Ammonia reduction with ornithine phenylacetate restores brain eNOS activity via the DDAH-ADMA pathway in bile duct-ligated cirrhotic rats

2012 ◽  
Vol 302 (1) ◽  
pp. G145-G152 ◽  
Author(s):  
Vairappan Balasubramaniyan ◽  
Gavin Wright ◽  
Vikram Sharma ◽  
Nathan A. Davies ◽  
Yalda Sharifi ◽  
...  
Keyword(s):  
Bile Duct ◽  
Protein Expression ◽  
Ammonia Concentration ◽  
Sham Operation ◽  
Sprague Dawley ◽  
Sprague Dawley Rats ◽  
Duct Ligation ◽  
Tnf Α ◽  
No Signaling ◽  
Brain Water

Ammonia is central in the pathogenesis of hepatic encephalopathy, which is associated with dysfunction of the nitric oxide (NO) signaling pathway. Ornithine phenylacetate (OP) reduces hyperammonemia and brain water in cirrhotic animals. This study aimed to determine whether endothelial NO synthase activity is altered in the brain of cirrhotic animals, whether this is associated with changes in the endogenous inhibitor, asymmetric-dimethylarginine (ADMA) and its regulating enzyme, dimethylarginine-dimethylaminohydrolase (DDAH-1), and whether these abnormalities are restored by ammonia reduction using OP. Sprague-Dawley rats were studied 4-wk after bile duct ligation (BDL) ( n = 16) or sham operation ( n = 8) and treated with placebo or OP (0.6 g/kg). Arterial ammonia, brain water, TNF-α, plasma, and brain ADMA were measured using standard techniques. NOS activity was measured radiometrically, and protein expression for NOS enzymes, ADMA, DDAH-1, 4-hydroxynonenol (4HNE), and NADPH oxidase (NOX)-1 were measured by Western blotting. BDL significantly increased arterial ammonia ( P < 0.0001), brain water ( P < 0.05), and brain TNF-α ( P < 0.01). These were reduced significantly by OP treatment. The estimated eNOS component of constitutive NOS activity was significantly lower ( P < 0.05) in BDL rat, and this was significantly attenuated in OP-treated animals. Brain ADMA levels were significantly higher and brain DDAH-1 significantly lower in BDL compared with sham ( P < 0.01) and restored toward normal following treatment with OP. Brain 4HNE and NOX-1 protein expression were significantly increased in BDL rat brain, which were significantly decreased following OP administration. We show a marked abnormality of NO regulation in cirrhotic rat brains, which can be restored by reduction in ammonia concentration using OP.

CXCR2 is involved in pulmonary intravascular macrophage accumulation and angiogenesis in a rat model of hepatopulmonary syndrome

2016 ◽  
Vol 131 (2) ◽  
pp. 159-168 ◽  
Author(s):  
Xujiong Li ◽  
Yunxia Chen ◽  
Yongli Chang ◽  
Shufen Li ◽  
Zhongfu Zhao ◽  
...  
Keyword(s):  
Normal Saline ◽  
Venous Pressure ◽  
Hepatopulmonary Syndrome ◽  
Sham Operation ◽  
Sprague Dawley ◽  
Common Bile Duct Ligation ◽  
Pulmonary Tissue ◽  
Post Surgery ◽  
Duct Ligation ◽  
Tnf Α

Hepatopulmonary syndrome (HPS) is a lung complication in various liver diseases, with high incidence, poor prognosis and no effective non-surgical treatments in patients with hepatocirrhosis. Therefore, assessing HPS pathogenesis to explore proper therapy strategies is clinically relevant. In the present study, male Sprague–Dawley rats underwent sham operation or common bile duct ligation (CBDL). Two weeks post-surgery, the following groups were set up for 2 weeks of treatment: sham + normal saline, CBDL + CXCR2 antagonist SB225002, CBDL + tumour necrosis factor α (TNF-α) antagonist PTX and CBDL + normal saline groups. Liver and lung tissues were collected after mean arterial pressure (MAP) and portal venous pressure (PVP) measurements. Haematoxylin and eosin (H&E) staining (lung) and Masson staining (liver) were performed for pathological analyses. Finally, pulmonary tissue RNA and total protein were assessed for target effectors. The mRNA and protein levels of CXCR2 were significantly increased in the pulmonary tissue of CBDL rats. What's more, CXCR2 inhibition by SB225002 reduced the expression of CD68 and von Willebrand factor (vWf) in CBDL rats. Importantly, CXCR2 inhibition suppressed the activation of Akt and extracellular signal-regulated kinase (ERK) in CBDL rats. Antagonization of TNF-α with PTX down-regulated the expression of CXCR2. During HPS pathogenesis in rats, CXCR2 might be involved in the accumulation of pulmonary intravascular macrophages and angiogenesis, possibly by activating Akt and ERK, with additional regulation by TNF-α that enhanced pulmonary angiogenesis by directly acting on the pulmonary tissue. Finally, the present study may provide novel targets for the treatment of HPS.

