Non-cirrhotic Rats Research Articles

Camel milk and bee honey regulate profibrotic cytokine gene transcripts in liver cirrhosis induced by carbon tetrachloride.

The lack of studies regarding the mechanism of the protective effects of camel milk and bee honey against hepatotoxic compounds led us to perform this study. Thirty-six male rats were divided into two main groups. The first group (n = 9) comprised control non-cirrhotic rats. The rats of the second group (n = 27) were administered carbon tetrachloride (CCl4) by intraperitoneal injection to induce liver cirrhosis. The cirrhotic rats were then divided into three equal subgroups, each comprising nine animals, as follows: (i) cirrhotic rats, (ii) cirrhotic rats treated with camel milk, and (iii) cirrhotic rats treated with camel milk and bee honey. The present findings revealed that CCl4 elevated the activities of liver enzymes, blood glucose levels, non-esterified fatty acids (NEFA) in the serum and glycogen content in the liver. On the other hand, CCl4 significantly decreased phosphorylase activity in the liver tissue and significantly increased carbohydrate intolerance and insulin resistance index (HOMA-IR). Moreover, CCl4 induced a significant increase in oxidative stress, along with increased expression of the profibrotic cytokine genes TNF-α and TGF-β. However, camel milk either alone or in combination with bee honey ameliorated these toxic actions. The antioxidant properties of these protective agents and their effects of downregulating certain procirrhotic cytokine gene transcripts underlie this protection.

Statins activate the canonical hedgehog-signaling and aggravate non-cirrhotic portal hypertension, but inhibit the non-canonical hedgehog signaling and cirrhotic portal hypertension

Liver cirrhosis but also portal vein obstruction cause portal hypertension (PHT) and angiogenesis. This study investigated the differences of angiogenesis in cirrhotic and non-cirrhotic PHT with special emphasis on the canonical (Shh/Gli) and non-canonical (Shh/RhoA) hedgehog pathway. Cirrhotic (bile duct ligation/BDL; CCl4 intoxication) and non-cirrhotic (partial portal vein ligation/PPVL) rats received either atorvastatin (15 mg/kg; 7d) or control chow before sacrifice. Invasive hemodynamic measurement and Matrigel implantation assessed angiogenesis in vivo. Angiogenesis in vitro was analysed using migration and tube formation assay. In liver and vessel samples from animals and humans, transcript expression was analyzed using RT-PCR and protein expression using Western blot. Atorvastatin decreased portal pressure, shunt flow and angiogenesis in cirrhosis, whereas atorvastatin increased these parameters in PPVL rats. Non-canonical Hh was upregulated in experimental and human liver cirrhosis and was blunted by atorvastatin. Moreover, atorvastatin blocked the non-canonical Hh-pathway RhoA dependently in activated hepatic steallate cells (HSCs). Interestingly, hepatic and extrahepatic Hh-pathway was enhanced in PPVL rats, which resulted in increased angiogenesis. In summary, statins caused contrary effects in cirrhotic and non-cirrhotic portal hypertension. Atorvastatin inhibited the non-canonical Hh-pathway and angiogenesis in cirrhosis. In portal vein obstruction, statins enhanced the canonical Hh-pathway and aggravated PHT and angiogenesis.

Pioglitazone decreases portosystemic shunting by modulating inflammation and angiogenesis in cirrhotic and non-cirrhotic portal hypertensive rats

