Reduction in phosphoenolpyruvate carboxykinase in rat liver parenchymal cells following experimentally induced cholestasis

The effect of experimentally induced cholestasis on the amount of phosphoenolpyruvate carboxykinase (PEPCK) was studied immunohistochemically in rat liver parenchyma. In control liver, the enzyme was mainly localized periportally and, although the enzyme content was much reduced, this distribution pattern was maintained up to 2 weeks after ligation of the common bile duct. At 4 and 8 weeks after ligation the enzyme content in parenchymal cells remained low, but became distributed homogeneously throughout the liver parenchyma. This suggests that after bile duct ligation, gluconeogenesis from lactate is impaired. This may well be the cause of the adaptive changes to enhance the glycogenolytic capacity of parenchymal cells to maintain as far as possible a constant blood glucose level.     

The involvement of altered vesicle transport in redistribution of Ca2+, Mg2+-ATPase in cholestatic rat liver

Vectorial sorting of plasma membrane protein-containing vesicles is essential for the establishment and maintenance of cell polarity. In the present study, the involvement of altered vesicle transport in the redistribution of membrane-bound Ca2+, Mg2+-ATPase resulting from cholestasis was investigated in hepatocytes. Cholestasis was induced in rat liver by common bile duct ligation. Ca2+, Mg2+-ATPase activity was demonstrated histochemically at the light and electron microscopical levels. Microtubules, an important factor for transcellular transport of vesicles, were studied in situ by immunofluorescence microscopy and electron microscopy in detergent-extracted preparations. The results showed that microtubules underwent significant changes after common bile duct ligation. The most pronounced alteration was focal accumulation of -tubulin in the cytoplasm of hepato cytes after 7 days of common bile duct ligation. At the electron microscopical level, the number of microtubules was increased considerably. In control livers, the activity of Ca2+, Mg2+-ATPase was localized only at the apical plasma membrane of hepatocytes, but it was also present at the basolateral plasma membrane after common bile duct ligation. The number of intracellular vesicles containing Ca2+, Mg2+-ATPase activity was increased strikingly, and some of them were associated with lateral membrane domains in which Ca2+, Mg2+-ATPase activity was found. It is concluded that common bile duct ligation induces the rearrangement of microtubules, which may disturb vectorial transport of Ca2+, Mg2+-ATPase-containing vesicles in hepatocytes, leading to the redistribution of Ca2+, Mg2+-ATPase. © 1998 Chapman & Hall     

Changes in the acinar distribution of some enzymes involved in carbohydrate metabolism in rat liver parenchyma after experimentally induced cholestasis

Extrahepatic cholestasis induced by ligation and transsection of the common bile duct caused a change in the parenchyma/stroma relationship in rat liver. Two weeks after ligation, the periportal zones of the parenchyma were progressively invaded by expanding bile ductules with surrounding connective tissue diverging from the portal areas. Parenchymal disarray developed and small clumps of hepatocytes or isolated hepatocytes were scattered within the expanded portal areas. These cells showed normal activity of lactate, succinate and glutamate dehydrogenase and may, therefore, be considered to be functionally active. After cholestasis the remainder of the liver parenchyma showed adaptational changes with respect to glucose homeostasis, as demonstrated by histochemical means. Glycogen stores disappeared completely whereas glycogen phosphorylase activity increased about ten fold. The increased glycogen phosphorylase activity and glycogen depletion indicate a greater glycogenolytic capacity in liver parenchyma after bile duct ligation to maintain as far as possible a normal plasma glucose concentration. The parenchymal distribution pattern of glucose-6-phosphatase activity did not change significantly after bile duct ligation. The isolated hepatocytes within the expanded portal tracts showed a high activity of this enzyme whereas the pericentral parenchyma was only moderately active. The distribution patterns of glucose-6-phosphate dehydrogenase and lactate dehydrogenase activity in the liver parenchyma were also largely unchanged after bile duct ligation, but the histochemical reaction for glucose-6-phosphate dehydrogenase activity demonstrated infiltration of the remainder of the parenchyma by non-parenchymal cells, possibly Küpffer cells and leucocytes as part of an inflammatory reaction. Under normal conditions the mitochondrial enzymes succinate and glutamate dehydrogenase show an opposite heterogenous distribution pattern in liver parenchyma. Following cholestasis both enzymes became uniformly distributed. The underlying regulatory mechanism for these different changes in distribution patterns of enzyme activities is not yet understood.     

