Rat Model Of Cholestasis Research Articles

Correction to: Pulmonary inflammation, oxidative stress, and fibrosis in a rat model of cholestasis: the potential protective properties of the dipeptide carnosine

Correction to: Pulmonary inflammation, oxidative stress, and fibrosis in a rat model of cholestasis: the potential protective properties of the dipeptide carnosine

Efficacy of Zhuyu Pill Intervention in a Cholestasis Rat Model: Mutual Effects on Fecal Metabolism and Microbial Diversity.

Cholestasis is a clinical condition resulting from impaired bile flow. Currently, patients with cholestasis face several barriers in seeking diagnosis and treatment. Zhuyu Pill (ZYP) is an ancient classic formula of the Coptis-Evodia herb couples (CEHC), and has been used for cholestasis treatment in the clinic, however, its underlying biological activity in cholestasis remain to be clarified. In this study, an α-naphthyl-isothiocyanate (ANIT, 50 mg/kg)-induced rat model of cholestasis was treated with ZYP. Serum biochemical indices and histopathological evaluation was performed, together with the metabolomics analyses of feces and 16S rDNA sequencing of the fecal microbiota. We evaluated the anti-cholestatic activity of ZYP and investigated the mechanisms underlying its correlation with fecal microbiota and fecal metabolite regulation. The relationships between biochemical indices and changes in gene expression associated with liver injury, levels fecal metabolites, and composition of fecal microbiota were analyzed. The results showed that both high (1.2 g/kg) and low (0.6 g/kg) doses of ZYP could effectively improve biochemical parameters in the blood of cholestasis-induced rat models; the intervention effect of high dose ZYP was superior to that that of lower dose ZYP. Based on a metabolomics test of fecal samples, significantly altered metabolites in the ANIT and ZYP treatment group were identified. In total, 734 metabolites were differentially expressed, and whose biological functions were mainly associated with amino acid metabolism, steroid hormone biosynthesis, and bile secretion. In addition, sequencing of the 16S rDNA unit in fecal samples revealed that the ZYP could improve the fecal microbiota dysbiosis that ANIT had induced. Therefore, we conclude that ANIT altering of blood biochemical and metabolic profiles and of fecal microbiota could effectively be alleviated with ZYP treatment. This study contributes to the “TCM wisdom” applied in clinical diagnosis and treatment of cholestasis.

Cholestasis Alters miR-34c-5p Expression in the Testes of Male Wistar Rats

Background: Cholestasis is a pathophysiological condition, significantly reducing spermatozoa production. MiR-34c is highly expressed in adult male testicles and controls different stages of spermatogenesis. Objectives: Here, we aimed to investigate miR-34c expression in the testes of rat models of cholestasis. The expressions of THY-1, FGF-2, and CASP-3 genes, that are targeted by mirR-34c were also investigated. Methods: Cholestasis was induced in six adult rats via bile duct ligation. Four weeks after cholestasis induction, sera and testicular tissues were collected for further examinations. The levels of liver enzymes were measured using the ELISA. The structure of the testes was evaluated by histological examination. Total RNA was extracted from testes using a special kit and converted to cDNA. The expressions of miR-34c-5p, THY-1, FGF-2, and CASP-3 genes were determined by Real-Time PCR. Results: The serum levels of ALP, AST, and ALT were significantly elevated in the rat models of cholestasis (P < 0.001). Real-Time PCR revealed that the expressions of miR-34c-5p, THY-1, and FGF-2 genes decreased while CASP-3 gene was upregulated in the testes of cholestatic animals (all differences were significant at P < 0.05). Conclusions: Our study indicated that cholestasis was associated with reduced expression of miR-34c and altered expression of its target genes in the testis. Our results highlight the potential effects of cholestasis, a hepatobiliary disease, on testicular tissue function and male fertility.

Molecular Targets of Natriuretic Action of Prolactin in the Rat Model of Cholestasis of Pregnancy.