Development of the portal-hypertensive syndrome is mediated by splanchnic inflammation and neoangiogenesis. Since peroxisome proliferator-activated receptor gamma (PPARγ) agonists like pioglitazone (PIO) regulate inflammatory response and inhibit angiogenesis in endothelial cells, we evaluated PIO as treatment for experimental portal hypertension. PIO (10 mg/kg) or vehicle (VEH) was administered from day 21-28 after bile duct ligation (BDL), from day 0-7 after partial portal vein ligation (PPVL) or sham-operation (SO), respectively. After treatment, systemic hemodynamics, splanchnic blood flow (SMABF), portal pressure (PP), and portosystemic shunting (PSS) were assessed. Splanchnic and hepatic tissues were analyzed for angiogenic and inflammatory markers. BDL and PPVL showed significantly increased PP, SMABF, and PSS compared to SO-VEH rats. While PIO treatment did not decrease PP or SMABF, PSS was significantly reduced both in cirrhotic (BDL-VEH: 71% to BDL-PIO: 41%; p<0.001) and non-cirrhotic (PPVL-VEH: 62% to PPVL-PIO: 40%; p=0.041) rats. PIO (10 μM, in vitro) inhibited endothelial cell migration and significantly increased PPARγ activity in vivo. In BDL rats, PIO decreased hepatic mRNA levels of PPARγ (p=0.01) and PlGF (p=0.071), and splanchnic mRNA expression of PPARγ (p=0.017), PDGFβ (p=0.053) and TNFα (p=0.075). Accordingly, splanchnic protein expression of PPARγ (p=0.032), VEGFR2 (p=0.035), CD31 (p=0.060) and PDGFβ (p=0.066) were lower in BDL-PIO vs. BDL-VEH animals. In PPVL rats, PIO treatment decreased splanchnic gene expression of Ang2 (-12.4 fold), eNOS (-9.3 fold), PDGF (-7.0 fold), PlGF (-11.9 fold), TGFb (-8.3 fold), VEGF-A (-11.3 fold), VEGFR1 (-5.9 fold), IL1b (-14.4 fold), and IL6 (-9.6 fold). Pioglitazone treatment decreases portosystemic shunting via modulation of splanchnic inflammation and neoangiogenesis. Pioglitazone should be assessed for potential beneficial effects in patients with portosystemic collaterals due to portal hypertension.

Hematologic and hemodynamic effects of splenectomy on cirrhotic and non-cirrhotic portal hypertensive rats

Hematologic and hemodynamic effects of splenectomy on cirrhotic and non-cirrhotic portal hypertensive rats

Terlipressin Resolves Ascites of Cirrhotic Rats through Downregulation of Aquaporin 2

To investigate the presence of aquaporin (AQP) 1 and AQP2 in kidneys of cirrhotic rats with ascites, and to determine the effect of terlipressin on AQP1 and AQP2 levels and its therapeutic efficacy in ascites treatment. Eighteen rats were randomly divided into normal noncirrhotic rats treated with saline, cirrhotic rats treated with saline and cirrhotic rats treated with terlipressin (n = 6 per group). In all rats, 24-h net fluid-excretion volume, presence or absence of ascites and portal vein pressure were measured; AQP1 and AQP2 mRNA and protein levels in renal tissue were evaluated. Terlipressin resolved ascites in all animals in the terlipressin-treated group, and significantly increased the 24-h net fluid-excretion volume and decreased portal vein pressure compared with saline treatment. AQP1 and AQP2 were significantly upregulated in cirrhotic rat kidneys compared with normal control rat kidneys. Terlipressin administration significantly down regulated AQP2 in rat kidneys but did not affect AQP1. AQP1 and AQP2 are important factors in ascites induction. Terlipressin appears to be an effective drug for the treatment of ascites due to liver cirrhosis in a rat model, possibly due to AQP2 reduction in kidneys.

Cholangiocytes of Cirrhotic Rats are More Tolerant to Ischemia than Normal Rats: A Role for Abnormal Hepatic Arteriovenous Communications?