The common bile duct ligation in rat: a relevant in vivo model to study the role of mechanical stress on cell and matrix behaviour

Common bile duct ligation leads to bile accumulation and liver fibrosis. In this model, little attention has been dedicated to the modification of the common bile duct. We have studied by histochemistry and immunohistochemistry, 3 and 5 days after ligation, the connective tissue modifications of the common bile duct wall. After bile duct ligation, compared with normal bile duct, a strong increase of the bile duct diameter, due to bile stasis, and a thickness of the bile duct wall were observed; numerous myofibroblasts expressing α-smooth muscle actin appeared in parallel with the detection of many proliferating connective tissue cells. These myofibroblasts secreted very early high amount of elastic fibre components, elastin and fibrillin-1. Elastic fibre increase was also observed close to the epithelial cell layer. Procollagen type III deposition was also induced 3 days after ligation but decreased thereafter, underlining that myofibroblasts modify their synthesis of extracellular matrix components to comply with the request. We show here that common bile duct ligation represents an invaluable model to study myofibroblastic differentiation and extracellular matrix adaptation produced by an acute mechanical stress.     

TNF-alpha and leptin in experimental liver fibrosis models induced by carbon tetrachloride and by common bile duct ligation

In this study we investigated TNF-alpha and leptin levels in two different liver fibrosis models induced by carbon tetrachloride (CCl(4)) and common bile duct ligation (CBDL). A total of 36 male rats of Albino-Wistar strain were allocated to three groups. One of the groups was the control. The second group received 0.15 ml 100 g(-1) CCl(4) subcutaneously for 6 weeks, 3 days per week. The third group underwent common bile duct ligation (CBDL) and was monitored for 4 weeks. Histopathological investigation included fibrosis, steatosis and inflammation. Serum IL-6 and TNF-alpha levels were analysed by ELISA methods and leptin was analysed by RIA. Fibrosis and steatosis increased significantly in the CCl(4) group in comparison with the CBDL group (p < 0.01; p < 0.001). Leptin and TNF-alpha levels in CCl(4) group were higher than those in the CBDL and control groups (p < 0.05). TNF-alpha and leptin levels were not related to each another in either the CCl(4) group or the CBDL group (r=0.22, p > 0.05; r=0.19, p > 0.05). The IL-6 level was higher in the CCl(4) group in relation to severity of inflammation (p < 0.05). TNF-alpha and leptin levels were higher in animals with liver fibrosis induced by CCl(4), than they were in those whose liver fibrosis was induced by common bile duct ligation. Leptin and TNF-alpha may be less effective on the development of liver fibrosis in the group which underwent common bile duct ligation.     

Interleukin-6 (IL-6) and acute-phase proteins in rats with biliary sepsis.

We measured serum interleukin-6 (IL-6) and acute-phase proteins, alpha 1-acid glycoprotein (AGP) and alpha 2-macroglobulin (alpha 2M), after a retrograde intrabiliary bacterial infection in rats with biliary obstruction. Maximum serum IL-6 was obtained at 6 h in rats following inoculation of bacteria (10(6) CFU/ml E. Coli) in the bile duct and it was higher than that observed in rats undergoing a bile duct ligation or a laparotomy. There was a strict relationship between the level of IL-6 at 6 h and the modified levels of AGP and alpha 2M at 48 h. AGP and alpha 2M levels were the highest in sera of rats with bile duct infection as compared with those found in sera of rats with bile duct ligation or laparotomy. After inoculation of E. Coli or E. Fecalis, blood IL-6 level was always higher at 6 h in inferior vena cava as compared with that found in the supra hepatic vein. These results indicate that IL-6 is synthesized after a biliary sepsis and that its blood level is higher in the systemic circulation than in the local circulation.     