We analyzed the expression of molecular targets of natriuretic action of prolactin in different layers of the kidney in the rat model of cholestasis of pregnancy. Sodium bicarbonate cotransporter NBCe1 was most sensitive to the conditions of cholestasis and cholestasis of pregnancy: the expression NBCe1 mRNA and protein in the renal outer medulla decreased in comparison with the normal. All forms of cholestasis affected the mRNA expression of sodium-potassium chloride co-transporter NCC, α-subunit of the ENaCα epithelial sodium channel, and Nedd4-2 ubiquitin ligase in different layers of the kidney. The obtained data suggest that prolactin provides fine tuning of various sodium transporters in different parts of the nephron under pathological conditions.

Quercetin improves platelet function and ultrastructure in cholestatic liver injury in rats: Role of ORAI1 gene expression

Platelet dysfunction in liver diseases and especially in cholestatic liver diseases is not fully understood. The aim of the present work is to investigate the functional changes of platelets in bile duct ligated (BDL) rat model of cholestasis. The work was conducted on 30 male rats divided into 3 groups: Sham, BDL and quercetin-treated BDL (BDL-Q). Results: Rats from the BDL group showed prolonged bleeding time and diminished platelet aggregation in response to ADP (50 μmol/L), however, changes in platelet count were insignificant. Electron microscopic (EM) photos of platelets from BDL group showed signs of activation. vWF levels were decreased in the plasma of BDL group. ORAI1 gene expression was significantly reduced in their platelets after being exposed to ADP. In BDL-Q rats, bleeding time and platelet aggregation defects were improved. EM demonstrated a picture that is midway between sham and BDL platelets. vWF levels and ORAI1 gene expression increased significantly. ORAI1 expression in platelets was positively correlated to vWF levels. The study concluded that defective platelet function in BDL rat model of cholestasis is due to decrease ORAI1 gene expression and that quercetin administration enhances its expression and improves platelet function.

The protective effects of ursodeoxycholic acid and the selective cyclooxygenase-2 inhibitor celecoxib on liver damage in an experimental cholestasis model

Aim: Cholestasis leads to liver cell death, fibrosis, cirrhosis, and eventually liver failure. Ursodeoxycholic acid (UDCA) is the only Food and Drug Administration-approved treatment for cholestatic disorders. Hepatic cyclooxygenase-2 (COX-2) expression increases in various chronic liver diseases caused either by viruses or toxins. The present study was conducted to investigate the effects of UDCA and the selective COX-2 inhibitor celecoxib on inflammation and fibrogenesis in a rat model of cholestasis induced by bile duct ligation (BDL). Methods: Fifty Sprague–Dawley rats that underwent common BDL for 21 days were assigned to one of five treatment groups (sham-operation, BDL, daily UDCA treatment following BDL, daily celecoxib treatment following BDL, and daily celecoxib and UDCA combination treatment following BDL). Serum and liver samples were collected after 21 days. Fibrosis, ductular proliferation, and portal inflammation were scored in liver samples. Liver function tests were evaluated. Results: In comparison with the control group, the BDL group showed hepatic damage as evidenced by elevation in serum biochemical and histological changes such as ductular reaction, fibrosis, and inflammation. These pathophysiological changes were attenuated by chronic UDCA and selective COX-2 inhibitor celecoxib supplementation. Conlusion: Our findings indicate that the addition of Celecoxib to UDCA reduces liver inflammation and fibrosis and might be an effective supplemental therapy with UDCA for cholestatic diseases. The beneficial effects of chronic UDCA and Celecoxib supplementation may be associated with their potential cytoprotective, anti-oxidative and anti-inflammatory effects.

