Rat Model Of Obstructive Jaundice Research Articles

Mechanism of scar formation following Roux-en-Y choledochojejunostomy in a novel rat model of obstructive jaundice.

BackgroundThe present study aimed to analyze the scar formation mechanism following Roux-en-Y choledochojejunostomy (CJS) in a novel rat model of obstructive jaundice.MethodsThe biliary obstruction model of Sprague-Dawley (SD) rats was established in advance, and 24 rats were randomly divided into 4 groups (control group, 1-day ligation group, 3-day ligation group, and 5-day ligation group). Changes in postoperative weight, common bile duct diameter, and laboratory indexes were analyzed to determine the best operation time. Roux-en-Y CJS in rats was studied based on the model, and the rats were randomly divided into 4 groups [control group, 3-day choledochojejunostomy (CJS) group, 7-day CJS group, and 30-day CJS group]. The same indexes were analyzed, and the characteristics of scar formation were evaluated by histopathology and polymerase chain reaction examination.ResultsThe third day after common bile duct ligation is the best time for a Roux-en-Y CJS. The common bile duct diameter expands to 4.2 mm on average, and these physiological characteristics are consistent with current standard clinical findings. After completing CJS, the rats’ weight returned to normal levels, and alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bilirubin (TB), direct bilirubin (DB), and C-reactive protein (CRP) indexes gradually decreased (P<0.05). Anastomotic stoma diameter tended to narrow with time and was significantly narrower on day 30 than preoperation. After CJS, the expression of α-smooth muscle actin (α-SMA) peaked in the early stage and was still higher than that of the control group in the bile duct wall 1 month postoperatively (P<0.05). Transforming growth factor-β1 (TGF-β1) expression gradually increased and was higher than that of the control group at each stage postoperatively (P<0.05).ConclusionsThe rat Roux-en-Y CJS model is more in line with our surgical model, and the clinical condition has potential applicability for the study of CJS scar formation. Scar formation following CJS in rats is characterized by the activation of fibroblasts caused by early inflammatory stimulation, which leads to the proliferation of collagen and smooth muscle fibers, resulting in scars.

Agmatine alleviates hepatic and renal injury in a rat model of obstructive jaundice

BackgroundThe cholestatic liver disease could develop in association with a wide range of etiologies. The liver is the most affected organ by cholestasis. It has also been found that the kidney is severely injured during cholestasis. Oxidative stress seems to play a fundamental role in the pathogenesis of cholestasis-induced hepatic and renal injury. The current study was designed to evaluate the effects of agmatine supplementation on hepatic and renal injury and its potential mechanisms of action. MethodsRats underwent bile duct ligation (BDL) surgery. BDL animals were treated with agmatine (5, 10, and 20 mg/kg, gavage) for seven consecutive days. ResultsSignificant reactive oxygen species formation, lipid peroxidation, increased oxidized glutathione level, decreased tissue antioxidant capacity and depleted reduced glutathione (GSH) were detected in cholestatic animals. Moreover, mitochondrial indices, including ATP level, membrane potential, lipid peroxidation, and swelling, were deteriorated in both liver and kidney of cholestatic rats. Liver fibrosis and renal tissue histopathological changes were also evident in BDL rats. It was found that agmatine supplementation significantly alleviated cholestasis-induced hepatic and renal injury. ConclusionThe mechanism of action of agmatine could be related to its antioxidant properties and the positive effects of this amine on mitochondrial indices.

Effect of sildenafil citrate on the liver structure and function in obstructive jaundice: An experimental study.

