Macrophage phenotype during cholestatic injury and repair: the persistent inflammatory response

Platelet C-Type Lectin-Like Receptor 2 Reduces Cholestatic Liver Injury in Mice

Cholestatic liver injury leads to liver dysfunction. The available evidence suggests that platelets can either promote or reduce liver injury and fibrosis. This study focused on the functions of the C-type lectin-like receptor 2 (CLEC-2), a new special platelet receptor that binds with podoplanin-activating platelets. The role of CLEC-2 and podoplanin in cholestatic liver injury was investigated. Mice were injected intraperitoneally with weekly doses of anti-CLEC-2 antibody (2A2B10) to achieve effective CLEC-2 inhibition in their platelets. Next, left and middle hepatic bile duct ligation (BDL) procedures were performed, and mice were euthanized 1 week later (2A2B10-BDL group). In addition, mice were prepared for control groups, and relevant histological and laboratory variables were compared among these groups. The inhibition of CLEC-2 resulted in increasing hepatocellular necrosis, hepatic inflammation, and liver fibrosis. In addition, podoplanin was strongly expressed in hepatic sinusoidal endothelial cells in BDL-treated mice. Moreover, in 2A2B10-BDL mice, total plasma bile acid levels were significantly increased. In summary, podoplanin is expressed on hepatic sinusoidal endothelial cells upon BDL. Platelets bind with podoplanin via CLEC-2 and become activated. As a result, the total bile acid pool is decreased. Therefore, the CLEC-2-podoplanin interaction promotes liver protection and inhibits liver fibrosis after cholestatic liver injury.

Quantitative Contrast-Enhanced Ultrasound by Sonazoid in the Early Diagnosis of Biliary Atresia: An Experimental Study of Rats With Bile Duct Ligation

We aimed to investigate the feasibility of quantitative Sonazoid contrast-enhanced ultrasound (CEUS) in the diagnosis of biliary atresia (BA) at an early disease stage. First, liver tissue from 10 patients with BA and 10 patients with infantile hepatitis syndrome (IHS) was immunostained with cluster of differentiation 68 (CD68) to compare Kupffer cell counts. Then, quantitative Sonazoid CEUS was performed to evaluate the hyperplasia of the artery branches during the artery phase and changes in Kupffer cell counts during the Kupffer phase in a rat model of BA (common bile duct ligation). Based on our results, liver enhancement from Kupffer cells in BA patients was significantly higher than that in IHS patients (p = 0.026 < 0.05). Furthermore, quantitative CEUS showed that the liver enhancement intensity of rats with bile duct ligation was substantially greater than that of rats without bile duct ligation during the artery phase 3 d post-operation and the Kupffer phase 5 d post-operation. The increased enhancement intensity in the Kupffer phase was in agreement with the increase in Kupffer cell counts in pathologic staining (18/20, 90%). In conclusion, quantitative Sonazoid CEUS can detect the hyperplasia of artery branches in artery phase and the increase of Kupffer cells in Kupffer phase in the liver of BA rats at an early disease stage. Therefore, Sonazoid CEUS could potentially be a valuable non-invasive alternative for the diagnosis of BA.

Contrasting responses of Kupffer cells and inflammatory mononuclear phagocytes to biliary obstruction in a mouse model of cholestatic liver injury

BACKGROUND

Biliary obstruction and cholestasis are serious complications of many liver diseases. Although resident hepatic macrophages (Kupffer cells) are frequently implicated in disease progression, most studies fail to differentiate the contribution of Kupffer cells and inflammatory mononuclear phagocytes (iMNPs) that infiltrate the liver subsequent to obstruction.

AIM

This study was undertaken to examine the roles and potential interactions of these two disparate mononuclear phagocyte populations in hepatic injury attending cholestasis.

METHODS

Female, C57Bl/6 mice were injected with magnetic beads on day 3 prior to sham operation or bile duct ligation (BDL) to facilitate subsequent Kupffer cell isolation. Three days post-surgery, animals were euthanized, and bead-containing Kupffer cells and iMNPs were separated, purified and analysed. To examine the ability of Kupffer cells to modulate iMNP activity, iMNPs were isolated from the livers of intact and Kupffer cell-depleted mice on day 3 post-surgery and compared.