Glechoma hederacea extracts attenuate cholestatic liver injury in a bile duct-ligated rat model

Ethnopharmacological relevanceIn traditional Chinese medicine, Glechoma hederacea is frequently prescribed to patients with cholelithiasis, dropsy, abscess, diabetes, inflammation, and jaundice. Polyphenolic compounds are main bioactive components of Glechoma hederacea. Aim of the studyThis study was aimed to investigate the hepatoprotective potential of hot water extract of Glechoma hederacea against cholestatic liver injury in rats. Materials and methodsCholestatic liver injury was produced by ligating common bile ducts in Sprague-Dawley rats. Saline and hot water extract of Glechoma hederacea were orally administrated using gastric gavages. Liver tissues and bloods were collected and subjected to evaluation using histological, molecular, and biochemical approaches. ResultsUsing a rat model of cholestasis caused by bile duct ligation (BDL), daily oral administration of Glechoma hederacea hot water extracts showed protective effects against cholestatic liver injury, as evidenced by the improvement of serum biochemicals, ductular reaction, oxidative stress, inflammation, and fibrosis. Glechoma hederacea extracts alleviated BDL-induced transforming growth factor beta-1 (TGF-β1), connective tissue growth factor, and collagen expression, and the anti-fibrotic effects were accompanied by reductions in α-smooth muscle actin-positive matrix-producing cells and Smad2/3 activity. Glechoma hederacea extracts attenuated BDL-induced inflammatory cell infiltration/accumulation, NF-κB and AP-1 activation, and inflammatory cytokine production. Further studies demonstrated an inhibitory effect of Glechoma hederacea extracts on the axis of high mobility group box-1 (HMGB1)/toll-like receptor-4 (TLR4) intracellular signaling pathways. ConclusionsThe hepatoprotective, anti-oxidative, anti-inflammatory, and anti-fibrotic effects of Glechoma hederacea extracts seem to be multifactorial. The beneficial effects of daily Glechoma hederacea extracts supplementation were associated with anti-oxidative, anti-inflammatory, and anti-fibrotic potential, as well as down-regulation of NF-κB, AP-1, and TGF-β/Smad signaling, probably via interference with the HMGB1/TLR4 axis.

Role of Prolactin in the Regulation of Bicarbonates Biodynamics in Female Rat Model of Cholestasis of Pregnancy.

We studied possible involvement of prolactin in the regulation of bicarbonate biodynamics using female rat model of cholestasis of pregnancy induced by transplantation of the donor pituitary under the renal capsule of a recipient (hyperprolactinemia) and bile duct ligation (cholestasis). The concentration of bicarbonates in the bile and blood, their excretion, clearance, and reabsorption, as well as glomerular filtration rate and excretion of sodium ions were assessed. It was found that the main effect of prolactin was directed to the kidney-regulated pool of bicarbonates and consisted in stimulation of their clearance and inhibition of reabsorption, which led to a decrease in bicarbonate blood concentration. Parallel influence of prolactin on the clearance of bicarbonates and sodium ions was observed.

Untargeted Metabolomics Reveals Dose-Response Characteristics for Effect of Rhubarb in a Rat Model of Cholestasis.

Cholestasis is a serious manifestation of liver diseases with limited therapies. Rhubarb, a widely used herbal medicine, has been frequently used at a relatively large dose for treating cholestasis. However, whether large doses are optimal and the therapeutic mechanism remain unclear. To explore these questions, the anti-cholestatic effect of five doses of rhubarb (0.21, 0.66, 2.10, 6.60, and 21.0 g/kg) in an alpha-naphthylisothiocyanate (ANIT)-induced rat model of cholestasis was examined by histopathology and serum biochemistry. A dose-dependent anti-cholestatic effect of rhubarb (0.21–6.6 g/kg) was observed, and an overdose of 21.0 g/kg showed a poor effect. LC-MS-based untargeted metabolomics together with pathway analysis were further applied to characterize the metabolic alterations induced by the different rhubarb doses. Altogether, 13 biomarkers were identified. The dose-response curve based on nine important biomarkers indicated that doses in the 0.42–6.61 g/kg range (EC20–EC80 range, corresponding to 4.00–62.95 g in the clinic) were effective for cholestasis treatment. The pathway analysis showed that bile acid metabolism and excretion, inflammation and amino acid metabolism were altered by rhubarb in a dose-dependent manner and might be involved in the dose-response relationship and therapeutic mechanism of rhubarb for cholestasis treatment.