We aimed to investigate the effect of 10 mg/kg sildenafil on the structure and function of the liver in a rat model of obstructive jaundice. Sixty-two male Wistar albino rats were distributed into six different groups. Obstructive jaundice was performed by legating the common bile duct. 10 mg/kg sildenafil citrate in drinking water was delivered orally after the operation before sacrificing them. Rats were sacrificed either after 10 or 28 days according to the study design. The blood and tissue samples from the liver were obtained to perform a biochemical and histopathological analysis to study functional and structural changes in the liver. At the 10th day, there was no difference between the sildenafil-treated and control groups with regard to the aspartate aminotransferase and alanine aminotransferase levels (p=0.423, p=0.661). The alkaline phosphatase total bilirubin levels among the groups were statistically different (p<0.001). At the 28th day, liver function tests except alanine aminotransferase showed significant differences among the groups (p<0.001). Liver function tests did not changed significantly between the 10th and 28th day in sildenafil-treated rats (p>0.05). Significant differences were observed among the groups with regard to cholestasis, fibrosis, inflammation, and necrosis (p<0.001). However, edema increased in the sildenafil-treated group (p<0.001). On the 28th day, the severity of structural changes in the liver after obstructive jaundice, except edema, reduced significantly (p<0.001). The sildenafil-treated groups at different time points didn't show any statistical difference in histopathological changes (p>0.05). Oral administration of 10 mg/kg sildenafil citrate dramatically reverses the biochemical and histopathological liver changes induced by obstructive jaundice in rats.

Effect of artenisiae scopariae and poriae powder on calpain-2 expression in liver tissue from rats with obstructive jaundice

To explore the eff ect of artenisiae scopariae and poriae powder (ASPD) on calpain-2 expression in liver tissue from rats with obstructive jaundice. The rat model of obstructive jaundice was established. SD rats was divided into the control group, the obstructive jaundice group, the obstructive jaundice model plus ASPD group, the obstructive jaundice model plus saline group. Th e serum levels of TBIL, ALT, AST and other biochemical indexes were detected. The pathological changes of liver tissue were evaluated by HE staining. The calpain-2 mRNA and protein expression in liver was measured by Real-time PCR and immunohistochemistry or Western blot, respectively. The calpain-2 mRNA and protein expression levels were significantly up-regulated in live tissues from the rats with obstructive jaundice in a time-dependent manner. The ASPD could inhibit the calpain-2 expression in rats with obstructive jaundice concomitant with the decreased liver damage and the improved liver function, suggesting that calpain-2 was involved in endoplasmic reticulum stress-mediated cellular apoptosis and the occurrence of obstructive jaundice. ASPD could be used for patients with obstructive jaundice to promote the recovery of liver function after operation and to reduce the incidence of complications, which provide a theoretical basis for the reasonable application of traditional Chinese medicine in the peroperative period.

Metabolomics changes in a rat model of obstructive jaundice: mapping to metabolism of amino acids, carbohydrates and lipids as well as oxidative stress.

The study examined the global metabolic and some biochemical changes in rats with cholestasis induced by bile duct ligation (BDL). Serum samples were collected in male Wistar rats with BDL (n = 8) and sham surgery (n = 8) at day 3 after surgery for metabolomics analysis using a combination of reversed phase chromatography and hydrophilic interaction chromatography (HILIC) and quadrupole-time-of-flight mass spectrometry (Q-TOF MS). The serum levels of malondialdehyde (MDA), total antioxidative capacity (T-AOC), glutathione (GSH) and glutathione disulfide (GSSG), the activities of superoxide dismutase (SOD) and glutathion peroxidase (GSH-Px) were measured to estimate the oxidative stress state. Key changes after BDL included increased levels of l-phenylalanine, l-glutamate, l-tyrosine, kynurenine, l-lactic acid, LysoPCc (14:0), glycine and succinic acid and decreased levels of l-valine, PCb (19:0/0:0), taurine, palmitic acid, l-isoleucine and citric acid metabolism products. And treatment with BDL significantly decreased the levels of GSH, T-AOC as well as SOD, GSH-Px activities, and upregulated MDA levels. The changes could be mapped to metabolism of amino acids and lipids, Krebs cycle and glycolysis, as well as increased oxidative stress and decreased antioxidant capability. Our study indicated that BDL induces major changes in the metabolism of all 3 major energy substances, as well as oxidative stress.