Impairment of the organization of locomotor and exploratory behaviors in bile duct-ligated rats

Hepatic encephalopathy (HE) arises from acute or chronic liver diseases and leads to several problems, including motor impairment. Animal models of chronic liver disease have extensively investigated the mechanisms of this disease. Impairment of locomotor activity has been described in different rat models. However, these studies are controversial and the majority has primarily analyzed activity parameters. Therefore, the aim of the present study was to evaluate locomotor and exploratory behavior in bile duct-ligated (BDL) rats to explore the spatial and temporal structure of behavior. Adult female Wistar rats underwent common bile duct ligation (BDL rats) or the manipulation of common bile duct without ligation (control rats). Six weeks after surgery, control and BDL rats underwent open-field, plus-maze and foot-fault behavioral tasks. The BDL rats developed chronic liver failure and exhibited a decrease in total distance traveled, increased total immobility time, smaller number of rearings, longer periods in the home base area and decreased percentage of time in the center zone of the arena, when compared to the control rats. Moreover, the performance of the BDL rats was not different from the control rats for the elevated plus-maze and foot-fault tasks. Therefore, the BDL rats demonstrated disturbed spontaneous locomotor and exploratory activities as a consequence of altered spatio-temporal organization of behavior.     

Renal elimination of p-aminohippurate (PAH) in response to three days of biliary obstruction in the rat. The role of OAT1 and OAT3

Pharmacokinetic studies of the drugs administered to subjects with mechanical cholestasis are scarce. The purpose of the present study was to examine the effects of bile duct ligation of 3 days (peak of elevation of serum bile acids and bilirubin) on the systemic and renal PAH clearance and on the expression of cortical renal OAT1 and OAT3 in a rat model. PAH is the prototypical substrate of the renal organic anion transport system. Male Wistar rats underwent a bile duct ligation (BDL rats). Pair-fed sham-operated rats served as controls. BDL rats displayed a significantly lower systemic PAH clearance. Renal studies revealed a reduction in the renal clearance and in the excreted and secreted load of PAH in BDL rats. The OAT1 protein expression in kidney homogenates was not modified, but it decreased in the basolateral membranes from BDL rats. In contrast, OAT3 abundance in both kidney cortex homogenates and in basolateral membranes increased by 3 days after the ligation. Immunocytochemical studies (light microscopic and confocal immunofluorescence microscopic analyses) confirmed the changes in the renal expression of these transport proteins. The present study demonstrates the key role of OAT1 expression in the impaired elimination of PAH after 3 days of obstructive cholestasis.     

Polyphenols from Camellia sinenesis attenuate experimental cholestasis-induced liver fibrosis in rats

Accumulation of hydrophobic bile acids during cholestasis leads to generation of oxygen free radicals in the liver. Accordingly, this study investigated whether polyphenols from green tea Camellia sinenesis, which are potent free radical scavengers, decrease hepatic injury caused by experimental cholestasis. Rats were fed a standard chow or a diet containing 0.1% polyphenolic extracts from C. sinenesis starting 3 days before bile duct ligation. After bile duct ligation, serum alanine transaminase increased to 760 U/l after 1 day in rats fed a control diet. Focal necrosis and bile duct proliferation were also observed after 1-2 days, and fibrosis developed 2-3 wk after bile duct ligation. Additionally, procollagen-alpha1(I) mRNA increased 30-fold 3 wk after bile duct ligation, accompanied by increased expression of alpha-smooth muscle actin and transforming growth factor-beta and the accumulation of 4-hydroxynenonal, an end product of lipid peroxidation. Polyphenol feeding blocked or blunted all of these bile duct ligation-dependent changes by 45-73%. Together, the results indicate that cholestasis due to bile duct ligation causes liver injury by mechanisms involving oxidative stress. Polyphenols from C. sinenesis scavenge oxygen radicals and prevent activation of stellate cells, thereby minimizing liver fibrosis.     