Role of thromboxane A2 in early BDL-induced portal hypertension

2003 ◽  
Vol 284 (3) ◽  
pp. G453-G460 ◽  
Author(s):  
Yukihiro Yokoyama ◽  
Hongzhi Xu ◽  
Nicole Kresge ◽  
Steve Keller ◽  
Amir H. Sarmadi ◽  
...  
Keyword(s):  
Portal Hypertension ◽  
Portal Pressure ◽  
Sham Operation ◽  
Sprague Dawley ◽  
Bicarbonate Buffer ◽  
Constant Flow Rate ◽  
Sprague Dawley Rats ◽  
Duct Ligation ◽  
Cox 2

Although the mechanisms of cirrhosis-induced portal hypertension have been studied extensively, the role of thromboxane A2 (TXA2) in the development of portal hypertension has never been explicitly explored. In the present study, we sought to determine the role of TXA2 in bile duct ligation (BDL)-induced portal hypertension in Sprague-Dawley rats. After 1 wk of BDL or sham operation, the liver was isolated and perfused with Krebs-Henseleit bicarbonate buffer at a constant flow rate. After 30 min of nonrecirculating perfusion, the buffer was recirculated in a total volume of 100 ml. The perfusate was sampled for the enzyme immunoassay of thromboxane B2(TXB2), the stable metabolite of TXA2. Although recirculation of the buffer caused no significant change in sham-operated rats, it resulted in a marked increase in portal pressure in BDL rats. The increase in portal pressure was found concomitantly with a significant increase of TXB2 in the perfusate (sham vs. BDL after 30 min of recirculating perfusion: 1,420 ± 803 vs. 10,210 ± 2,950 pg/ml; P < 0.05). Perfusion with a buffer containing indomethacin or gadolinium chloride for inhibition of cyclooxygenase (COX) or Kupffer cells, respectively, substantially blocked the recirculation-induced increases in both portal pressure and TXB2 release in BDL group. Hepatic detection of COX gene expression by RT-PCR revealed that COX-2 but not COX-1 was upregulated following BDL, and this upregulation was confirmed at the protein level by Western blot analysis. In conclusion, these results clearly demonstrate that increased hepatic TXA2 release into the portal circulation contributes to the increased portal resistance in BDL-induced liver injury, suggesting a role of TXA2 in liver fibrosis-induced portal hypertension. Furthermore, the Kupffer cell is likely the source of increased TXA2, which is associated with upregulation of the COX-2 enzyme.

Role of heme oxygenase-carbon monoxide pathway in pathogenesis of cirrhotic cardiomyopathy in the rat

2001 ◽  
Vol 280 (1) ◽  
pp. G68-G74 ◽  
Author(s):  
Hongqun Liu ◽  
Daisheng Song ◽  
Samuel S. Lee
Keyword(s):  
Bile Duct ◽  
Protein Expression ◽  
Heme Oxygenase ◽  
Papillary Muscle ◽  
Cardiac Contraction ◽  
Zinc Protoporphyrin ◽  
Sham Operation ◽  
Muscle Contractility ◽  
Cirrhotic Cardiomyopathy ◽  
Duct Ligation