Protective effects of intravenous anesthetics on kidney tissue in obstructive jaundice

To evaluate the protective effects on kidney tissue of frequently used intravenous anesthetics (ketamine, propofol, thiopental, and fentanyl) in rats with obstructive jaundice. There is an increased incidence of postoperative acute renal failure in patients with obstructive jaundice. Thirty-two Wistar-albino rats were randomly divided into four equal groups. Laparatomy was performed on each animal in the four groups and common bile ducts were ligated and severed on day 0. After 7 d, laparotomy was again performed using ketamine, propofol, thiopental, or fentanyl anesthesia whose antioxidative properties are well known in oxidative stress in a rat liver model of obstructive jaundice. After 2 h, the rats were sacrificed. Renal tissue specimens were analyzed for catalase, superoxide dismutase and malondialdehyde enzymes activities. All values are expressed as the mean ± SD. P values less than 0.05 were considered statistically significant. All animals survived without complications until the end of the study. Enlargement in the bile duct and obstructive jaundice were observed in all rats. Catalase was found to be significantly lower in the fentanyl group than in the ketamine (P = 0.039), propofol (P = 0.012), and thiopental (P = 0.001) groups. Superoxide dismutase activities were similar in all groups (P > 0.05). Malondialdehyde was found to be significantly lower in the ketamine group than in the propofol (P = 0.028), thiopental (P = 0.002) and fentanyl (P = 0.005) groups. Malondialdehyde was also lower in the fentanyl group than in the thiopental group (P = 0.001). The results showed that obstructive jaundice sensitizes renal tissue to damage under the different anesthetics. Among the agents tested, ketamine and propofol generated the least amount of oxidative stres on renal tissues in this rat model of obstructive jaundice created by common bile duct ligation. The importance of free radical injury in renal tissue in obstructive jaundice under different intravenous anesthetics during hepatobiliary and liver transplant surgery should be considered for prevention of postoperative acute renal failure.

Human adrenomedullin and its binding protein ameliorate sepsis-induced organ injury and mortality in jaundiced rats

Sepsis is a serious complication for patients with obstructive jaundice. Although administration of adrenomedullin (AM) in combination with its binding protein (AMBP-1) is protective after injury, it remains unknown whether AM/AMBP-1 ameliorates sepsis-induced organ injury and mortality in the setting of biliary obstruction. The aim of this study is, therefore, to test the efficacy of human AM/AMBP-1 in a rat model of obstructive jaundice and polymicrobial sepsis. To study this, obstructive jaundice was induced in male adult rats (275–325 g) by common bile duct ligation (BDL). One week after BDL, the rats were subjected to sepsis by cecal ligation and puncture (CLP). Plasma levels of AM and AMBP-1 were measured at 20 h after CLP. In additional groups of BDL + CLP rats, human AM/AMBP-1 (24/80 μg/kg body weight (BW)) or vehicle (i.e., human albumin) was administered intravenously at 5 h after CLP. Blood and tissue samples were collected at 20 h after CLP for various measurements. To determine the long-term effect of human AM/AMBP-1 after BDL + CLP, the gangrenous cecum was removed at 20 h after CLP and 7-day survival was recorded. Our results showed that plasma levels of AM were significantly increased while AMBP-1 levels were markedly decreased after BDL + CLP ( n = 8, P < 0.05). Administration of human AM/AMBP-1 attenuated tissue injury and inflammatory responses after BDL + CLP. Moreover, human AM/AMBP-1 significantly increased the survival rate from 21% ( n = 14) to 53% ( n = 15). Thus, human AM/AMBP-1 ameliorates sepsis-induced organ injury and mortality in jaundiced rats. Human AM/AMBP-1 can be further developed as a novel treatment for sepsis in jaundiced patients.