LPS signaling enhances hepatic fibrogenesis caused by experimental cholestasis in mice

Although it is clear that bile acid accumulation is the major initiator of fibrosis caused by cholestatic liver disease, endotoxemia is a common side effect. However, the depletion of hepatic macrophages with gadolinium chloride blunts hepatic fibrosis. Because endotoxin is a key activator of hepatic macrophages, this study was designed to test the hypothesis that LPS signaling through CD14 contributes to hepatic fibrosis caused by experimental cholestasis. Wild-type mice and CD14 knockout mice (CD14(-/-)) underwent sham operation or bile duct ligation and were killed 3 wk later. Measures of liver injury, such as focal necrosis, biliary cell proliferation, and inflammatory cell influx, were not significantly different among the strains 3 wk after bile duct ligation. Markers of liver fibrosis such as Sirius red staining, liver hydroxyproline, and alpha-smooth muscle actin expression were blunted in CD14(-/-) mice compared with wild-type mice after bile duct ligation. Despite no difference in lymphocyte infiltration, the macrophage/monocyte activation marker OX42 (CD11b) and the oxidative stress/lipid peroxidation marker 4-hydroxynonenal were significantly upregulated in wild-type mice after bile duct ligation but not in CD14(-/-) mice. Increased profibrogenic cytokine mRNA expression in the liver after bile duct ligation was significantly blunted in CD14(-/-) mice compared with the wild type. The hypothesis that LPS was involved in experimental cholestatic liver fibrosis was tested using mice deficient in LPS-binding protein (LBP(-/-)). LBP(-/-) mice had less liver injury and fibrosis (Siruis red staining and hydroxyproline content) compared with wild-type mice after bile duct ligation. In conclusion, these data demonstrate that endotoxin in a CD14-dependent manner exacerbates hepatic fibrogenesis and macrophage activation to produce oxidants and cytokines after bile duct ligation.     

Enzyme activities as electron microscopic markers of bile and bile thrombi in the study of cholestasis

Summary An electron microscopical study of several phosphatases in liver tissue was made in different forms of cholestasis. The material included a biopsy from a case of giant cell hepatitis, dog liver after experimental common bile duct ligation, and rat liver under the same experimental conditions. A positive reaction of several phosphatases was noted in the sites of intra and extracellular accumulation of bile constituents. It is suggested that the activity of phosphatases, especially the alkaline phosphatase activity, can be useful as an electron microscopic marker of intracytoplasmic and intercellular bile constituents in the study of bile transport and bile regurgitation. The supposition is made that the intracytoplasmic bilirubin carrier protein can be of enzymatic character.     

Ultrastructure of cholinergic innervation in the cirrhotic liver in guinea pigs. Neurohistochemical and ultrastructural study

Hepatic cirrhosis was induced in guinea pigs by ligation of the common bile duct and innervation of the liver was studied by fluorescence histochemistry (glyoxylic acid method), acetylcholinesterase (AChE) neurohistochemistry (modified Karnovsky and Roots method), and transmission electron microscopy. In control animals the adrenergic terminals showed connections with endothelial cells, hepatocytes and fat-storing cells, but no cholinergic terminals were evident. Cirrhosis was present 6 weeks after the bile duct ligation and marked fibrosis, accompanied by bile duct proliferation, was evident in the portal areas. Numerous AChE-positive nerve fibers traversed the collagenous bundles in the fibrotic areas, and cholinergic terminals formed close contacts with fibroblasts. Each axon terminal was found to contain numerous small coreless vesicles and AChE-reaction products were confirmed in the space between a nerve terminal and a fibroblast. In contrast, fluorescence adrenergic nerve fibers and their terminals remained unchanged. This study demonstrates that parasympathetic cholinergic innervation participates in some stages in the development of hepatic cirrhosis.     