The effects and significances of the expression of the silent information regulator 1 protein under the influence of berberine in cholestatic kidney in rats

Objective To determinethe expression of silent information regulator 1(SIRT1), superoxide dismutase(SOD), malondialdehyde(MDA)and the glutathione(GSH), the aim of this study is to investigate the effects of the berberine to the expression of the SIRT1 protein and the protective effects to the renal function as related to cholestatic kidney injury in rats. Methods The animals were divided randomly into three groupls(n= 15).A rat model of cholestasis was established by bile duct ligation(BDL, B group)and compared with a Sham group receiving laparotomy without BDL(Sham, A group), and with the the BBR given respectively following BDL(BDL+ BBR, C group). All rats were sacrificed on the 7th day after BDL and the blood and kidney tissue samples were obtained.The expression of the SIRT1 proteins were analyzed by western blotting and the reverse transcriptase-polymerase chain reaction(RT-PCR)was performed to determine the mRNA expression of SIRT1 in all groups.The kits of SOD, MDA and GSH were used to detect the values in renal tissue and the apoptosis of the kidney cells was examined by Td T-mediated dUTP nick end labeling(TUNEL)staining. Results After the bile duct ligation, the model of cholestasis was established. Comparedto A group, the levels of the mRNA and proteins of the SIRT1,SOD and GSH were lower but the alanine transaminase(ALT), MDA and the apoptosis rate were higher in group B(P< 0.05). Compared C groups to B group, the levels of the mRNA and proteins of the SIRT1, SOD and GSH were higher but the MDA and the apoptosis rate were lower(P<0.05).The values of BUN,Cr,SOD,GSH,SIRT1 mRNA and protein and the rate of the A,Band C groups are:A group(3.14±0.53)mmol/L,(31.32±11.08)μmol/L, (19.45±2.41)nu/mg,(2.31±0.14)nmol/g,1.00±0.00, 0.27±0.01,(0.28±0.13)%; B group(8.37 ±1.57)mmol/L,(102.43±9.32)μmol/L,(5.96±1.43) nu/mg,(1.39±0.25) nmol/g, 0.51±0.05, 0.17±0.01,(19.36±2.56)%; C group(6.04±1.52) mmol/L,(78.58±13.63)μmol/L,(13.52±1.47) nu/mg,(1.97±0.19)nmol/g,0.79±0.04,0.22±0.01,(11.47±3.61)% the group A,B and C. Conclusion The present study demonstrates that the BBR could protect the kidney from the peroxide damage by increasing the expression of the SIRT1 which could promote the expression of the gene of SOD. And so the BBR plays a benefical role to resist peroxide damage and apoptosis in cholestatickidney injury. Key words: Berberine; Cholestasis; Silent information regulator 1; Superoxide dismutase

Effects of folic acid on dyslipidemia and serum homocysteine in a rat model of cholestasis and hepatic fibrosis.

The liver is the major site for storage and metabolism of folate. Folate deficiency is common in many liver diseases and causes severe effects on cellular metabolism and increases oxidative stress and the homocysteine (Hcy) level. The objective of this research was to investigate the effects of folic acid on dyslipidemia and serum Hcy concentrations in an experimental rat model of cholestasis. Eighty-one male Wistar rats were divided into nine groups: control, sham-operated, folic acid control, bile duct-ligated (BDL), and BDL+ folic acid groups. In folic acid treated groups, folic acid (1, 5, and 10 mg/kg body weight) was given orally for 28 days. After taking blood and liver samples, plasma lipid profiles and Hcy and hepatic reduced and oxidized glutathione concentrations were measured. Histopathological features of cholestasis were assessed by Masson's trichrome staining. Treatment of folic acid in BDL rats significantly prevented the progression of hepatic fibrosis and improved the serum and liver biochemical changes. These results suggest that folic acid protects the liver against cholestasis by reducing serum Hcy and by its antioxidant properties. Folic acid can be an important therapeutic intervention in dyslipidemia caused by cholestasis.