To assess whether cholangiocytes of rats with liver cirrhosis are more tolerant to ischemic changes than normal rats, and whether this is due to arteriovenous fistulas. Ninety-eight Sprague-Dawley rats were divided into the normal group (n = 30) and the cirrhosis group (n = 68), and then each group was divided into controls and those with bile duct ischemia. At 0 h, 6 h, 3 d, and 14 d after the induction of bile duct ischemia, the liver of each rat was removed and stained with toluidine blue to compare cholangiocyte morphology. Cholangiocyteapoptosis was evaluated by a deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labeling (TUNEL) assay. Expression of VEGF, HIF1, NF-kB(p65) was assessed by quantitative analysis of the products of reverse-transcriptase polymerase chain reaction. Resin casts were used to reproduce the intrahepatic vasculature of cirrhotic rats, and the presence of communications between the portal vein and hepatic artery was assessed with stereomicroscopy. Rats with liver cirrhosis were more tolerant than normal rats 6 h after bile duct ischemia (P < 0.05); at 3 and 14 d after the ischemic insult, there was no significant difference between the cirrhotic rats and normal rats. Levels of expression of VEGF, HIF1, and NF-kB(p65) genes, either in normal rats or cirrhotic rats, were significantly elevated compared with those in the control group (∗, ∗∗P < 0.05), but a lower extent changes appeared in the cirrhotic rats (∗∗∗P < 0.05). Several communications could be observed between the portal vein and hepatic artery. Cholangiocytes of cirrhotic rats appear to be more tolerant to ischemia of bile duct than non-cirrhotic rats. This may be due to the protective role of arterioportal fistulas.

Acute effects of endothelin receptor antagonists on hepatic hemodynamics of cirrhotic and noncirrhotic ratsThis article is one of a selection of papers published in the two-part special issue entitled 20 Years of Endothelin Research.

Hepatic and circulating endothelin-1 (ET-1) are increased in patients with cirrhosis and in cirrhotic animals. However, the distinct roles of ET receptor subtypes ETA and ETB in cirrhosis and portal hypertension (PHT) have not been clearly elucidated. Thus, we studied the effects of selective ET-1 antagonists (ETA-ant or ETB-ant) and nonselective ET-1 antagonist (ETA/B-ant) on hepatic hemodynamics in cirrhotic rats. Liver fibrosis and PHT were induced by complete bile duct ligation (BDL) in rats. Two weeks after BDL or sham surgery, hemodynamic responses were measured during intraportal infusion of incremental doses of the following ET-ants: (i) BQ-123, (ii) BQ-788, and (iii) bosentan. After equilibration with vehicle, doses of ET-ants were infused for 30 min periods, and steady-state systemic and hepatic hemodynamics, portal venous pressure (PVP), and hepatic blood flow (HBF) were measured. BDL induced significant PHT and elevated concentrations of plasma ET-1 compared with sham. ETA-ant decreased PVP of cirrhotic rats but had no effect on sham, whereas ETB-ant increased PVP in sham but had no effect in BDL. Nonselective ETA/B-ant decreased PVP of BDL similarly to ETA-ant. Both ETA-ant and ETB-ant decreased local HBF, whereas a nonselective antagonist did not change HBF in sham; however no significant changes were observed in HBF of BDL rats with any of the antagonists. These findings suggest ETA activation contributes to PHT in cirrhotic rats, whereas ETB-mediated portal depressor effects are attenuated in cirrhotic rats compared with noncirrhotic rats.

Vascular hyporesponsiveness to angiotensin II in rats with CCl4‐induced liver cirrhosis

Portal hypertension is triggered by vasodilation due to impaired contraction of extrahepatic vessels. Angiotensin II type 1 (AT(1)) receptor-induced vasocontraction is mediated by G proteins and may be desensitized by recruitment of beta-arrestin-2 to the receptor. In this study, we analysed the interaction of AT(1) receptors with beta-arrestin-2 in the context of vascular hypocontractility in rats with CCl(4)-induced cirrhosis. Micronodular liver cirrhosis in rats (n = 15) was induced by regular CCl(4) exposure. Age-matched rats (n = 15) served as controls. Contractility of aortic rings was measured by myography. Protein expressions and phosphorylations were assessed by Western blot analysis, and AT(1) receptor interaction with beta-arrestin-2 by co-immunoprecipitation. Aortic rings from CCl(4) rats were hypocontractile to angiotensin II independent of nitric oxide synthases (Nomega-nitro-l-arginine methyl ester 200 microM). Expression of the AT(1) receptor, Galpha(q/11) and the contraction-mediating effector Rho kinase was similar in aortas from both groups. Expression and AT(1) receptor binding of beta-arrestin-2 were up-regulated in aortas from CCl(4) rats. Stimulation of isolated aortas with exogenous angiotensin II caused recruitment of beta-arrestin-2 in aortas from noncirrhotic rats, but no further interaction of AT(1) receptors with beta-arrestin-2 was found in aortas from CCl(4) rats. While angiotensin II stimulation resulted in Rho kinase activation in aortas from noncirrhotic rats but not in aortas from CCl(4) rats, extracellular signal-regulated kinase activation in response to angiotensin II was observed in aortas from both groups. Vascular hyporesponsiveness to angiotensin II in CCl(4) rats is due to enhanced interaction of the AT(1) receptor with beta-arrestin-2 and consecutively changed receptor function.