Effects of carbon dioxide pneumoperitoneum on hepatic function in obstructive jaundice: an experimental study in a rat model

The physiology of the patient during laparoscopy differs from that of open surgery. Both pneumoperitoneum and obstructive jaundice impair the hepatic function, but the combined insult has not been previously examined. In this study, we aimed to investigate the effects of carbon dioxide (CO(2)) pneumoperitoneum on hepatic function in a rat model of obstructive jaundice. Forty-four male Sprague-Dawley rats were divided into four groups: group 1 (n = 10), sham-operated group; group 2 (n = 12), obstructive jaundice group; group 3 (n = 10), CO(2) pneumoperitoneum group; and group 4 (n = 12), obstructive jaundice and CO(2) pneumoperitoneum group. Common bile duct was ligated and divided in the obstructive jaundice groups. After 6 days, a 12-mmHg pneumoperitoneum was induced, maintained for 60 min, and released for 120 min. Blood samples were drawn for the measurement of white blood cell and platelet counts, serum liver enzymes (aspartate aminotransferase [AST], alanine aminotransferase [ALT], total bilirubin). Tissue samples were obtained for analyses of malondialdehyde (MDA), glutathione (GSH), and superoxide dismutase (SOD) levels. We evaluated the degree of liver injury on a grading scale from 0 to 4, histopathologically. Pneumoperitoneum after biliary obstruction resulted in an increase in AST and ALT levels and a decrease in white blood cell and platelet counts. However, changes in liver tissue MDA, GSH, and SOD levels did not correlate with the changes in AST and ALT levels and white blood cell and platelet counts. After sham operation with pneumoperitoneum, the GSH levels in liver homogenate were significantly decreased in the group 3 when compared to the group 2. On the other hand, obstructive jaundice itself caused significant reduction in the SOD activity of liver homogenate in comparison to the group 3. Histopathologically, sinusoidal congestion and vacuolization were more severe in the group 3. Alterations in hepatic function occur in pneumoperitoneum applied jaundiced subjects. However, there were no statistically significant differences between the groups 2 and 4 with regard to white blood cell and platelet counts, serum liver enzymes including AST, ALT, and total bilirubin values, MDA and GSH levels and SOD activity of liver homogenate, and histologic damage. These results indicate that there is no additional risk on liver function associated with pneumoperitoneum performed in obstructive jaundice.

Effects of sulfasalazine on lipid peroxidation and histologic liver damage in a rat model of obstructive jaundice and obstructive jaundice with lipopolysaccharide-induced sepsis

Background: Sulfasalazine, an inhibitor of cyclooxygenase, 5-lipoxygenase, and nuclear factor κB (NF-κB), has been found to alleviate oxidative damage, proinflammatory cytokine production, bile-duct proliferation, neutrophil infiltration, and fibrosis. Therefore, it may have a potential effect in attenuating lipid peroxidation and histologic liver damage in patients with biliary obstruction and biliary obstruction with sepsis. Objective: The aim of this study was to investigate the effect of sulfasalazine on lipid peroxidation and histologic liver damage due to obstructive jaundice (OJ) and to OJ with lipopolysaccharide (LPS)-induced sepsis in an experimental model. Methods: Male Wistar rats, weighing 150 to 220 g, were randomized into 6 groups: OJ; OJ + LPS; OJ + sulfasalazine; OJ + sulfasalazine + LPS (sulfasalazine administered before sepsis); OJ + LPS + sulfasalazine (sulfasalazine administered after sepsis); and sham. Liver malondialdehyde (MDA) and myeloperoxidase (MPO) activities were assessed to monitor lipid peroxidation and neutrophil infiltration in liver tissue. Histologic liver damage was evaluated with hematoxylin-eosin stained slides. Liver tissue NF-κB and caspase-3 expression were studied immunohistopathologically to evaluate lipid peroxidation, liver damage, and hepatocyte apoptosis. Results: Forty-eight rats were evenly randomized into 6 groups of 8. MDA ( P = 0.001), MPO ( P = 0.001), NF-κB ( P = 0.003), caspase-3 expression ( P = 0.002), and liver injury scores ( P = 0.002) increased significantly in the OJ group compared with the sham group. Compared with the OJ group, MDA ( P = 0.030) and MPO levels ( P = 0.001), and liver injury scores ( P = 0.033) were decreased significantly in the OJ + sulfasalazine group. In the OJ + sulfasalazine + LPS and OJ + LPS + sulfasalazine groups, MDA ( P = 0.008 and P = 0.023, respectively) and MPO (both, P = 0.001) were significantly decreased; however, liver NF-κB, caspase-3 expression, and liver injury scores were not significantly different compared with the OJ + LPS group. There was no significant difference between the OJ + LPS + sulfasalazine and OJ + sulfasalazine + LPS groups in regard to all end points when comparing the effects of sulfasalazine administered before or after sepsis. Conclusions: Sulfasalazine was associated with decreased neutrophil accumulation and lipid peroxidation in these rats with OJ. Administration of sulfasalazine before or after LPS-induced sepsis was associated with a reduction in lipid peroxidation and neutrophil accumulation; however, it did not attenuate histologic liver damage. There was no difference between the findings when sulfasalazine was administered before or after sepsis in OJ.