RESULTS

Purified Kupffer cells and iMNP populations obtained from BDL mice exhibited heterogeneous morphologies rendering them visually indistinguishable. iMNPs, however, were characterized by the increased expression of Ly-6C and CD11b and the elevated production of chemokines/cytokines characteristic of inflammatory cells. In the absence of Kupffer cells, iMNPs immigrating to the liver following BDL exhibited significant decreases in CD11b and Ly-6C expression, and in pro-inflammatory chemokine/cytokine production.

CONCLUSIONS

Kupffer cells and iMNPs exhibit disparate biological responses to biliary obstruction and cholestasis. Kupffer cells play a key role in regulating iMNP influx and activity.

α-SMA overexpression associated with increased liver fibrosis in infants with biliary atresia

OBJECTIVE

The mechanisms responsible for increased collagen production and hepatic fibrosis in biliary atresia (BA) remain largely unknown. We evaluated α-smooth muscle actin (α-SMA) expression in liver and the porta hepatis in infants with BA.

METHODS

Immunohistochemical staining for α-SMA and CD68 in the BA liver and porta hepatis was performed. A semiquantitative 3-grade staging system was employed to estimate liver fibrosis. The densities of CD68 in BA liver and the levels of direct bilirubin were assessed in relation to α-SMA expression.

RESULTS

α-SMA was found to be overexpressed in epithelial cells and in periductular collagen fibers. The expression in infants with BA was higher than that in the control group (P < 0.05). The amount of α-SMA in BA was positively correlated with liver fibrosis scores (r = 0.549, P = 0.022). The levels of α-SMA in the liver of BA were negatively related with improvements in direct bilirubin levels, 3 months postoperatively (r = -0.653, P = 0.029). The correlation between the α-SMA and CD-68 expression was not significantly different (r = 0.444, P = 0.057).

CONCLUSIONS

The expression of α-SMA in BA liver is higher than that in contro1 group. α-SMA expression is negatively correlated with the reduction of direct bilirubin, 3 months postoperatively, probably due to fibrosis or cirrhosis affecting the entire biliary system.

Protective effect of Urtica dioica on liver damage induced by biliary obstruction in rats

The aim of this study was to evaluate the possible protective effects of Urtica dioica (UD) against liver damage in the common bile duct-ligated rats. A total of 24 male Sprague Dawley rats were divided into three groups, namely, control, bile duct ligation (BDL) and BDL + received UD groups, containing eight animals in each group. The rats in UD-treated groups were given UD oils (2 ml/kg) once a day intraperitoneally for 2 weeks starting 3 days prior to BDL operation. The change demonstrating the bile duct proliferation and fibrosis in expanded portal tracts includes the extension of proliferated bile ducts into the lobules; inflammatory cell infiltration into the widened portal areas were observed in BDL group. Treatment of BDL with UD attenuated alterations in liver histology. The α-smooth muscle actin, cytokeratin-positive ductular proliferation and the activity of terminal deoxynucleotidyl transferase dUTP nick end labeling in the BDL were observed to be reduced with the UD treatment. The data indicate that UD attenuates BDL-induced cholestatic liver injury, bile duct proliferation and fibrosis.

Glucocorticoid modulates high-mobility group box 1 expression and Toll-like receptor activation in obstructive jaundice

BACKGROUND

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.

MATERIALS AND METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

Scaffolds containing growth factors and extracellular matrix induce hepatocyte proliferation and cell migration in normal and regenerating rat liver

BACKGROUND & AIMS

Intrahepatic drug delivery from implantable scaffolds is being developed as a strategy to modulate growth and enhance regeneration at the time of liver resection. In this study we examine the effects of scaffolds containing hepatocyte growth factor, epidermal growth factor, fibroblast growth factor 1, fibroblast growth factor 2, and liver-derived extracellular matrix (L-ECM) when implanted into normal and partially hepatectomized rat livers.