Sorafenib attenuates the portal hypertensive syndrome in partial portal vein ligated rats

Angiogenesis plays a key role in development of portal hypertension (PHT) and represents a potential therapeutic target. We aimed to evaluate the molecular effects of sorafenib, a multiple tyrosine kinase inhibitor, on splanchnic hemodynamics in rats with partial portal vein ligation (PPVL). The following four groups of rats were treated orally with sorafenib (10mg/kg per day; SORA group) or placebo (PLAC group) for 7 days, beginning at the day of PPVL or sham operation (SO): (1) PPVL-SORA, (2) PPVL-PLAC, (3) SO-SORA and (4) SO-PLAC. Measurements of mean arterial pressure (MAP), portal pressure (PP), and superior mesenterial artery blood flow (SMABF) were performed. Portosystemic collateral blood flow (PSCBF) was determined by radioactive microspheres. Splanchnic protein expression of CD31, alpha-smooth muscle actin (alphaSMA), phospho-extracellular signal-regulated kinase (pERK), vascular endothelial growth factor (VEGF), platelet-derived growth factor (PDGF), tumor necrosis factor alpha (TNFalpha), and endothelial nitric oxide synthetase (eNOS) was assessed by Western blot. Gene expression was studied by angiogenesis-focused real-time reverse transcription polymerase chain reaction microarray. PP, SMABF, and PSCBF were significantly higher in PPVL rats than in SO rats. MAP and heart rate were similar in all groups. Treatment with sorafenib resulted in a significant decrease of PP (p<0.001) and SMABF (p<0.05) in PPVL-SORA rats compared to PPVL-PLAC rats. PPVL-SORA rats had markedly less PSCBF than PPVL-PLAC rats (p<0.001). Superior mesenteric artery resistance (SMAR) was significantly lower in both PPVL groups compared to both SO groups, but PPVL-SORA rats showed significantly higher SMAR than PPVL-PLAC rats (p<0.05). The increased protein expression of CD31, alphaSMA, pERK, VEGF, PDGF, TNFalpha, and eNOS in rats with PHT was markedly decreased by sorafenib treatment. Sorafenib decreased mRNA levels of TNFalpha, VEGF receptor 2, VEGF receptor 1, transforming growth factor beta, cyclooxygenase 1, and expression of various genes that are involved in pathways of cellular proliferation, fibrogenesis, tissue remodeling, inflammation, and angiogenesis. Treatment with sorafenib reduced PP, SMABF, and PSCBF in noncirrhotic rats with prehepatic PHT, without affecting systemic hemodynamics. Additional antiproliferative, anti-inflammatory, and antiangiogenic effects of sorafenib were identified.

Improved hepatocyte function of future liver remnant of cirrhotic rats after portal vein ligation: A bonus other than volume shifting