Phenylalanine Breath Test as a Method to Evaluate Hepatic Dysfunction in Obstructive Jaundice 1

The purpose of this study was to investigate whether the hepatic dysfunction associated with obstructive jaundice can be measured from changes in expiratory 13CO2 levels after intravenous administration of l-[1-(13)C]phenylalanine, using a rat model of obstructive jaundice. Under pentobarbital anesthesia, bile duct ligation (BDL) was performed (n=12). In the control group, simple laparotomy was performed (n=12). On postoperative day 7, 20 mg/kg l-[1-(13)C]phenylalanine was administered via the femoral vein. Phenylalanine breath test (PBT) was performed for 30 min. We compared single point of 13CO2 level (SPT: T: min) and sum of 13CO2 output (ST) values between BDL and control rats. We examined the correlation of SPT or ST with phenylalanine hydroxylase activity (PHA) and blood chemical parameters. Both SPT and ST values decreased in BDL compared to control 3 min after the start of PBT (SP10; 103+/-12 (per thousand) versus 84+/-16 (per thousand) P=0.025). PHA/g liver in BDL was significantly decreased compared to control (40.81+/-4.80 (U) versus 28.93+/-9.60 (U) P=0.008). PHA/g liver was correlated with SPT with correlation coefficient of more than 0.715, 10 min after the start of PBT, and the maximum correlation was at SP20 (r=0.801). Blood chemical parameters were correlated with S15 (total bilirubin, r=-0.717; alkaline phosphatase, r=-0.841; gamma-glutamyl transpeptidase, r=-0.759; alanine aminotransferase, r=-0.776; albumin, r=0.819). In the breath test with intravenously l-[1-(13)C]phenylalanine, hepatic dysfunction associated with obstructive jaundice could be measured in a short period.

Differences in Biliary Lipid Excretion after Major Hepatectomy in Obstructive Jaundiced Rats with Preoperative Internal, External, or No Biliary Drainage

Necessity of preoperative biliary drainage for patients with obstructive jaundice is still controversial. We recently reported that liver regeneration after major hepatectomy was better restored in a rat model of obstructive jaundice with preoperative internal biliary drainage than that without biliary drainage or with external biliary drainage. The aim of this study was to investigate the differences in biliary lipid excretion after hepatectomy in obstructive jaundiced rats with or without preoperative internal or external biliary drainage. After bile duct ligation for 7 days, rats were randomly divided into the three groups; obstructive jaundice-hepatectomy (OJ-Hx), internal biliary drainage-hepatectomy (ID-Hx), and external biliary drainage-hepatectomy (ED-Hx) groups. 70% hepatectomy and internal biliary drainage were carried out 7 days after biliary decompression in the latter two groups and without biliary decompression in the OJ-Hx group. On the day of and on days 1, 2, 3 and 7 after hepatectomy, the liver weight, DNA synthesis rate, biliary lipids excretion rates, and bile acid composition were determined. In the ID-Hx group, the DNA synthesis rate and relative liver weight were significantly higher than those of the OJ-Hx and ED-Hx groups. The excretion rates of biliary lipids were disturbed in the ED-Hx group compared with those in the ID-Hx group and the values in the OJ-Hx group were in-between the ID-Hx and ED-Hx group. The liver regeneration rate was significantly correlated with bile flow and excretion rates of biliary lipids. The maintenance of enterohepatic circulation of biliary lipids before hepatectomy may be important for the liver regeneration.