The enzyme heme oxygenase (HO), which exists in inducible (HO-1) and constitutive (HO-2) isoforms, degrades heme to biliverdin and CO. CO depresses cardiac contraction via cGMP. We aimed to clarify a possible role for the HO-CO pathway in the pathogenesis of cirrhotic cardiomyopathy in bile duct-ligated rats. Four weeks after bile duct ligation or sham operation, rat ventricles were examined for HO-1 and HO-2 mRNA by RT-PCR and for protein expression by Western blotting. Total HO enzyme activity and cGMP levels were also measured. The effects of a HO inhibitor, zinc protoporphyrin IX (ZnPP), on ventricular cGMP levels and isolated papillary muscle contractility were studied. We found that HO-1 mRNA transcription and protein expression were significantly augmented in cirrhotic hearts compared with sham-operated controls, whereas there was no difference in HO-2 mRNA or protein levels. Total HO activity and cGMP levels were significantly increased in cirrhotic ventricles vs. controls. In cirrhotic ventricles, treatment with ZnPP significantly decreased cGMP production and improved the blunted papillary muscle contractility, whereas it had no effect on control muscles. CO perfusion inhibited papillary muscle contractility, an effect completely blocked by methylene blue and partially blocked by ZnPP. These results indicate that activation of the HO-CO-cGMP pathway is involved in the pathogenesis of cirrhotic cardiomyopathy.

Attenuated febrile response to lipopolysaccharide in rats with biliary obstruction

2000 ◽  
Vol 279 (1) ◽  
pp. G172-G177 ◽  
Author(s):  
L. K. McCullough ◽  
Y. Takahashi ◽  
T. Le ◽  
Q. J. Pittman ◽  
M. G. Swain
Keyword(s):  
Serum Levels ◽  
Sham Operation ◽  
Sprague Dawley ◽  
Febrile Response ◽  
Perioperative Morbidity ◽  
Sprague Dawley Rats ◽  
Tnf Α ◽  
Factor Α ◽  
Generation Male ◽  
Necrosis Factor

Patients with biliary tract obstruction have unexplained, inordinately high rates of perioperative morbidity and mortality, whereas cholestatic animals display abnormal hypothalamic responses to pyrogenic stimuli. We asked if obstructive cholestasis was associated with abnormal fever generation. Male Sprague-Dawley rats (250 g) underwent laparotomy for implantation of thermistors and either bile duct resection (BDR) or sham operation. After recovery, temperatures were recorded by telemetry and conscious, unrestrained rats in each group were injected intraperitoneally with either interleukin-1β (IL-1β;1 μg/kg) or Escherichia colilipopolysaccharide (LPS; 50 μg/kg). Baseline temperatures in both groups were similar. Febrile responses after IL-1β injection in BDR and sham groups were not significantly different. However, in response to LPS injection, BDR rats showed an initial hypothermia with a subsequently attenuated febrile response. Administration of anti-tumor necrosis factor-α (TNF-α) antibody 2 h before LPS injection blocked the LPS-induced hypothermia seen in BDR animals. However, serum levels of TNF-α were not significantly different between sham and BDR animals after LPS injection at any time point measured (0, 1.5, and 3 h).

Partial Ligation of the Common Bile Duct Results in Reversible Cholestasis in Rats

2016 ◽  
Vol 101 (5-6) ◽  
pp. 249-256 ◽  
Author(s):  
Jun Jiang ◽  
Dongzheng Li ◽  
Jishu Wei ◽  
Kuirong Jiang ◽  
Yi Miao
Keyword(s):  
Bile Duct ◽  
Common Bile Duct ◽  
Bile Salt ◽  
Bile Duct Ligation ◽  
Serum Biochemistry ◽  
Sham Operation ◽  
Sprague Dawley ◽  
Common Bile Duct Ligation ◽  
Ductular Reaction ◽  
Duct Ligation

The animal model of common bile duct ligation is very toxic; therefore, the aim of this study was to establish a new model of obstructive jaundice in rats with partial common bile duct obstruction. Male Sprague-Dawley rats were subjected to a sham operation or partial ligation of bile duct procedure. Serum biochemistry, liver histology, and expression of bile salt transporters were examined after surgery. Serum levels of aspartate aminotransferase, alkaline phosphatase, total bilirubin, and bile acids were significantly increased in the partial bile duct ligation group 3 days after surgery. However, these changes spontaneously normalized within 14 days after surgery in the partial bile duct ligation group compared with the sham group. Bile infarcts, ductular reaction, and abundant hepatocyte turnover were detected exclusively in the partial bile duct ligation group on postoperative day 3. However, these changes dramatically reversed 14 days after surgery. Bile salt transporter expression was significantly decreased at day 3 and gradually recovered in the following 2 weeks. In conclusion, the current rat model of obstructive cholestasis is reversible, representing the clinical characteristics of partial biliary obstruction, and may be used to investigate the effects of various therapeutic strategies on reversible acute cholestasis.