Bile acids in the rat: studies in experimental occlusion of the bile duct

Bile acids in the plasma, urine, and small intestine of adult male rats with occluded bile ducts have been studied using a method of high specificity for their determination. After bile duct ligation cholic acid rapidly accumulates in the plasma for 8 hr, remains high for a further 8 hr, and subsequently diminishes; bile acids disappear from the small intestine. During the first 12 hr after bile duct ligation the excretion of trihydroxy acids in the urine was 10 times that of the dihydroxy acids. Subsequently the two excretion rates became equal. Because bile acids have been implicated in the etiology of hepatic damage following bile duct ligation, studies have been made of the effect on the liver of removing (with cholestyramine) and supplementing (with cholic acid) the intestinal bile acid pool. The addition of cholestyramine to the stock diet prevented the rise in trihydroxy bile acids after bile duct ligation, but did not prevent the development of histological abnormalities in the liver. Supplementing the diet with cholic acid raised the plasma cholic acid levels but had little effect on the hepatic histological findings.     

Ductular reaction at the early terms of common bile duct ligation in the rats

Ductular reaction (DR) in bile duct ligated rats generally appears from 2nd day after biliary obstruction (BO). However, we show that increased amount of ductular profiles is evident already in 6 hours after BDL. The study aims to explain the origin of such an early DR in response to BO. Male Lewis rats were subjected to common bile duct ligation (CBDL) for 3, 6, 12 and 24 hours and sham operation. Liver samples were studied histologically, immunohistochemically (Ki67, pan-Cytokeratin /AE1 + AE3/ and OV-6) and by immunoblotting analyses. It appeared that number of ductular profiles increase in time-related manner after BO. These ductular profiles are formed by biliary epitheliocyte-like cells; No mitotic activity was revealed. Part of hepatocytes reveals pan-Cytokeratin positivity on 12 and 24 hours after BO. Total cytokeratins content at 24 hours after CBDL was 37% higher in comparison with control data. The significant increase was observed for the cytokeratins with molecular weights: 61, 56 and 40 KDa. Thus, early DR after BDL is mediated by widening of the existed finest biliary ramifications and is not associated with proliferation activities. This DR is accompanied by differentiation of hepatocytes toward bile duct-like cells.     

Bile canalicular barrier function and expression of tight-junctional molecules in rat hepatocytes during common bile duct ligation

Tight junctions of hepatocytes form the intercellular barrier between the blood circulation and bile flow. We focused on early stages of common bile duct ligation to observe changes in tight junctions without the irreversible changes seen after lengthy ligation. Common bile ducts of 12-week-old male rats were ligated for 6 h because, at this time point, no histological changes were observed. Serum bilirubin and bile acid levels began to increase 3 h after ligation and were restored to the control level immediately after surgical removal of the ligation. To examine the barrier of hapatocytes, horseradish peroxidase was injected via the femoral vein, and bile was collected for the first 10 min. A four-fold elevation of the secretion and concentration was observed in the bile of ligated rats compared with that of control animals. We next examined lanthanum permeability by perfusion fixation of the liver. At 6 h after ligation, both dilation of the bile canaliculi and partial loss of microvilli were commonly observed. There were dense deposits of lanthanum in almost all bile canaliculi of ligated rats. In control animals, neither dilation of the bile canaliculi nor loss of microvilli was detected, and only 44% of bile canaliculi exhibited deposits. An apparent increase of occludin mRNA expression was detected in livers after 6 h ligation, whereas the expression of claudin-1, -2, and -3 was not influenced by ligation. These results indicate that regulation of occludin gene expression is different from that of claudin-1, -2, and -3. The early phase of bile stasis employed in this study is thought to be an indispensable approach for understanding the precise regulation of tight junctions.     