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-1β (IL-1β) 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/β-hydroxybutyrate; KBR) were compared between the two groups in the presence of IL-1β.Results. Hepatocytes obtained from obstructive jaundice rats markedly increased the levels of nitric oxide production stimulated by IL-1β 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-1β 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 NG-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.

Increased renal expression of bilirubin glucuronide transporters in a rat model of obstructive jaundice.

Regulation of bilirubin glucuronide transporters during hyperbilirubinemia in hepatic and extrahepatic tissues is not completely clear. In the present study, we evaluated the regulation of the bilirubin glucuronide transporters, multidrug resistance-associated proteins (MRP)2 and 3, in rats with obstructive jaundice. Bile duct ligation (BDL) or sham operation was performed in Wistar rats. Liver and kidneys were removed 1, 3, and 5 days after BDL (n = 4, in each group). Serum and urine were collected to measure bilirubin levels just before animal killing. MRP2 And MRP3 mRNA expressions were determined by real-time RT-PCR. Protein expression of MRP2 and MRP3 was determined by Western blotting. Renal MRP2 function was evaluated by para-aminohippurate (PAH) clearance. The effect of conjugated bilirubin, unconjugated bilirubin, human bile, and sulfate-conjugated bile acid on MRP2 gene expression was also evaluated in renal and hepatocyte cell lines. Serum bilirubin and urinary bilirubin excretion increased significantly after BDL. In the liver, the mRNA expression of MRP2 decreased 59, 86, and 82%, and its protein expression decreased 25, 74, and 93% compared with sham-operated animals after 24, 72, and 120 h of BDL, respectively. In contrast, the liver expression of MRP3 mRNA increased 138, 2,137, and 3,295%, and its protein expression increased 560, 634, and 612% compared with sham-operated animals after 24, 72, and 120 h of BDL, respectively. On the other hand, in the kidneys, the mRNA expression of MRP2 increased 162, 73, and 21%, and its protein expression increased 387, 558, and 472% compared with sham-operated animals after 24, 72, and 120 h of BDL, respectively. PAH clearance was significantly increased after BDL. The mRNA expression of MRP2 increased in renal proximal tubular epithelial cells after treatment with conjugated bilirubin, sulfate-conjugated bile acid or human bile. Upregulation of MRP2 in the kidneys and MRP3 in the liver may be a compensatory mechanism to improve bilirubin clearance during obstructive jaundice.

Bacterial translocation and intestinal morphological findings in jaundiced rats.

The susceptibility to sepsis in obstructive jaundice may be related to bacterial translocation (BT) from the gastrointestinal tract. We evaluated BT to visceral organs and morphological changes of the intestinal mucosa in a rat model of obstructive jaundice. Animals were randomly divided into two groups: in group A the common bile duct was tied and divided, while group B had the bile duct mobilized but not tied. After seven days, peritoneal swabs and liver, spleen, pancreas, lung, mesenteric lymph nodes (MLN), cecum, and terminal ileum biopsies were obtained for cultures. Light and electron microscopy were performed on intestinal samples. The TUNEL assay was performed to detect apoptosis. Data were analyzed using Fisher exact test and Student t test. Bile duct obliteration resulted in an increased incidence of BT. Seven days after duct obliteration, BT to the peritoneal cavity was evident in 37.5% of the animals in group A and 25% in group B. The respective BT rates for the two groups were: 42.8% vs 37.5% to MLN, 71.4% vs 25% to liver, 42.8% vs 12.5% to spleen, 28.6% vs 0% to pancreas and 14.3% vs 0% to lungs. Despite a trend, this was not statistically significant. Cecal counts did not differ statistically among the groups, while ileal counts were significantly higher in jaundiced rats (P < 0.05). Structural and ultrastructural abnormalities were evident only in the mucosa of the terminal ileum of jaundiced rats. Apoptosis was significantly increased in the terminal ileum of jaundiced rats (P < 0.002). This study suggests the possible association of biliary obstruction and BT. The nonspecific physical injury observed may contribute to breakdown of gastrointestinal barrier function thus promoting BT.