Preoperative portal vein embolization is increasingly employed for those with hepatocellular carcinoma and cirrhosis to gain a volume-shifting effect. However, the alterations of histologic architecture and hepatocyte function of future liver remnant (FLR) remain unexplored. Portal vein ligation (PVL) was performed in cirrhotic and noncirrhotic rats. Regeneration indices that include the DNA synthesis index, restituted liver mass, and the redistributed volume ratio were measured. The indocyanine green 15' retention test (ICG-R15), histologic changes, total Knodell score, and activated hepatic stellate cells (HSCs) were measured before and after PVL. Tc-99m sulfur-colloid liver single photon emission computed tomography (SPECT) and diisopropyl iminoacetic acid (DISIDA) SPECT were conducted. The redistributed volume ratio of cirrhotic rats was less than noncirrhotic rats (63% vs 80%, P < .01). The ICG-R15 of cirrhotic rats at day 7 after PVL was improved compared with baseline (6.0 +/- 4.1% vs 15.8 +/- 4.6%, P < .01). The total Knodell score and activated HSCs of FLR in cirrhotic rats both were decreased compared with those of baseline. The redistributed volume ratio of noncirrhotic and cirrhotic rats based on 99mTc sulfur-colloid SPECT were 79% and 64%, respectively. The clearance T(1/2) of FLR in cirrhotic rats based on DISIDA SPECT was decreased compared with baseline (5.2 +/- 1.9 min vs 8.6 +/- 3.1 min). The regenerated functional liver mass of cirrhotic rats after PVL is less than noncirrhotic rats, whereas the hepatocyte function of FLR in cirrhotic rats is improved relevant to tissue remodeling.

Evaluation of the protective effects of quercetin in the hepatopulmonary syndrome

The hepatopulmonary syndrome (HPS) occurs when intrapulmonary dilatation causes hypoxemia in cirrhosis. The free radicals may play a significant contributory role in the progression of HPS, and flavonoid agents could protect against deleterious effects of free radicals. The flavonoid quercetin was evaluated in an experimental model of biliary cirrhosis induced by bile duct ligation (BDL) in rats. Quercetin was administered at 50 mg/kg for 14 days to cirrhotic and non-cirrhotic rats. Bone marrow was extracted from animals to analyze micronuclei. Lung, liver and blood were extracted to detect DNA damage using the comet assay. The results showed that the micronuclei and DNA damages to lung and liver were increased in BDL rats. Quercetin caused no damage to the DNA while decreasing the occurrence of micronucleated cells in bone marrow as well as DNA damage to lung and liver in cirrhotic rats. Quercetin showed antimutagenic activity against hydroperoxides as evaluated by the oxidative stress sensitive bacterial strains TA102 Salmonella typhimurium and IC203 Escherichia coli, suggesting protection by free radical scavenging. In Saccharomyces cerevisie yeast strains lacking mitochondrial or cytosolic superoxide dismutase, these results indicate that quercetin protects cells by induction of antioxidant enzymes. The present study is the first report of genotoxic/antigenotoxic effects of quercetin in a model of animal cirrhosis. In this model, quercetin was not able to induce genotoxicity and, conversely, it increased the genomic stability in the cirrhotic rats, suggesting beneficial effects, probably by its antioxidant properties.

Effects of a selective beta 2-blocker (ICI 118,551) on hepatic haemodynamics in the cirrhotic and non-cirrhotic rat.

The effects of a selective beta 2-blocker (ICI 118,551) on hepatic haemodynamics were studied in cirrhotic and non-cirrhotic rats. Infusions of 10 and 20 microgram (kg body wt)-1 min-1 beta 2-blocker (in cirrhotic and non-cirrhotic rats) significantly reduced portal pressure, portal venous flow and liver blood flow without altering heart rate. Splanchnic vascular resistance was significantly increased following infusions of 10 and 20 micrograms (kg body wt)-1 min-1 beta 2-blocker. An intraportal injection of beta 2-blocker (10 micrograms body wt)-1 or hepatic artery ligation lowered portal pressure by approximately the same magnitude. Intraportal injection of beta 2-blocker after hepatic artery ligation did not further reduce portal pressure. The results indicate that a selective beta 2-blocker reduces portal pressure by a combination of increased splanchnic vascular resistance and hepatic arterial resistance. It is concluded that a selective beta 2-blocker may be of clinical value in the long-term managements of portal hypertension.

Effects of propranolol on hepatic haemodynamics in the cirrhotic and non-cirrhotic rat.