METHODS

Scaffolds loaded with combinations of growth factors and L-ECM were implanted into normal livers (controls=L-ECM, polymer or sham) and livers following partial hepatectomy (controls=partial hepatectomy or sham). The primary end points were hepatocyte DNA synthesis and liver tissue penetration into scaffolds. Secondary end points included non-parenchymal cell DNA synthesis, liver weight analysis, liver function, and histological characterisation of the peri-implant parenchyma.

RESULTS

Four days after implantation in normal livers, there was significantly more hepatocyte proliferation around growth factor scaffolds than controls. Seven days after implantation, there was significantly more tissue penetration into growth factor scaffolds than control scaffolds. ED-1 and desmin positive cells were present in the pores of scaffolds. Two days after partial hepatectomy, there was significantly more hepatocyte proliferation around scaffold implanted livers than after partial hepatectomy alone.

CONCLUSIONS

Growth factors and L-ECM accelerated non-parenchymal cell migration into scaffolds and increased hepatocyte and non-parenchymal cell proliferation around them. These results demonstrate the potential for intrahepatic implantation of scaffolds containing growth factors and L-ECM to modulate growth in the normal and regenerating liver.

Biliary intervention aggravates cholestatic liver injury, and induces hepatic inflammation, proliferation and fibrogenesis in BDL mice

Obstructive cholestasis occurs in various clinical situations, whose pathological process is complex and not well known. The present study was initiated to display the complex and multifaceted pathological process caused by obstructive cholestasis in bile duct-ligated mice. Adult mice were bile-duct-ligated or sham-operated, and serum and liver tissues were collected at the indicated time points. Automatic biochemical analyzer was used to monitor serum biochemical index; TUNEL, HE staining, immunohistochemistry and Real-time PCR were employed to evaluate liver apoptosis, necrosis, inflammation, as well as proliferation and fibrosis. Our results demonstrated that obstructive cholestasis led to elevated serum biochemical indicators, with ALT peaking at day 3, indicative of acute hepatic dysfunction. Meanwhile, the number of TUNEL-positive cells increased significantly, and by 2 weeks, mild to moderate necrosis became apparent in BDL mouse livers, which consequently aggravated hepatic inflammatory responses as was demonstrated by increased expression of KC-1, MIP-2, ICAM-1 and MPO in BDL mouse livers. Moreover, proliferative hepatocytes around periportal areas, manifested by enhanced cell mitosis and elevated expression of proliferative markers such as PCNA and Ki67, increased significantly after BDL, while increased CK-19-positive cells in bile ducts indicated bile duct hyperplasia. By 2 weeks, numerous α-SMA-positive cells and Sirius-stained collagen were observed, indicative of hepatic stellate cells (HSC) activation and fibrogenesis. In conclusion, biliary intervention led to a multifaceted hepatic pathological process characterized by aggravated liver injury and inflammatory reaction with enhanced cellular proliferation and fibrogenesis.

Neutrophil depletion blocks early collagen degradation in repairing cholestatic rat livers

Biliary obstruction results in a well-characterized cholestatic inflammatory and fibrogenic process; however, the mechanisms and potential for liver repair remain unclear. We previously demonstrated that Kupffer cell depletion reduces polymorphonuclear cell (neutrophil) (PMN) and matrix metalloproteinase (MMP)8 levels in repairing liver. We therefore hypothesized that PMN-dependent MMP activity is essential for successful repair. Male Sprague-Dawley rats received reversible biliary obstruction for 7 days, and the rat PMN-specific antibody RP3 was administered 2 days before biliary decompression (repair) and continued daily until necropsy, when liver underwent morphometric analysis, immunohistochemistry, quantitative RT-PCR, and in situ zymography. We found that RP3 treatment did not reduce Kupffer cell or monocyte number but significantly reduced PMN number at the time of decompression and 2 days after repair. RP3 treatment also blocked resorption of type I collagen. In addition, biliary obstruction resulted in increased expression of MMP3, MMP8, and tissue inhibitor of metalloproteinase 1. Two days after biliary decompression, both MMP3 and tissue inhibitor of metalloproteinase 1 expression declined toward sham levels, whereas MMP8 expression remained elevated and was identified in bile duct epithelial cells by immunohistochemistry. PMN depletion did not alter the hepatic expression of these genes. Conversely, collagen-based in situ zymography demonstrated markedly diminished collagenase activity following PMN depletion. We conclude that PMNs are essential for collagenase activity and collagen resorption during liver repair, and speculate that PMN-derived MMP8 or PMN-mediated activation of intrinsic hepatic MMPs are responsible for successful liver repair.