Biliary decompression reduces the susceptibility to ethanol-induced ulcer in jaundiced rats

We investigated the gastric response to an ulcerogenic irritant and the change in gastric functions in an experimental rat model of obstructive jaundice, with or without biliary drainage. After biliary obstruction for 14 days, rats with ligated bile duct (BDL) were randomly divided into three groups: BDL group without biliary drainage, BDL followed by choledochoduodenostomy (CD) or a choledochovesical fistula (CVF). The gastric functions were evaluated 2 weeks after the surgery. Gastric damage, induced by orogastric administration of ethanol, was evaluated 30 min later using a lesion index and microscopic scoring was then performed on fixed stomachs. Basal gastric acid secretion was measured by the pyloric ligation method.The lesion index and maximum lesion depth did not differ in the BDL and sham groups, while they were significantly reduced in the CD group. Gastric acid output and secretory volume were reduced in the BDL group compared to the sham group, while these reductions were abolished in the CD group. Afferent denervation with capsaicin further reduced the ulcer index in the later group. Our data suggest that gastric mucosal susceptibility to injury is dependent on the normal flow of bile into the duodenal lumen, which appears to be a requirement for adaptive gastric cytoprotection.

An Improved Rat Model of Obstructive Jaundice and Its Reversal by Internal and External Drainage

Background. A simple and reproducible rat model that allows studies of the reversal of obstructive jaundice (OJ) by internal (ID) and external (ED) drainage is not available at present.Methods. OJ was induced in rats by double ligation and division of the common bile duct. To minimize tissue handling and dissection the duodenum was extracted with a ophthalmic muscle hook and the common bile duct isolated using very fine forceps. One week after bile duct ligation, ID was accomplished by implanting a length of infant feeding tube between the dilated bile duct and the duodeum. ED was achieved by placing a PVC tube into the dilated bile duct and exteriorizing the other end at the nape of the neck.Results. Minimal adhesions were found around the dilated common bile duct, which made relaparotomy for drainage easy. Alanine transaminase, total bilirubin, alkaline phosphatase, and γ-glutamytransferase were significantly raised after bile duct ligation. All parameters returned to control levels after ID for 7 days. In the ED group plasma albumin was significantly decreased and alkaline phosphatase remained marginally elevated.Conclusions. We have developed a simple and reproducible rat model that allows for the study of reversal of OJ by ID or ED. We also demonstrated that ID is superior to ED in reversing impaired liver function in OJ.

Polyethylene glycol-modified bilirubin oxidase improves hepatic energy charge and urinary prostaglandin levels in rats with obstructive jaundice

Background/Aims: No study has so far been conducted to clarify whether the presence of hyperbilirubinemia is detrimental to liver and renal functions. In the present study, the effects of polyethylene glycol-modified bilirubin oxidase (PEG-BOX) therapy on liver and renal function tests, hepatic energy charge and urinary prostaglandin levels were evaluated in a rat model of obstructive jaundice. Methods: Sprague-Dawley rats were used in the experimental model of obstructive jaundice. PEG-BOX or an equivalent amount of PEG alone was intravenously injected into the animals and sampling of blood and urine, and liver harvesting were done sequentially after bile duct ligation. Results: Conventional liver function tests showed no difference between PEG-BOX and control groups. However, bilirubin concentrations in the peripheral blood and liver tissue specimens markedly decreased, and the hepatic energy charge significantly increased in the PEG-BOX group as compared to controls. The blood concentration of bile acid was lower, but its urinary excretion was higher in the PEG-BOX group than in the control group. In vitro incubation of PEG-BOX with serum from rats with obstructive jaundice decreased the concentration of bilirubin but not that of bile acid. The urinary levels of prostaglandin E2 and the thromboxane B2/6-keto-prostaglandin F1 a ratio were significantly lower in the PEG-BOX group than in the control group. Conclusions: The systemic reduction of bilirubin concentration may contribute to normalization of the urinary levels of prostaglandins and thromboxane B2, to decrease in serum bile acid levels, and to improvement of the hepatic energy charge in obstructive jaundice. These findings suggest that preoperative improvement of jaundice may be beneficial to patients with obstructive jaundice.

