Development of hepatorenal syndrome in bile duct ligated rats

AIM： To evaluate in bile duct ligated rats whether there were progressive alterations of renal function without changes in histopathology.
METHODS： Male Wistar rats were submitted to sham-surgery or bile duct ligation （BDL） and divided according to the post-procedure time （2, 4 and 6-wk）. To determine renal function parameters, rats were placed in metabolic cages and, at the end of the experiment, blood and urine samples were obtained. Histology and hydroxyproline content were analyzed in liver and renal tissue. RESULTS： Rats with 2 wk of BDL increased free water clearance （P = 0.02）, reduced urinary osmolality （P = 0.03） and serum creatinine （P = 0.01） in comparison to the sham group. In contrast, rats at 6 wk of BDL showed features of HRS, including significant increase in serum creatinine and reductions in creatinine clearance, water excretion and urinary sodium concentration. Rats with 4 wk of BDL exhibited an intermediate stage of renal dysfunction. Progressive hepatic fibrosis according to post-procedure time was confirmed by histology. The increased levels of liver hydroxyproline contrasted with the absence of structural changes in the kidney, as assessed by histology and unchanged hydroxyproline content in renal tissue.
CONCLUSION： Our data show that BDL produced progressive renal dysfunction without structural changes in the kidney, characterizing HRS. The present model will be useful to understand the pathophysiology of HRS.     

Opioid receptor antagonist promotes angiogenesis in bile duct ligated rats

Background and Aim:  Angiogenesis, formation of new capillaries from existing vasculature, plays a pivotal role in different pathological states such as many chronic inflammatory diseases including the chronic liver diseases. There is increasing evidence demonstrating accumulation of endogenous opioids and their role in the pathophysiology and manifestations of cholestasis, the main feature of a number of chronic progressive liver diseases. Hence, we investigated the significance of endogenous opioids in angiogenesis in an experimental model of cholestasis.
Methods:  Cholestasis was induced in male Sprague–Dawley rats by bile duct ligation and resection. Naltrexone, an opioid antagonist (20 mg/kg/day) was administered to cholestatic animals for 22 ± 1 days. The serial sections from liver tissue were stained with von Willebrand Factor antibody and micro-vessel density was assessed by calculating mean micro-vessel number in three hot spots high power microscopic fields.
Results:  Naltrexone treatment in bile duct ligated rats led to a marked increase in the micro-vessel number (6.34 ± 0.21 vs 5.61 ± 0.22) ( P  < 0.05), which had already increased during cholestasis.
Conclusion:  In order to clarify the impacts of opioid system blockade in cirrhosis, our findings demonstrate the promoting role of opioid antagonist in angiogenesis in a rat model of cholestasis.     

Estrogens maintain bile duct mass and reduce apoptosis after biliodigestive anastomosis in bile duct ligated rats

BACKGROUND/AIMS: Disapperacence of bile ducts (ductopenia) represents the terminal, common stage of human cholangiopathies, and estrogens exert a major role in stimulating cholangiocyte proliferation. We thus evaluated whether estrogen administration protect from the bile duct loss induced by the biliary-digestive diversion in bile duct ligated (BDL) rats. METHODS: After 3 weeks of BDL, rats were subjected to biliary-digestive diversion and treated with daily injections of 17beta-estradiol or a control solution. RESULTS: Both after 7 and 14 days from the biliary-digestive diversion a marked increase of the number of apoptotic cholangiocytes was observed. In contrast, 17beta-estradiol significantly reduced cholangiocyte apoptosis. 17beta-estradiol also prevented the biliary-digestive diversion-induced loss of PCNA-positive cholangiocytes and of the bile duct mass. Biliary-digestive diversion determined a marked reduction of ERK1/2 phopsphorylation in cholangiocytes that was reversed by the administration of 17beta-estradiol. CONCLUSIONS: This study indicates that estrogens prevent the increase of cholangiocyte apoptosis and loss of cholangiocyte proliferation induced by the biliary-digestive diversion in the BDL rat. In parallel, 17beta-estradiol also enhanced ERK1/2 phosphorylation, which is instead strongly reduced by the biliary-digestive diversion. These novel findings suggest that estrogens could prevent the evolution of cholangiopathies toward ductopenia.     