Role of GABAA receptor in modulation of acute thermal pain using a rat model of cholestasis

Increased activity of the endogenous opioid system in cholestasis results in analgesia. GABAA receptors have been ascribed both pronociceptive and antinociceptive roles in pain modulation. Considering the elevated endogenous opioid tone in cholestasis and the existence of close interaction between the GABAergic and opioidergic systems in pain control, the involvement of GABAA receptors in modulation of nociception in a model of elevated endogenous opioid tone, cholestasis, was investigated using muscimol and bicuculline as selective GABAA receptor agonist and antagonist respectively. Cholestasis was induced by ligation of the main bile duct using two ligatures and transsection of the duct between them. Cholestatic rats had increased tail-flick latencies (TFLs) compared to non-cholestatic rats. Administration of muscimol (0.2 and 0.4mg/kg, s.c.) and bicuculline (0.5 and 1mg/kg, s.c.) to the cholestatic groups significantly increased and decreased respectively TFLs compared to the saline treated cholestatic group. Muscimol antinociception in cholestatic animals was attenuated by co-administration of naloxone or bicuculline. Furthermore, the combination of bicuculline and naloxone completely reversed the increased TFLs of cholestatic rats back to the level of unoperated animals. Muscimol and bicuculline injections into non-cholestatic animals did not alter TFLs. At the doses used here, none of the drugs impaired motor coordination, as revealed by the rotarod test. This study shows the involvement of GABAA receptors in pain modulation during cholestasis in rats.

721 The Effect of the Red Wine Polyphenol Resveratrol on Cholestasis: Anti-Apoptotic, Mitochondrial Biogenesis and Autophagy

Background and AimsMitochondria are known to be involved in cholestatic liver injury. The potential protective effect of resveratrol in cholestatic liver injury and the possible roles of autophagy and apoptosis...

The effect of the red wine polyphenol resveratrol on a rat model of biliary obstructed cholestasis: involvement of anti-apoptotic signalling, mitochondrial biogenesis and the induction of autophagy

Mitochondria are known to be involved in cholestatic liver injury. The potential protective effect of resveratrol in cholestatic liver injury and the possible roles of autophagy and apoptosis induction in this process are not yet clear. The aim of this study is to determine whether resveratrol administration after bile duct ligation can reduce cholestasis-induced liver injury through modulating apoptosis, mitochondrial biogenesis and autophagy. A rat model of cholestasis was established by bile duct ligation (BDL) and compared with a sham group receiving laparotomy without BDL, with resveratrol or control treatments following BDL. The expression of proteins involved in the apoptotic and autophagic pathways were analyzed by western blotting. Apoptosis was examined by TUNEL staining. In the resveratrol/BDL group LC3-II upregulation persisted for 1-7 days, Bax was downregulated and catalase was upregulated at 3-7 days after resveratrol treatment. The decline in mitochondrial DNA copy number was reversed at 3-7 days. Caspase 3 expression was significantly downregulated at 3-7 days in the resveratrol group. TUNEL staining showed significant numbers of apoptotic liver cells appeared in livers 3-7 days after BDL and that was decreased by resveratrol treatment. Our results indicate that early resveratrol treatment reverses impaired liver function within hours of BDL.

Suppression of the HPA axis during extrahepatic biliary obstruction induces cholangiocyte proliferation in the rat