Endotoxemia and Intestinal Mucosal Dysfunction after the Relief of Obstructive Jaundice by Internal and External Drainage in Rats

We studied the effects of external and internal biliary drainage on the development of endotoxemia in a rat model of obstructive jaundice. Male Donryu rats were allocated to four groups: sham operation, common hepatic bile duct ligation (BDL), internal or external biliary drainage after BDL, and biliary drainage after BDL with oral endotoxin administration. Portal and systemic blood endotoxin concentrations were measured and the histomorphology of the intestinal mucosa was examined. Portal endotoxemia was observed 7 days after BDL and both portal and systemic endotoxemia were observed after 14 days. Portal endotoxemia was reversed by both internal and external biliary drainage and systemic endotoxemia was prevented. The ratio of villous height to crypt depth in the mucosa of the terminal ileum was decreased in rats with external drainage. Oral administration of endotoxin induced marked disruption of the mucosal epithelium in rats with external biliary drainage, but not in rats with internal biliary drainage. Significant increases in portal and systemic blood endotoxin concentrations were observed only in the external drainage group after oral endotoxin administration. The relief of biliary obstruction effectively relieved portal endotoxemia. External biliary drainage, however, has the potentially deleterious effect of disrupting the intestinal mucosa, which may promote the development of endotoxemia. These findings have implications for the use of biliary drainage procedures to reduce postoperative complications in jaundiced patients.

ラット閉塞性黄疸減黄モデルの作製

ラット閉塞性黄疸減黄モデルの作製

Role of platelet-activating factor in hepatic responses after bile duct ligation in rats.

Role of platelet-activating factor (PAF) as a potential mediator of hepatic pathophysiology was investigated using a rat model of obstructive jaundice. Over a 1-wk course of bile duct ligation, a sixfold increase in tissue levels of PAF (1.57 +/- 0.43 ng/g vs. control 0.24 +/- 0.08 ng/g) occurred in the liver, whereas no change was observed in PAF levels in plasma. Concomitantly, endotoxin was detected in portal blood drawn from jaundiced rats, and antagonism of the putative effect of endotoxin by neomycin plus polymyxin B reduced local PAF concentrations in livers from jaundiced animals. Induction of neutropenia failed to alter the elevated hepatic PAF concentrations. Moreover, a large quantity of PAF was released spontaneously from Kupffer cells isolated from livers derived from jaundiced rats but not from endothelial cells or hepatocytes from the same animals. An in vitro study using cultured Kupffer cells from normal rats indicated that Kupffer cells secreted a significant amount of PAF in response to lipopolysaccharide challenge; pretreatment of cells with polymyxin B prevented this stimulated PAF release. Treatment of animals with either of two PAF receptor antagonists (BN 52021 and WEB 2170) partially prevented the increase in tissue levels of eicosanoids and O2-derived free radicals and partially alleviated liver injury as judged by the appearance of glutamate-pyruvate transaminase in the plasma of jaundiced rats. The present study indicates 1) that endogenous PAF may be an important signaling mediator for the hepatic inflammatory alterations associated with short-term bile duct ligation and 2) that the interaction of Kupffer cells with portal endotoxin is the mechanism by which PAF is produced locally.