A new method for the experimental induction of secundary biliary cirrhosis in wistar rats

2001 ◽  
Vol 16 (2) ◽  
pp. 75-81 ◽  
Author(s):  
Gracinda De Lourdes Jorge ◽  
Luiz Sergio Leonardi ◽  
Ilka de Fatima Santana Ferreira Boin ◽  
Orlando de Castro e Silva Jr ◽  
Cecilia Amelia Fazzio Escanhoela
Keyword(s):  
Bile Duct ◽  
Morphological Study ◽  
Wistar Rats ◽  
Hepatic Duct ◽  
Control Group ◽  
Sham Operation ◽  
Biliary Cirrhosis ◽  
Technical Failure ◽  
Duct Obstruction ◽  
Duct Ligation

The aim of this study was to describe a method for the induction of experimental secondary biliary fibrosis (SBF). Forty-seven Wistar rats were submitted to hepatic duct obstruction (OB group) for thirty days without ligature, section or cannulization causing interruption of biliary flow. This technique was carried out by simple traction of the bile duct passing it through the xiphoid appendix. Nine rats were submitted to a sham operation for bile duct stricture and seven rats comprised the control group. Blood samples were collected for the measurement of total bilirubin (TB), alkaline phosphatase (AP), alanine aminotransferase (ALT) and aspartate aminotransferase (AST). Liver fragments were removed for morphological study. Thirty days after surgery TB, AP, ALT and AST levels were significantly increased in the hepatic duct ligation group compared to the sham operated group and the presence of SBF in the OB group was confirmed by morphological study of the liver. There was technical failure in 31.92% cases. The survival was 100% at fifteen days and 82.97% at the end of the experiment. We concluded that this simple surgical technique may be used to study the consequence of bile duct obstruction which could be a reversible process depending on the obstruction time. This technique can be carried out from cholestasis to fibrosis.

scholarly journals Liver histological, portal flow and plasmatic nitric oxide alterations caused by biliary obstruction and drainage in rats

2008 ◽  
Vol 23 (suppl 1) ◽  
pp. 2-7 ◽  
Author(s):  
Miguel Angel Dias ◽  
Reginaldo Ceneviva ◽  
Jorge Elias Jr. ◽  
Sergio Zucoloto ◽  
Caroline Floreoto Baldo ◽  
...  
Keyword(s):  
Bile Duct ◽  
Biliary Obstruction ◽  
Bile Duct Ligation ◽  
Sham Operation ◽  
Portal Flow ◽  
Histological Alterations ◽  
Duct Occlusion ◽  
Duct Ligation ◽  
Male Wistar Rats ◽  
Periodic Evaluation

PURPOSE: To evaluate liver alterations caused by biliary obstruction and drainage. METHODS: Thirty-nine male Wistar rats were randomly distributed in 4 groups: BO (n=18) bile duct ligation for 20 days, with a periodic evaluation of liver histological alterations, Doppler echography portal flow and measurements of NO and malondialdehyde (MDA); BO/DB (n=13) bile duct occlusion for 20 days followed by biliary drainage by choledochoduodenal anastomosis, 5 days follow-up, same BO group parameters evaluations; group CED (n=4) sham operation and portal flow evaluation trough 20 days; CHB (n=4) sham operation, with hepatic biopsy on 25th day and followed-up trough 25 days, by the same parameters of group BO, with exception of portal flow. Direct bilirubin (DB) and alkaline phosphatase (AP) were evaluated in the group BO, BO/DB and CHB. RESULTS: The bile duct ligation led to an increase of DB and AP, development of liver histological alterations, reduction of portal flow and increase of plasmatic NO and of MDA levels. The bile duct clearing resulted in a reduction of DB, AP, NO, MDA histological alterations and increase of portal flow. CONCLUSION: The biliary occlusion resulted in cholestasis and portal flow reduction, besides the increase of plasmatic NO and of hepatic MDA levels, and histological liver alterations, with a tendency of normalization after the bile duct clearing.

scholarly journals THERAPEUTIC PROFILING OF NANO ENCAPSULATED DIOSGENIN VIA ATTENUATING HORMONAL STATUS, CELL PROLIFERATION, INFLAMMATORY RESPONSES, AND APOPTOSIS IN AN ANIMAL MODEL OF MAMMARY ONCOGENESIS