The effect of aminoguanidine against cholestatic liver injury in rats

We investigated the protective role of aminoguanidine (AG) in rat liver injury induced by chronic biliary obstruction. Secondary biliary cirrhosis was induced by bile duct ligation for 14 days. Swiss albino rats were divided into three groups: Common bile duct ligated (CBDL) rats; Group A, CBDL rats treated with AG as Group B and simple laparotomy group known as the Sham group; Group C. Group B received 200 mg/kg of AG intraperitoneally daily throughout 14 days. The present data showed decreased gama glutamyl transferase (GGT), aspartate aminotransferase (AST), bilirubin and alanine aminotransferase (ALT) levels in the AG treated rats, when compared with CBDL rats (p < 0.05). In the AG treated rats, tissue levels of malondialdehyde (MDA) were significantly lower than that in CBDL rats (p < 0.001). Although the levels of glutathione (GSH) in AG treated rats were higher and myeloperoxidase (MPO) were lower than that in CBDL rats, the difference was not statistically significant (p > 0.05). The levels of interleukin-1alpha (IL-1alpha) and tumor necrosis factor-alpha (TNF-alpha) were significantly lower and although the levels of interleukin-6 (IL-6) were lower in AG treated rats than that in CBDL rats, the difference was not statistically significant. Administration of AG in the rats with biliary obstruction resulted in inhibition of ductular proliferation and portal inflammation. The present study demonstrates that intraperitoneal administration of AG in CBDL rats maintains antioxidant defenses, reduces liver oxidative and cytokine damage and ductular proliferation and portal inflammation. This effect of AG may be useful in the preservation of liver injury in cholestasis.

Glucocorticoid pretreatment suppresses chemokine expression and inflammatory cell infiltration in cholestatic rats receiving biliary intervention

AIM

Biliary intervention may augment chemokine expression and inflammatory cell infiltration and aggravates liver injury in cholestatic rats. We tested the efficacy of glucocorticoid pretreatment to prevent the complications.

METHODS

A model of biliary intervention was established in rats without (sham) or with bile duct ligation (BDL). Before biliary intervention, rats were randomly assigned to receiving intravenous injection of dexamethasone (DX group) or normal saline (NS group). Plasma levels of monocyte chemoattractant protein-1 (MCP-1) and macrophage inflammatory protein-2 (MIP-2) were measured with enzyme-linked immunosorbent assay, and liver messenger RNA of these chemokines was quantified with real-time quantitative reverse transcriptase-polymerase chain reaction. Monocytes, Kupffer cells, and neutrophils in the rat liver were characterized with antibodies to ectodermal dysplasia 1 (ED1), ED2, and myeloperoxidase, respectively.

RESULTS

By 3 hours after biliary intervention, plasma MCP-1 and MIP-2 proteins in BDL-NS rats were significantly higher than in BDL-DX. At 3 hours, liver MCP-1 and MIP-2 messenger RNA levels were significantly upregulated in BDL-NS than in BDL-DX. The amount of ED1-, ED2- and myeloperoxidase-staining cells were significantly greater in BDL-NS than in BDL-DX. Most of the changes returned to baseline levels by 24 hours.

CONCLUSION

Glucocorticoid pretreatment suppresses chemokine expression and inflammatory cell infiltration, which may consequently alleviate liver injury in cholestatic rats receiving biliary intervention.

