and preventing the development of diabetes complications.     

L-arginine-induced relaxation of the internal anal sphincter is not mediated by nitric oxide

BACKGROUND: Topical application of L-arginine, the precursor of nitric oxide, reduces resting anal pressure without significant side-effects and may therefore be of benefit in the treatment of anal fissure. This in vitro study investigated the effect of L-arginine on sheep and human isolated internal anal sphincter (IAS) to ascertain the role played by nitric oxide and guanosine 3',5'-cyclic monophosphate. METHODS: Strips of sheep and human IAS were mounted in isolated organ baths. The effects on myogenic tone of increasing concentrations of L-arginine, D-arginine and other amino acids were evaluated. RESULTS: L-Arginine, D-arginine and other basic amino acids (L-lysine and L-ornithine) all caused a concentration-dependent reduction in myogenic tone. L-Arginine was the most effective and produced a mean(s.e.m.) maximal reduction in myogenic tone of 78.2(7.1) and 40.2(9.3) per cent in sheep and human tissue respectively. These responses were not affected by N(G)-nitro-L-arginine methyl ester, a nitric oxide synthase inhibitor, or 1H-[1,2,4]oxadiazolo[4,3-a]-quinoxalin-1-one, an inhibitor of soluble guanylyl cyclase. Changes in pH per se were unable to explain the relaxation fully, but an equiosmolar sodium chloride solution produced a concentration-response relationship similar to that of L-arginine. CONCLUSION: The ability of L-arginine to reduce myogenic tone is independent of nitric oxide. This effect may be partially pH dependent but the osmolality of the solution appears to be a major factor. Hyperosmolar solutions might be worthy of further investigation as agents that affect anal tone.     

大鼠门静脉高压症及梗阻性黄疸时细菌移位与黄嘌呤脱氢酶和黄嘌呤氧化酶的关系

目的探讨大鼠门静脉高压症（porta; ju[ertemsopm,PH）及梗阻性黄疸（obstructive jaundioe,OJ）时,细菌移位（bacterial translocation,BT）与黄嘌呤氧化酶（xanthine oxidase,XO）、黄嘌呤脱氢酶（xanthine dehydrogenase,XD）之间的关系。方法将雄性SD大鼠60只随机分为对照组（A组）,胆总管结扎组（B组）和门静脉缩窄组（C组）,每组20只。术后第3周取肠系膜淋巴结、脾、肝组织及门静脉、腔静脉血细菌培养,测定门静脉压力（free portal pressure,FPP）,及肠XO,XD活性水平。结果B组及C组细菌移位率明显高于对照组（P〈0．01）,对照组为12％,B组和C组分别为28％和54％;B组和C组空肠XO水平活性明显高于对照组（P〈0．01）,B组和C组门静脉压力也较对照组升高。细菌移位率与XO活性成正相关（r=0．603）。XD活性水平无显著差异。结论门静脉高压症及梗阻性黄疸时可发生细菌移位,可能与肠黏膜屏障被破坏通透性增强有关,肠壁XO水平活性增强引起肠黏膜屏障通透性增高有助于细菌移位发生。     

Effect of granulocyte-macrophage colony stimulating factor on bacterial translocation after experimental obstructive jaundice.

OBJECTIVE: To investigate the effects of granulocyte-macrophage colony stimulating factor (GM-CSF) on bacterial translocation promoted by obstructive jaundice. DESIGN: Controlled animal study. SETTING: University hospital, Turkey. ANIMALS: 30 male Wistar albino rats. INTERVENTIONS: The first group (n = 10) was the sham operation (control) group, and the second and the third (n = 10 each) had common bile duct (CBD) ligation and division under sterile conditions. The third group were also treated with GM-CSF 200 ng subcutaneously daily between the fifth and ninth postoperative days. All animals were killed on the tenth day, and evaluated biochemically and histopathologically. Mesenteric lymph nodes were cultured under aerobic conditions. MAIN OUTCOME MEASURES: Biochemical analysis, histopathological evaluation, and aerobic cultures. RESULTS: There was no bacterial translocation in either the control or GM-CSF groups, whereas Escherichia coli and Salmonella typhimurium were found in 4 and 2 animals, respectively in the ligation group. Although no aerobic bacteria was found in controls and the GM-CSF groups, bacterial translocation was 6/10 in the ligation alone group (p <0.01). CONCLUSION: Activation of inflammatory response with GM-CSF is highly effective in prevention of bacterial translocation in obstructive jaundice.     

Increased nitric oxide production in hepatocytes is involved in liver dysfunction following obstructive jaundice

BACKGROUND: Obstructive jaundice damages critical functions in the liver. However, the mechanisms involved in hepatic dysfunction are obscure. Nitric oxide is implicated in liver injury under various pathological conditions. We previously reported that proinflammatory cytokine interleukin-1beta (IL-1beta) stimulated the production of nitric oxide in hepatocytes, which was associated with mitochondrial dysfunction. Studies were performed to examine whether obstructive jaundice influences the production of nitric oxide in hepatocytes and alters hepatic energy metabolism. MATERIAL AND METHODS: Hepatocytes were isolated and cultured from a rat model of obstructive jaundice or sham control. Nitric oxide production, ATP content, and ketone body ratio (acetoacetate/beta-hydroxybutyrate; KBR) were compared between the two groups in the presence of IL-1beta. RESULTS: Hepatocytes obtained from obstructive jaundice rats markedly increased the levels of nitric oxide production stimulated by IL-1beta compared with those from sham control. Western blot analysis revealed that the enhancement of nitric oxide production was a posttranslational event, since protein levels of inducible nitric oxide synthase (NOS) were unchanged between the two groups. IL-1beta decreased cellular ATP content in obstructive jaundice but not in sham control. Further, the KBR, which is a marker of mitochondrial redox state, was lower in obstructive jaundice than in sham control. Addition of N(G)-monomethyl-L-arginine, an inhibitor of NOS, abolished the decreases in ATP content and KBR as well as the nitric oxide production. CONCLUSIONS: These results indicate that a priming of nitric oxide production following obstructive jaundice is associated with the alteration of hepatic energy metabolism in part through mitochondrial dysfunction. Regulation of nitric oxide production may be a useful therapy for preventing liver dysfunction in obstructive jaundice.