The effects of systemic and intraportal administration of propranolol on hepatic haemodynamics were studied in cirrhotic and non-cirrhotic rats. In the non-cirrhotic rat systemic infusion of 4 micrograms (kg body wt)-1 min-1 propranolol significantly decreased portal pressure, wedged hepatic venous pressure, portal venous flow and liver blood flow without affecting heart rate. Similar changes were observed in the cirrhotic rat following an infusion of 2 micrograms (kg body wt)-1 min-1 propranolol. Higher rates of propranolol infusion produced greater reductions in portal pressure, wedged hepatic venous pressure, portal venous flow and liver blood flow in cirrhotic and non-cirrhotic rats but these changes were accompanied by a bradycardia. The reduction in portal pressure effected by propranolol was accompanied by an increased splanchnic vascular resistance. Intraportal injection of propranolol resulted in a rapid but transient fall in portal pressure. The decrease in portal pressure was sustained if propranolol was infused intraportally. The results indicate that propranolol effects a reduction in portal pressure via a combination of increased splanchnic vascular resistance, increased hepatic arterial resistance and reduced cardiac output. The observation that propranolol can significantly reduce portal pressure without affecting heart rate may be clinically important in the long-term management of portal hypertension. Furthermore, the rapid reduction in portal pressure following intravenous administration suggests that propranolol may be of value in the acute control of variceal haemorrhage.

Beneficial Effect of Hyperbaric Oxygenation on Liver Regeneration in Cirrhosis

Underlying hepatic injury and cirrhosis are leading factors that interfere with the post-operative liver regeneration and function. Hyperbaric oxygenation (HBO) has been reported to ameliorate the ischemia-reperfusion injury of the liver, to induce compensatory hypertrophy of the predicted remnant liver in rats after portal vein ligation and to augment liver regeneration after hepatectomy in non-cirrhotic rats. Our aim was to determine the effect of HBO treatment on liver regeneration after partial hepatectomy in normal and cirrhotic mice in this experimental study. The effect of HBO on liver regeneration was studied in a mice model combining carbon tetrachloride induced cirrhosis and partial hepatectomy. Mice were divided into four groups: Control, cirrhotic, non-cirrhotic HBO-treated, and cirrhotic HBO-treated. All animals underwent 40% hepatectomy. Liver regeneration was evaluated by the proliferating cell nuclear antigen-labeling index. Serum aspartate aminotransferase and alanine aminotransferase levels were measured to evaluate liver injury. Serum alanine aminotransferase and aspartate aminotransferase levels were significantly decreased in HBO-treated cirrhotic group compared to cirrhosis group after hepatectomy (P = 0.001 and P = 0.014, respectively). The proliferating cell nuclear antigen labeling index was significantly higher in HBO treated cirrhotic group than in cirrhotic group after hepatectomy (P = 0.022). Our results suggest that HBO treatment improves liver functions and augments hepatocyte regeneration in cirrhotic mice after hepatectomy. Post-operative HBO treatment may have a beneficial effect on post-operative liver function and regeneration in cirrhotic patients.

Effects of vasopressin on portal-systemic collaterals of cirrhotic rats

ObjectiveArginine vasopressin (AVP) exerts a constrictive effect on the portal-systemic collaterals of non-cirrhotic portal hypertensive rats, but its effect on cirrhotic rats is unknown. The aim of this study was to investigate the response of AVP and the modulatory roles of nitric oxide and prostaglandin on collaterals of common bile duct-ligated (BDL) cirrhotic rats.Material and methodsThe collateral vascular responsiveness to graded concentrations of AVP (10−10–3×10−7 M) was tested by an in situ collateral perfusion system pretreated with Nω-nitro-L-arginine (L-NNA, 100 μM), indomethacin (INDO, 10 μM), or both. The collateral responses to AVP with the pretreatment of a vasopressin V1 receptor antagonist d(CH2)5Tyr(Me) arginine vasopressin or a V2 receptor agonist 1-desamino-8-D-arginine vasopressin (DDAVP, 10−10–3×10−7 M) were also evaluated.ResultsThe perfusion pressure of collaterals was significantly increased by AVP, and this effect was inhibited by the addition of the V1 receptor antagonist. DDAVP had no effect on the collaterals. Incubation with L-NNA or L-NNA plus INDO, but not INDO alone, significantly potentiated the constrictive effects of AVP. The constrictive effect of AVP in the combination group was similar to that in the L-NNA alone group.ConclusionsThe results show that AVP produces a direct vasoconstrictive effect on the portal-systemic collaterals of BDL cirrhotic rats. The constrictive effect of AVP is mediated by the vasopressin V1, instead of V2, receptors. Nitric oxide may play a more important role than prostaglandin in modulating the collateral vascular response to AVP in BDL cirrhotic rats.