The NF-kappaB inhibitors attenuate hepatic injury in bile duct ligated rats

Cholestasis-induced liver injury during bile duct obstruction causes an inflammatory response and this inflammatory process may be an important source of tissue injury. We hypothesized that NF-kappaB inhibition would decrease liver injury in a rat model of extrahepatic biliary obstruction. A total of 40 female rats of Sprague-Dawley strain were allocated to four groups. First group was sham operated control. The second group underwent common bile duct ligation (BDL) and was monitored for 10 days. Third group of rats underwent BDL and received pyrrolidine dithiocarbomate (PDTC) at a dose of 100 mg/kg/day intraperitoneally. Fourth group underwent BDL and received sulfasalazine at a dose of 100 mg/kg b.w. Both inhibitors were administered once a day throughout last 7 days of the experimental period. Rats were terminated 10 days after sham operation or BDL. Aspartate aminotransferase, alanine aminotransferase, gamma-glutamil transpeptidase, and tumor necrosis factor-alpha levels were elevated in the BDL group as compared to the control group, while this increase was significantly decreased by treatment with PDTC and sulfasalazine (P < 0.05). Hepatic GSH, SOD and catalase levels were significantly depressed by BDL, but were elevated back to control levels in NF-kappaB inhibitor-treated BDL groups. Increases in tissue free radical and MDA levels and MPO activity due to BDL were reduced back to control levels by NF-kappaB inhibitor treatment (P < 0.05). Similarly histological damage in the BDL rats was reduced by treatments. These results indicate that inhibitors of NF-kappaB activity such as PDTB and sulfasalazine exert a therapeutic effect on cholestatic liver injury in rats with BDL through anti-inflammatory and antioxidant actions.

Expression of the neurotrophin receptor TrkB in the mouse liver

Neurotrophins acting through Trk signal-transducing receptors play essential roles in the nervous system, and probably in some non-neuronal tissues. In the present study, we used RT-PCR, Western-blot and immunohistochemistry to investigate the occurrence and cellular localization of TrkB in the mouse liver, from newborns to 6 months. Furthermore, the structure of the liver in mice carrying a mutation in the trkB gene, resulting in a non-functional protein, was studied. The analysis of the DNA sequence showed that hepatic trkB gene is identical to the cerebral one, and TrkB mRNA and TrkB full-length protein (145 kDa) were detected at all the ages sampled. Immunohistochemistry revealed age-dependent changes in the pattern of TrkB expression. From 0 to 15 days, the TrkB was detected in morphologically and immunohistochemically identified monocyte-macrophage-dendric cells scattered throughout the organ, while in animals 3- and 6-months-old it was restricted to nerve fibres. Interestingly, there was a parallelism between TrkB expression by monocyte-macrophage-dendric cells and the presence of hepatic erythroblastic islands. In agreement with a possible role of TrkB on hepatic haematopoiesis, the liver of 15 days old TrkB (-/-) mice still contained erythroblastic islands, whereas they were absent in the wild-type littermates. Another striking finding was the absence of nerve profiles in the TrkB (-/-) animals. All together, present results support the role of TrkB in the murine liver in maintaining the innervation of the organ, and more importantly throughout an unknown mechanism in controlling the hepatic haematopoietic function.

Repair after cholestatic liver injury correlates with neutrophil infiltration and matrix metalloproteinase 8 activity

BACKGROUND

Although timely surgical treatment of liver disease can interrupt inflammation and reduce fibrosis, the mechanisms of repair are unknown. We questioned whether these mechanisms of repair include changes in the inflammatory infiltrate and associated biological activity of matrix metalloproteinases (MMPs) 8 and 2.

METHODS

Rats (n >or= 3) underwent biliary ductal suspension for 7 days followed by decompression. Livers were collected after 7 days of obstruction (d0) and after 2, 5, and 7 days of repair (d2, d5, d7, respectively), and assessed morphometrically for collagen, polymorphonuclear cells (PMNs), Kupffer cells (KCs), and inflammatory mononuclear phagocytes (MNPs). In situ zymography was performed by using fluorogenic substrates for MMP-8 and MMP-2 to spatially localize enzymatic activity.

RESULTS

Cholestatic injury resulted in significantly elevated (P <or= .001) collagen deposition (3-fold), and elevated numbers of MNPs (10-fold), KCs (5-fold), and PMNs (4-fold), compared with shams. PMNs remained elevated through d7, while collagen deposition, KCs, and MNPs returned to sham levels by d2. In situ zymography showed no significant changes in MMP-2 activity after cholestatic injury and repair. MMP-8 activity was significantly (P <or= .05) elevated only during repair. Activity was localized to fibrotic portal triads containing PMNs.