Taurohyodeoxycholate- and tauroursodeoxycholate-induced hypercholeresis is augmented in bile duct ligated rats

BACKGROUND/AIMS: Taurohyodeoxycholate (THDCA) and tauroursodeoxycholate (TUDCA) induce more bile flow per molecule excreted compared to endogenous bile acids. The aim of this study is to determine if the hypercholeretic effect of tauroursodeoxycholate or taurohyodeoxycholate in normal and bile duct ligated (BDL) rats is due to increased ductal secretion. METHODS: Normal or BDL rats were infused with tauroursodeoxycholate or taurohyodeoxycholate and bile flow, bicarbonate, bile salt, cholesterol, and phospholipid secretion were measured. Cholangiocytes were stimulated with taurohyodeoxycholate or tauroursodeoxycholate, and secretin-stimulated secretion was measured. RESULTS: Taurohyodeoxycholate and tauroursodeoxycholate increased bile flow more in BDL than normal rats. Tauroursodeoxycholate increased bicarbonate secretion more in BDL compared to normal rats. Taurohyodeoxycholate when infused with taurocholate increased bile flow (but not phospholipid excretion) to a greater degree in BDL compared to normal rats. Taurohyodeoxycholate and tauroursodeoxycholate decreased secretin-stimulated cholangiocyte secretion. CONCLUSIONS: Consistent with a ductal origin for bile acid-induced hypercholeresis, taurohyodeoxycholate and tauroursodeoxycholate produced a greater hypercholeresis in BDL than normal rats. Tauroursodeoxycholate- (but not taurohyodeoxycholate-) stimulated hypercholeresis is associated with increased HCO(3)(-) secretion. Tauroursodeoxycholate increases biliary HCO(3)(-) secretion by a mechanism unrelated to secretin-stimulated cholangiocyte secretion. Taurohyodeoxycholate-induced hypercholeresis in BDL rats is unrelated to enhanced phospholipid excretion.     

Endotoxemia produces coma and brain swelling in bile duct ligated rats

This study explores the hypothesis that the inflammatory response induced by administration of lipopolysaccharide (LPS) exacerbates brain edema in cirrhotic rats; and if so whether this is associated with altered brain metabolism of ammonia or anatomical disturbance of the blood-brain barrier. Adult Sprague-Dawley rats 4 weeks after bile duct ligation (BDL)/Sham-operation, or na?ve rats fed a hyperammonemic diet (HD), were injected with LPS (0.5 mg/kg, intraperitoneally) or saline, and killed 3 hours later. LPS administration increased brain water in HD, BDL, and sham-operated groups significantly (P < 0.05), but this was associated with progression to pre-coma stages only in BDL rats. LPS induced cytotoxic brain swelling and maintained anatomical integrity of the blood-brain barrier. Plasma/brain ammonia levels were higher in HD and BDL rats than in sham-operated controls and did not change with LPS administration. Brain glutamine/myoinositol ratio was increased in the HD group but reduced in the BDL animals. There was a background pro-inflammatory cytokine response in the brains of cirrhotic rats, and plasma/brain tumor necrosis factor alpha (TNF-alpha) and IL-6 significantly increased in LPS-treated animals. Plasma nitrite/nitrate levels increased significantly in LPS groups compared with non-LPS controls; however, frontal cortex nitrotyrosine levels only increased in the BDL + LPS rats (P < 0.005 versus BDL controls). CONCLUSION: Injection of LPS into cirrhotic rats induces pre-coma and exacerbates cytotoxic edema because of the synergistic effect of hyperammonemia and the induced inflammatory response. Although the exact mechanism of how hyperammonemia and LPS facilitate cytotoxic edema and pre-coma in cirrhosis is not clear, our data support an important role for the nitrosation of brain proteins.     

Effect of ursodeoxycholic acid administration on bile duct proliferation and cholestasis in bile duct ligated rat