Impact of endothelin-1 on microcirculatory disturbance after partial hepatectomy under ischemia/reperfusion in thioacetamide-induced cirrhotic rats

Background. Endothelin (ET)-1 contributes to hepatic ischemia and reperfusion (HIR) injury in normal liver. This study was conducted to clarify the role of ET-1 in HIR injury in cirrhotic state. Materials and Methods. Using thioacetamide-induced cirrhotic rats with spontaneous portosystemic shunt, we determined the changes in plasma aspartate aminotransferase (AST) levels, plasma and hepatic ET-1 values, 7-day survival rates, and hepatic oxygen saturation (SO 2) by time-resolved spectroscopy as an indicator of hepatic microcirculation under intermittent or continuous total hepatic ischemia with subsequent partial hepatectomy. Results. Hepatic ET-1 levels in cirrhotic rats were significantly higher than those in noncirrhotic rats. Plasma and hepatic ET-1 levels at 1, 3 and 6 h of reperfusion after intermittent hepatic ischemia were significantly lower than those after continuous hepatic ischemia. In cirrhotic animals subjected to intermittent hepatic ischemia, the elevation of plasma AST levels at 1, 3 and 6 h of reperfusion and the decline in hepatic SO 2 at the end of 60-min hepatic ischemia and after reperfusion were significantly suppressed when compared with those subjected to continuous hepatic ischemia. Pretreatment with a nonselective endothelin receptor antagonist in continuous hepatic ischemia significantly ameliorated plasma AST levels and hepatic SO 2 values with less hepatic sinusoidal congestion, resulting in an improvement in the 7-day survival rate. Conclusions. Continuous hepatic ischemia in the cirrhotic liver has disadvantages relating to microcirculatory derangement with more ET-1 production in partial hepatectomy. In liver surgery, pharmacological regulation of ET-1 production may lead to attenuation of reperfusion injuries for ischemically damaged cirrhotic liver.

Role of endothelin-1 in a cirrhotic rat model with endotoxin induced acute renal failure

Background/aims: Bacterial infections are known to trigger renal failure in patients with cirrhosis. However, the mechanisms for this process are unclear. The aim of this study was to investigate the role of endothelin-1 (ET-1) in a cirrhotic rat model with endotoxin induced renal failure by mixed ET-1 receptor antagonist, bosentan. Methods: Cirrrhosis was induced by twice weekly intraperitoneal injections of CCl 4 together with phenobarbital in drinking water. Cirrhotic and non-cirrhotic rats were either pretreated with physiological saline or bosentan prior to administration of low dose endotoxin. Urine and blood samples were then collected within a period of 3 h for the estimation of ET-1, NO 3 −/NO 2 − levels ( nitric oxide metabolites: NO x ) and renal function tests. Results: Cirrhotic rats had higher ET-1 and NO x levels in comparison with non-cirrhotic rats. Endotoxin administration to cirrhotic rats led to the deterioration of the renal function, and elevation of plasma ET-1 and NO x levels. Bosentan pretreatment prior to endotoxin administration caused an increase in the urine volume and creatinine clearance of cirrhotic rats, but had no effect on Na + excretion. Conclusion: ET-1 has a significant role in endotoxin induced renal impairment in cirrhotic rats, and ET-1 receptor antagonism provides partial protection of the renal function.