CONCLUSIONS

Cholestatic injury results in increased fibrosis, MNPs, KCs, and PMNs but no MMP-2 or MMP-8 activity. Biliary decompression results in increased MMP-8 activity co-localized to areas of portal fibrosis and PMN accumulation. We conclude that secretion of MMP-8 by neutrophils may play a critical role in resolving the fibrotic scar generated during cholestasis.

Biliary intervention augments chemotactic reaction and aggravates cholestatic liver injury in rats

BACKGROUND

Intervention of the biliary system is frequently done in patients with obstructive jaundice and is associated with significant morbidity and mortality. The pathogenesis is unknown.

MATERIALS AND METHODS

A rat model of bile duct ligation (BDL) for 2 weeks was established in which biliary intervention was feasible by injection of normal saline through an indwelling catheter in the bile ducts. Plasma levels of C-C chemokine MCP-1 and C-X-C chemokine MIP-2 were measured by using ELISA. Blood monocytes, Kupffer cells, and neutrophils in the liver were characterized with antibodies to ED1, ED2, and myeloperoxidase (MPO). Lipid peroxidation was measured by malondialdehyde contents and apoptosis by TUNEL stain of the liver.

RESULTS

Biliary intervention resulted in an increase of plasma MCP-1 and MIP-2 proteins by 1 h, which declined to normal level by 3 h in both sham and BDL rats. The levels in BDL rats were significantly higher than in sham at most points. There was a transient increase of ED1- and ED2-positive cells and MPO-staining cells in sham rat liver by 1 h after intervention. ED2-positive cells increased significantly by 1 h, while ED1- and MPO-positive cells decreased, yet insignificantly after intervention in BDL rats. The cell counts in BDL were constantly higher than in sham. Malondialdehyde increased precipitously in BDL by 3 h and was significantly higher than in sham throughout the study period. Parenchymal liver injury, manifested by elevated ALT, as well as apoptosis and necrosis of liver cells, was significantly increased in BDL rats, but not in sham rats.

CONCLUSION

Biliary intervention augments chemokine expression, precipitates lipid peroxidation, and aggravates liver injury in cholestatic rats.

Protective effect of polyunsaturated phosphatidylcholine on liver damage induced by biliary obstruction in rats

BACKGROUND/PURPOSE

Persistent inflammatory response secondary to congenital or acquired biliary choleastasis plays an important role in the pathophysiology of hepatic tissue damage. The polyunsaturated fatty acids (PUFA) have been shown to suppress the inflammatory reactions in vivo and in vitro. PUFA has been shown also to protect against various types of experimental liver damage in animal models and isolated hepatocytes. Therefore, the aim of this study was to investigate the protective effect of PUFA administration on liver damage using the rat chronic biliary obstruction model.

METHODS

Swiss albino rats of either sex were divided into 4 groups as follows: control group (group 1, 10 rats); rats with sham operation and treated with saline group 2, 10 rats); rats with biliary obstruction (group 3, 15 rats); and polyunsaturated phophatidylcholine (PPC)-treated rats with biliary obstruction (Group 4, 15 rats). Biliary obstruction was induced by double ligation and division of the common bile duct. PUFA treatment was started 2 weeks later from biliary obstruction in doses of 50 mg/d per rat and continued for 2 weeks. All animals were killed after 4 weeks of common bile duct ligation or sham operation. Liver damage and cholestasis were determined by biochemical and histologic examinations.

RESULTS

The data showed a decrease in plasma bilirubin level (both conjugated and unconjugated) and liver enzyme levels (AST, ALT, AP, GGT, 5'-NT) in group 4, when compared with group 3 (P <.05). Tissue levels of malondialdehyde (MDA) in group 4 was 20.00 +/- 2.93 compared with that in group 3, 27.12 +/- 2.96 (P <.05). Administration of PUFA to the biliary obstructed rats resulted in inhibition of collagen accumulation (P <.05) and ductal proliferation (P <.05).

CONCLUSIONS

PUFA reduced liver damage, ductular proliferation, and fibrosis in biliary obstructed rats. These effects suggest that it might be a useful agent to preserve liver function in patients with biliary obstruction such as biliary atresia.