Cholestasis-induced alterations of the trans- and paracellular pathways in rat hepatocytes

Bile secretion depends on the vectorial transport of solutes from blood to bile and involves three different pathways: transcellular pathways mediated by transport proteins distributed asymmetrically in the basolateral and canalicular plasma membrane and by transcytotic vesicles, and a paracellular pathway allowing selective diffusion through tight junctions. All three pathways are impaired differentially by extrahepatic (bile duct ligation) or intrahepatic (ethinyloestradiol) cholestasis. Ethinyloestradiol treatment leads to tight junctional defects that are less severe than those induced by bile duct ligation. Junctional impairment is reflected functionally in increased permeability for horseradish peroxidase and structurally by decreased strand numbers and increased junctional length, but not by alterations at the level of the individual strands. The parallelism of physiophical and morphological perturbations indicates a structure-function relationship in hepatocellular tight junctions. In addition, impaired functional integrity of tight junctions following bile duct ligation is reflected in a partial loss of hepatocellular surface polarity owing to redistribution of some, but not all, domain-specific plasma membrane antigens, which might mimic the behaviour of transport systems. After ethinyloestradiol treatment no alterations of surface polarity were observed. Thus, immunohistochemistry supports the view that ethinyloestradiol results in less severe impairment of the tight junctions than bile duct ligation. Finally, bile duct ligation, but not ethinyloestradiol, affects the transcytotic vesicular pathway; severe impairment of this is reflected in the absence of a late horseradish peroxidase peak in bile and also in the accumulation of pericanalicular vesicles that are immunopositive for canalicular membrane proteins and accessible for bulk phase endocytic markers. This view is supported by the disappearance of the pericanalicular vesicles simultaneously with the resumption of transcytotic horseradish peroxidase transport following release of ligation, a finding that indicates rapid restoration of this defect.This paper was presented at the symposium Metabolic Zonation of the Liver: New Answers to Old Questions, held in honour of Prof. Dr. D. Sasse's 60th birthday, 26 August 1994, in Basel     

Characterization of inducible nature of MRP3 in rat liver

We found previously that expression of multidrug resistance-associated protein (MRP) 3 is induced in a mutant rat strain (Eisai hyperbilirubinemic rats) whose canalicular multispecific organic anion transporter (cMOAT/MRP2) function is hereditarily defective and in normal Sprague-Dawley (SD) rats after ligation of the common bile duct. In the present study, the inducible nature of MRP3 was examined, using Northern and Western blot analyses, in comparison with that of other secondary active [Na(+)-taurocholic acid cotransporting polypeptide (Ntcp), organic anion transporting polypeptide 1 (oatp1), and organic cation transporter (OCT1)] and primary active [P-glycoprotein (P-gp), cMOAT/MRP2, and MRP6] transporters. alpha-Naphthylisothiocyanate treatment and common bile duct ligation induced expression of P-gp and MRP3, whereas expression of Ntcp, oatp1, and OCT1 was reduced by the same treatment. Although expression of MRP3 was also induced by administration of phenobarbital, that of cMOAT/MRP2, MRP1, and MRP6 was not affected by any of these treatments. Moreover, the mRNA level of MRP3, but not that of P-gp, was increased in SD rats after administration of bilirubin and in Gunn rats whose hepatic bilirubin concentration is elevated because of a defect in the expression of UDP-glucuronosyl transferase. However, the MRP3 protein level was not affected by bilirubin administration. Although the increased MRP3 mRNA level was associated with the increased concentration of bilirubin and/or its glucuronides in mutant rats and in SD rats that had undergone common bile duct ligation or alpha-naphthylisothiocyanate treatment, we must assume that factor(s) other than these physiological substances are also involved in the increased protein level of MRP3.     

Epidermal growth factor receptor in chronic bile duct obstructed rats: implications for maintenance of hepatocellular mass.