Effect of Lactobacillus johnsonii La1 and antioxidants on intestinal flora and bacterial translocation in rats with experimental cirrhosis

Background/Aims: Probiotics and antioxidants could be alternatives to antibiotics in the prevention of bacterial infections in cirrhosis. The aim of the present study was to determine the effect of Lactobacillus johnsonii La1 and antioxidants on intestinal flora, endotoxemia, and bacterial translocation in cirrhotic rats. Methods: Twenty-nine Sprague–Dawley rats with cirrhosis induced by CCl 4 and ascites received Lactobacillus johnsonii La1 10 9 cfu/day in vehicle (antioxidants: vitamin C+glutamate) ( n=10), vehicle alone ( n=11), or water ( n=8) by gavage. Another eight non-cirrhotic rats formed the control group. After 10 days of treatment, a laparotomy was performed to determine microbiological study of ileal and cecal feces, bacterial translocation, endotoxemia, and intestinal malondialdehyde (MDA) levels as index of intestinal oxidative damage. Results: Intestinal enterobacteria and enterococci, bacterial translocation (0/11 and 0/10 vs. 5/8, P<0.01), and ileal MDA levels ( P<0.01) were lower in cirrhotic rats treated with antioxidants alone or in combination with Lactobacillus johnsonii La1 compared to cirrhotic rats receiving water. Only rats treated with antioxidants and Lactobacillus johnsonii La1 showed a decrease in endotoxemia with respect to cirrhotic rats receiving water ( P<0.05). Conclusions: Antioxidants alone or in combination with Lactobacillus johnsonii La1 can be useful in preventing bacterial translocation in cirrhosis.

Differential effect of CCl 4 on renal function in cirrhotic and non-cirrhotic rats

The pathogenesis of renal function alteration associated with liver disease remains to be elucidated. Although different experimental animal models have been utilized in order to explain such pathophysiological state, none of them have completely explained the mechanisms involved. In this study we performed differential hemodynamic, hepatic and renal function alteration studies after induction of acute liver damage via intragastric administration of a single dose of CCl4 to cirrhotic and non-cirrhotic rats. Cirrhotic rats with acute liver damage exhibited a significant decrease in mean arterial pressure followed by a decreased glomerular filtration rate, urinary sodium concentration and an induction of plasma renin concentration and activity. At the same time, a significant association between oliguria and mortality was observed. The renal histopathological studies revealed glomeruli with mesangial hypercellularity and thickening of capillary wall, but not tubular epithelial injury. All these alterations were not detected in the control group, i.e. by non-cirrhotic rats with acute liver damage. This study suggests that the effect of CCl4 on kidney structure and function depends on the functional state of the liver. Since this experimental model of acute liver damage in cirrhotic rats presents hemodynamics and renal function alterations similar to those observed in the hepatorenal syndrome in man, it could be utilized to study the pathogenesis of renal function alterations associated with liver damage.

Effect of serum from partially hepatectomized cirrhotic and noncirrhotic rats on liver regeneration with primary hepatocyte cultures.

The effects of serum from cirrhotic and noncirrhotic rats after 33% and 70% partial hepatectomy on the hepatocyte culture were studied. Liver cirrhosis was produced by weekly intragastric feeding with carbon tetrachloride (CCl4) for 12-16 weeks. The serum was prepared with blood withdrawn from the rats 2 and 48 h after partial hepatectomy or sham operation. The incorporation of [3H]thymidine in the hepatocyte culture after addition of rat serum (1.0 +/- 10(5) cells/ml) was assessed. We found that the mitogenic effect of the serum at 2 and 48 h after partial hepatectomy was not significant. In the 70% hepatectomy group, the serum from cirrhotic rats had a stronger stimulatory effect to induce hepatocytes in primary culture entering DNA synthesis than that from noncirrhotic rats; but the difference was not statistically significant. The mitogenic effect of the serum from noncirrhotic rats after 33% hepatectomy was significantly lower than that from cirrhotic rats after 33% hepatectomy (p < 0.05). In this series, the serum from the cirrhotic rats after 33% hepatectomy had the strongest mitogenic effect; the serum from the partially hepatectomized rats with cirrhotic and non-cirrhotic livers increased [3H]thymidine uptake into hepatocyte DNA significantly more than control serum or plasma.