Cholestatic patients often present with clinical features suggestive of adrenal insufficiency. In the bile duct-ligated (BDL) model of cholestasis, the hypothalamic-pituitary-adrenal (HPA) axis is suppressed. The consequences of this suppression on cholangiocyte proliferation are unknown. We evaluated 1) HPA axis activity in various rat models of cholestasis and 2) effects of HPA axis modulation on cholangiocyte proliferation. Expression of regulatory molecules of the HPA axis was determined after BDL, partial BDL, and α-naphthylisothiocyanate (ANIT) intoxication. The HPA axis was suppressed by inhibition of hypothalamic corticotropin-releasing hormone (CRH) expression by central administration of CRH-specific Vivo-morpholinos or by adrenalectomy. After BDL, the HPA axis was reactivated by 1) central administration of CRH, 2) systemic ACTH treatment, or 3) treatment with cortisol or corticosterone for 7 days postsurgery. There was decreased expression of 1) hypothalamic CRH, 2) pituitary ACTH, and 3) key glucocorticoid synthesis enzymes in the adrenal glands. Serum corticosterone and cortisol remained low after BDL (but not partial BDL) compared with sham surgery and after 2 wk of ANIT feeding. Experimental suppression of the HPA axis increased cholangiocyte proliferation, shown by increased cytokeratin-19- and proliferating cell nuclear antigen-positive cholangiocytes. Conversely, restoration of HPA axis activity inhibited BDL-induced cholangiocyte proliferation. Suppression of the HPA axis is an early event following BDL and induces cholangiocyte proliferation. Knowledge of the role of the HPA axis during cholestasis may lead to development of innovative treatment paradigms for chronic liver disease.

Modification of hepatic iron metabolism induced by pravastatin during obstructive cholestasis in rats

Aims To evaluate iron biochemistry and contributing liver mechanisms during obstructive cholestasis and pravastatin treatment in rats. Main methods A rat model of cholestasis induced by bile duct ligation (BDL) was used for the study. The detection of iron and the expression of relevant molecules were performed one week after surgery in the control, and cholestatic animals after treatment with either saline or pravastatin (1 mg/kg/day). Key findings Saline-administered BDL rats showed, in comparison to sham-operated animals, a significant increase in plasma iron concentration, increased liver protein content of heme oxygenase-1 (HO-1) and a decline in the expression of hepcidin. Ferroportin 1 expression was increased with a simultaneous reduction in intrahepatic iron concentration. The administration of pravastatin to BDL animals attenuated proliferation changes in liver parenchyma, prevented HO-1 induction, restored hepatic mRNA hepcidin expression to control levels and induced the expression of ferritin, transferrin receptors (TfR1/2) and divalent metal transporter-1. This was accompanied by an increased content of intrahepatic iron when compared to the BDL animals, and a reduction of hyperbilirubinemia. Significance Cholestasis-induced increase in plasma and decrease in hepatic iron levels were associated with up-regulation of liver HO-1 and ferroportin 1. Pravastatin alleviated cholestatic liver impairment and raised liver iron content by modulation of heme catabolism and an increase of hepatic iron uptake and storage capacity.

Glucocorticoid Modulates High-Mobility Group Box 1 Expression and Toll-Like Receptor Activation in Obstructive Jaundice

Obstructive jaundice is associated with bacterial translocation and inflammatory cytokine induction. It is unknown if toll-like receptors (TLRs) and their upstream molecule high mobility group box-1 (HMGB1) are involved in the pathogenetic mechanism and if glucocorticoid is effective in modulating the process. A rat model of cholestasis by ligation of the extrahepatic bile duct (BDL) for 2 wk was created. TLRs, interferon regulatory factors (IRFs), IL-6, IL-8, antimicrobial peptide β-defensin, and cathelicidin, as well as HMGB1 expressions were studied by using real-time quantitative reverse transcription-polymerase chain reaction, immunohistochemistry, Western blotting, and enzyme-linked immunosorbent assay (ELISA). Glucocorticoid treatment was applied to a group of BDL rats. Obstructive jaundice for 2 wk was associated with significant up-regulation of TLR1, 2, 4, 6, 7, and 9 mRNA expressions. There were significant increases of liver IRF5, IL-6, and β-defensin 1 mRNA levels in the BDL rats than in the sham and nonoperative control rats, which were associated with significant increase of immunoreactive IRF5 protein staining in the nucleus of Kupffer cells and neutrophils. Hepatic HMGB1 expression and release into serum were significantly elevated in the cholestatic rats than in the sham and control rats. Glucocorticoid treatment significantly decreased hepatic HMGB1 expression and release into serum, which was associated with significantly decreased hepatic TLR4 mRNA expression in the cholestatic rats. The results indicate that obstructive jaundice may induce hepatic HMGB1 expression with activation of TLR4 and a number of downstream signaling molecules, which can be reversed by glucocorticoid administration.