The origin, mechanism, and significance of the bile duct proliferation (BDP) associated with cholestasis remain unexplained. This study examined the effect of oral administration of ursodeoxycholic acid (UDCA) on both BDP and cholestasis in the rat. After bile duct ligation, male Sprague-Dawley rats were treated for 30 days with either UDCA (5 mg/day) (group A) or saline solution (group B). Animals were sacrificed at day 30. The serum activity of aminotransferase (ALT, AST), alkaline phosphatase, and -glutamyltransferase (GGT) was significantly lower (P<0.01) in the UDCA-treated rats. Total serum bilirubin and total serum bile acids were lower (P<0.001) in group A. Moreover, the control of BA in bile was reduced also (P<0.02). Conversely, serum cholesterol levels were not different between the two groups. Histological examination showed that the number of ductular cells in the portal areas was significantly (P<0.001) reduced in UDCA-treated as compared to saline-treated rats. The replication activity, assessed as the number of bromodeoxyuridine-positive cells, was also significantly lower in treated animals (33±11 vs 64±22 per 1000 cells;P<0.001). Lobular bile ductules were three times larger in group B, and extrahepatic duct measurements confirmed this increase in size of the larger biliary ducts (P<0.001). These findings demonstrate that UDCA reduces BDP in response to BD ligation. Although the mechanism(s) of this effect is still hypothetical, UDCA may reduce the level of irritating bile salts such as chenodeoxycholic acid and lithocolate and increase periductular bile acid recirculation. These data support the beneficial effect of UDCA treatment in chronic cholestatic disease.     

Systemic hypotension and pressor responsiveness in cholestasis. A study in conscious 3-day bile duct ligated rats

It has been postulated that the physiological basis for systemic hypotension in cholestatic liver disease is the attenuated responsiveness of the cardiovascular system to sympathetic stimulation. Using conscious 3-day bile duct ligated rats, we tested this hypothesis by measuring the vasopressor and vasodilator responses following intravenous infusions of norepinephrine, tyramine, angiotensin II, angiotensin I and isoproterenol, in conjunction with the pressor responses to a head-up vertical tilt and a controlled hemorrhage. The results were compared to those obtained in conscious sham-operated rats. Bile duct ligation reduced the mean arterial blood pressure without a significant increase in heart rate. The pressor responses to the aforementioned drugs obtained in the bile-duct ligated rats were significantly attenuated from those the sham-operated rats. In contrast, bile duct ligation had no effect on the pressor responses to tilting and hemorrhage when compared to the responses obtained in the sham-operated rats. Despite the presence of systemic hypotension and attenuation of pressor response to vasoactive drugs, the ability of the cardiovascular system to respond to physiological stimuli appears to be intact in this model. Therefore, we conclude that blunted pressor responsiveness of the cardiovascular system is probably not an important physiological determinant of systemic hypotension in cholestatic liver disease.     

The effects of sodium deoxycholate, lactulose and glutamine on bacterial translocation in common bile duct ligated rats

BACKGROUND/AIMS: Sepsis is a major cause of post-operative morbidity and mortality in obstructive jaundice as a result of bacterial translocation from the gut. This study was conducted to investigate the effects of glutamine, lactulose, and the bile salt Na deoxycholate in preventing bacterial translocation in an animal model where obstructive jaundice was developed by common bile duct ligation. METHODOLOGY: Fifty Wistar albino rats were divided into 5 groups of 10 animals each. The animals in groups I-IV underwent common bile duct ligation and received, respectively, either saline, Na deoxycholate, lactulose or glutamine, orally. Group V had sham ligation and received saline orally. The animals were sacrificed at the end of the 7th day, and serum concentrations of bilirubin, aspartate aminotransferase (ALT), alanine aminotransferase (ALT), and alkaline phosphatase (AP) were measured. In addition, mesenteric lymph nodes were removed and cultured together with cecal content. Histopathologic examination of terminal ileum specimens was made. RESULTS: Na deoxycholate, lactulose and glutamine all reduced bacterial translocation rates to mesenteric lymph nodes (p<0.05), with glutamine causing the greatest effect. Na deoxycholate and lactulose prevented bacterial translocation by causing a decrease in cecal intraluminal bacterial content (p<0.001), while glutamine exerted its effect by preserving intestinal mucosal integrity. CONCLUSIONS: The integrity of the intestinal mucosal barrier is of paramount importance in preventing bacterial translocation, and the measures taken to protect mucosal integrity reduce bacterial translocation to a greater extent than those taken to decrease the number of bacteria in the gut.     