Changes of the number and properties of the epidermal growth factor (EGF) receptor occur during liver regeneration and may be of importance in the maintenance of hepatocellular mass in liver cirrhosis. We therefore studied the changes in the number and distribution of EGF receptor in the development of liver cirrhosis induced by bile duct ligation. Receptor binding assays demonstrated a marked decrease in the binding capacity of crude plasma membrane fractions from 45 +/- SD 16 to 19 +/- 10 fmol/mg protein (p < 0.001) in control and bile duct ligated livers, respectively while the Kd increased after 3 days of bile duct ligation from 0.5 +/- 0.2 to 1.4 +/- 0.6 nmol/l. Total receptor concentration in the same membrane fractions, as assessed by Western blot analysis, was not changed. The expression of EGF receptor mRNA was reduced to about one third of control levels after 28 days of bile obstruction. Immunohistochemistry, performed using monoclonal antibodies against EGF receptor, showed a strong labeling of cytoplasm (87 +/- 3% positive) and plasma membranes (84 +/- 24%) but no labeling of nuclei in control livers. In bile duct ligated rats, in contrast, cytoplasmic staining was decreased (15 +/- 12%) already after 3 days of bile obstruction; labeling of canalicular membranes and nuclei appeared after 14 days. The shift of EGF receptor from plasma membranes to nuclei supports the notion that EGF receptor is involved in the maintenance of hepatocellular mass in this model of liver cirrhosis. This concept is supported by the finding of decreased mRNA for EGF receptor presumably representing down-regulation as seen in regenerating rat liver.     

哺乳期BALB/c小鼠胆道梗阻模型的探索

目的探讨新生BALB/c小鼠胆道梗阻模型的建立,并与报告的新生BALB/c小鼠感染猕猴轮状病毒(RRV)模型小鼠生存曲线进行比较。方法将出生后5～7 d的BALB/c小鼠随机分为实验组和对照组,实验组进行胆总管结扎,然后关腹。对照组打开腹部后关腹不结扎胆总管。实验完成后每天观察小鼠的体重变化、无毛区皮肤颜色变化、小鼠存活天数以及在术后第5、10天时分别取小鼠肝脏做病理及免疫组化。结果小鼠在结扎后随着时间的延长,小鼠的体重及肝体比、无毛区皮肤颜色、存活天数、肝脏病理等都存在一定变化。小鼠体重增长逐渐缓慢,术后第2天就会出现无毛区的皮肤变黄,在尿道口会有淡黄色的液体并随后出现陶土样便。在术后第5天及第10天时取肝脏做肝体比有统计学差异(P≤0.05),小鼠在术后第10天左右会出现死亡高峰。结论新生BALB/c小鼠胆总管结扎模型是研究胆道梗阻的可靠动物实验,其生存曲线与报告的猕猴轮状病毒致胆道闭锁大体类似。     

双歧杆菌对梗阻性黄疸大鼠肠道细菌移位影响的研究

目的观察梗阻性黄疸大鼠肠道细菌移位状况及经胃肠道给予双歧杆菌对肠道细菌移位的影响。方法Wistar大鼠30只随机分为3组：假手术组（SO组）、梗阻性黄疸组（OJ组）及双歧杆菌组。模型制备后第10天检测各组肝功能指标及血浆内毒素水平,取肝、脾、肠系膜淋巴结等肠道外器官组织行细菌培养,光镜观察末端回肠黏膜变化。结果 OJ组较SO组肝功能指标明显改变（P〈0．05）,双歧杆菌组肝功能指标较OJ组改善。SO组血浆内毒素水平为（0．26±0．22）EU／ml,OJ组内毒素水平为（1．99±0．31）EU／ml,较SO组明显升高（P〈0．01）,双歧杆菌组血浆内毒素水平为（0．74±0．20）EU／ml,较OJ组明显降低（P〈0．01）。OJ组肝、脾、肠系膜淋巴结中细菌移位率高于另两组,其中肠系膜淋巴结细菌移位率为90％,明显高于SO组及双歧杆菌组（P〈0．05）。光镜显示OJ组肠黏膜萎缩,绒毛水肿,部分上皮细胞脱落;双歧杆菌组肠黏膜上皮改变较OJ组明显减轻。结论梗阻性黄疸时出现明显的细菌移位与内毒素血症。应用微生态制剂可保护梗阻性黄疸时小肠黏膜屏障功能,减少肠源性细菌移位及内毒素血症的发生。