Dexamethasone decreases cholestatic liver injury via inhibition of intrinsic pathway with simultaneous enhancement of mitochondrial biogenesis

Background Mitochondria are known to be involved in cholestatic liver injury. We tested the hypothesis that glucocorticoids can modulate mitochondrial function to alleviate cholestatic liver injury. Methods A rat model of cholestasis was established by bile duct ligation (BDL), with a sham group receiving laparotomy without BDL, and a group receiving dexamethasone (DEX) treatment after BDL. Results The liver function including total bilirubin levels, alanine transaminase and aspartate transaminase activities was significantly improved in the DEX treatment group in comparison to the BDL group. There was a significant upregulation of liver peroxisome proliferator-activated receptor γ coactivator-1α and mitochondrial transcriptional factor A protein between 6 and 72 h was found in the DEX group. DEX treatment significantly down-regulated Bax, caspase 9 and caspase 3 expression induced by BDL at 24–72 h, but had little effect on the expression of caspase 8, Bcl 2, Fas and Fas-FasL complex. Consequently, the number of apoptotic liver cells in the DEX group was significantly less than in the BDL group at 72 h. Conclusion Our results indicate that glucocorticoids decreases cholestatic liver injury within hours after BDL. Early glucocorticoids treatment can enhance the mitochondrial biogenesis and modulate the intrinsic but not extrinsic pathway of apoptosis following BDL.

Hepatocyte aquaporins in bile formation and cholestasis

Bile formation by hepatocytes is an osmotic secretory process that is ultimately dependent on the biliary secretion of osmotically-active solutes (mainly bile salts) via specialized canalicular transporters as well as on the water permeability of the canalicular plasma membrane domain. Hepatocytes express aquaporins, a family of membrane channel proteins that facilitate the osmotically-driven movement of water molecules. Aquaporin-8 (AQP8), localized to canalicular membranes, modulates membrane water permeability providing a molecular mechanism for the osmotically-coupled transport of solute and water during bile formation. There is experimental evidence suggesting that defective hepatocyte AQP8 expression leads to alterations in normal bile physiology. Thus, AQP8 protein is downregulated (and canalicular water permeability decreased), in established rat models of cholestasis, such as sepsis-associated cholestasis, estrogen-induced cholestasis and extrahepatic obstructive cholestasis. Moreover, AQP8 gene silencing in the human hepatocyte-derived cell line HepG2 inhibits canalicular water secretion. Based on current knowledge, it is conceivable that cholestasis results from a mutual occurrence of impaired solute transport and AQP8-mediated decrease of canalicular water permeability.

762 The Role in Cell Death in Cholestasis Murine M.-M.

Objective: We find that the biogenesis of mitochondria is response to the early stage of cholestasis with internal pathway. The regulation pathogenesis of the liver cell apoptosis in this early stage in cholestatic liver injury is not clear. Methods: A rat model of cholestasis was established by bile duct ligation (BDL), with simultaneous creation of the sham group receiving laparotomy without BDL. Liver LC3B1, LC3B2, Beclin-1, caspase 9 protein expression was analyzed by western blotting. The ATF6, IRE1, BIP RNA level was measured by realtime polymerase chain reaction. Results: The liver LC3B-2 and LC3B2/LC3B1 ratio at 6-72 hours with caspase 9 activity and Beclin-1 levels at 72 hours significant upregulated. The ATF6, IRE1, BIP significantly decreased at 24- 72 hours. Conclusions: Our results indicate that regulation of the liver biogenesis is within a few hours after complete bile duct obstruction. Early murine cholestatic liver injury is via autophagy pathway.