Bile acids content in brain of common duct ligated rats

Introduction. Cholestasis leads to liver cell death, fibrosis, cirrhosis, and eventually liver failure. Bile duct ligated rats constitute an interesting model to study the mechanism of cholestasis, and its action on several organs and tissues, including the brain.Aim. To analyze brain bile acids individually in ligated rats to evaluate if its profile is altered towards a more toxic condition in cholestasis.Material and methods. Male Wistar rats were used and separated in two groups: bile duct ligated rats and sham operated rats (n = 5 in each group). Bile acid profile was assessed in brain homogenates. Alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase determinations, bilirubin and ammonia plasma concentration were also measured in both groups.Results. Although the total amount of bile acids in control animal brains showed a higher concentration than in bile duct ligated rats, the bile acid profile in this group was found more toxic composition than in controls. Lithocholic acid was present in brain in higher concentration (87.4 % of total brain bile acids) in ligated rats and absent in controls. Alkaline phosphatase, bilirubin and ammonia were significantly higher in bile duct ligated rats than in control group.Conclusion. It was found a toxic brain bile acid profile during hepatic cholestasis which could be one of the explanations of hepatic encephalopathy observed in cholestatic diseases.     

Transcatheter cooling of intrahepatic bile duct during microwave coagulation therapy: A procedure to prevent bile duct injury

Microwave coagulation therapy (MCT) is a widely used and effective minimal invasive therapy for liver tumor. Bile duct injury, however, is a major obstacle to complete tumor necrosis. To facilitate the use of MCT for a liver tumor adjacent to the major bile duct, we developed a method for transcatheter cooling of the major intrahepatic bile duct. The procedure for this technique is: (1) an angular catheter is inserted into the designated bile duct via the cystic duct after cholecystectomy, and a small longitudinal cut is made in the common bile duct for drainage of the cooling liquid; (2) cool saline is continuously infused into the bile duct via the inserted catheter during MCT; (3) after the MCT, the small opening in the common bile duct is simply closed with two or three sutures, and a C-tube is inserted to prevent stenosis of the common hepatic duct. MCT with this newly developed surgical technique enabled complete tumor necrosis and bile duct preservation, and the technique is strongly recommended for treatment of liver tumor adjacent to the major bile duct.     

胆总管结扎诱导大鼠肝肺综合征模型的建立初步研究

目的 探讨胆总管结扎术诱导大鼠肝肺综合征(HPS)模型的建立.方法 40只SD大鼠被随机分为实验组30只和对照组(假手术组)10只,采用胆总管结扎术建立肝硬化和HPS模型.使用血气分析仪测定PaO2、PaCO2和pH.结果 在术后1 w,腹部超声检查显示实验组肝脏回声增粗,胆总管轻度扩张.在术后2 w,肝脏被膜不平整,...     

Allopurinol and glutamine attenuate bacterial translocation in chronic portal hypertensive and common bile duct ligated growing rats.

BACKGROUND: Spontaneous bacterial infections and septicaemia result in morbidity and mortality in patients with portal hypertension and obstructive jaundice. AIM: The aim of this study in rats was to investigate the incidence of bacterial translocation in portal hypertension and obstructive jaundice, and to evaluate the effects of allopurinol and glutamine. METHODS: Rats were subjected to sham laparotomy (SL), portal hypertension (PH) by calibrated stenosis of the portal vein, and common bile duct ligation (CBDL). Animals of each group were either treated with allopurinol (50 mg/kg twice a week), glutamine (1 g/kg/d), and allopurinol and glutamine. RESULTS: After four weeks, significant bacterial translocation in the untreated PH and CBDL rats occurred. Intestinal mucosal malondialdehyde concentrations (MDA), as an indicator for lipid peroxidation, and myeloperoxidase activity (MPO) released from activated neutrophils were also significantly increased (p < 0.01). Allopurinol and glutamine in PH and CBDL rats improved bacterial translocation, and decreased MDA and MPO values (p < 0.01). CONCLUSION: In PH and CBDL rats significant bacterial translocation, ileal mucosal lipid peroxidation, and neutrophil derived MPO activity occurred. Allopurinol and glutamine significantly reduced bacterial translocation, as well as ileal mucosal MDA and MPO activities.     

Hemodynamic and antifibrotic effects of a selective liver nitric oxide donor V-PYRRO/NO in bile duct ligated rats

INTRODUCTION Chronic liver diseases generally progress slowly from inflammation to fibrosis and in many cases to portal hypertension (PHT) and cirrhosis. PHT is responsible for the development of collateral venous circulation and esophageal varices which …     

The bile duct ligated rat: A relevant model to study muscle mass loss in cirrhosis

Metabolic Brain Disease - Muscle mass loss and hepatic encephalopathy (complex neuropsychiatric disorder) are serious complications of chronic liver disease (cirrhosis) which impact negatively on...