2021 ◽  
pp. 126-132
Author(s):  
MANOBHARATHI VENGAIMARAN ◽  
KALAIYARASI DHAMODHARAN ◽  
MIRUNALINI SANKARAN
Keyword(s):  
Cell Proliferation ◽  
Molecular Docking ◽  
Cyclin D1 ◽  
Inflammatory Responses ◽  
Chitosan Nanoparticles ◽  
Hormonal Status ◽  
Sprague Dawley ◽  
Therapeutic Impact ◽  
Sprague Dawley Rats ◽  
Tnf Α

Objective: The central motive of this study is to explore the therapeutic impact of Diosgenin encapsulated Chitosan nanoparticles (DG@CS-NP) on mammary carcinogenesis in female Sprague Dawley rats via modulating hormonal status, cell proliferation, inflammatory responses, and Apoptosis. Methods: 7,12-dimethylbenz(a)anthracene (DMBA) was administered subcutaneously near the mammary gland (25 mg/kg b. wt) to provoke mammary tumor in female Sprague Dawley rats. Following the progress of a tumor, DMBA-induced tumor-bearing rats were medicated orally with 5 mg/kg b. wt of DG@CS-NP. Consequently, the expression of ER, PR, PCNA, Cyclin D1, NF-κB, TNF-α, Bcl-2, Caspases-3, and p53 in experimental rats were revealed via architectural immunohistochemistry. Further, Diosgenin interactions with these proteins were evidently confirmed by molecular docking analysis. Results: As a result, we noticed diminished levels of ER, PR, PCNA, Cyclin D1, NF-κB, TNF-α, and Bcl-2 expressions in DG@CS-NP medicated rats as well as with elevated levels of Caspases-3 and p53 expressions. In DMBA rats, the expressions were vice versa. Additionally, molecular docking analyses support these outcomes by highlighting the strong interaction between Diosgenin and breast cancer targets. Conclusion: These reports prove that DG@CS-NP imposes its therapeutic impact by hormonal adjustments, downregulating proteins involved in inflammation and cellular proliferation, and thereby promotes apoptosis by impeding apoptotic inhibitors.

Electroacupuncture attenuates vascular hyporeactivity in a rat model of portal hypertension induced by bile duct ligation

2021 ◽  
pp. 096452842110392
Author(s):  
Yu-Sheng Chen ◽  
Chorng-Kai Wen ◽  
Geng-Hao Liu ◽  
Tzung-Yan Lee
Keyword(s):  
Portal Hypertension ◽  
Growth Factor ◽  
Bile Duct ◽  
Bile Duct Ligation ◽  
Portal Pressure ◽  
Contractile Responses ◽  
Hyperdynamic Circulation ◽  
Duct Ligation ◽  
Tnf Α ◽  
Cox 1

Background: A hyperdynamic circulation and impaired vascular responsiveness to vasoconstrictors are observed in portal hypertension (PHT) rats. Inflammation is a major contributor to the hyperdynamic circulation state in murine models of PHT. Electroacupuncture (EA) may ameliorate the inflammatory response and limit arterial vasodilatation and portal pressure. This study investigated the possible mechanisms underlying putative hemodynamics effects of EA in normal and PHT rats. Methods: PHT was induced by bile duct ligation (BDL) surgery over 4 weeks in rats. Sham-operated and BDL rats were treated with low-frequency EA (2 Hz) at ST36 10 min three times weekly for one or two consecutive weeks (for a total of 3 or 7 treatments, respectively). Serum tumor necrosis factor-α (TNF-α), nitrite/nitrate (NOx) and 6-keto-prostaglandin F1α (6-keto-PGF1α) were analyzed, and hemodynamic variation and contractile responses to phorbol-12,13-dibutyrate and phenylephrine in aortic and superior mesenteric arterial rings were recorded. Inducible (i) and endothelial (3) nitric oxide synthase (NOS), cyclooxygenase-1 (COX-1), and protein kinase C-α (PKC-α) levels were determined by Western blotting. Results: EA significantly reduced portal pressure and serum TNF-α, NOx and 6-keto-PGF1α levels compared to the untreated BDL group, enhanced maximum contractile responses in the aorta, up-regulated PKC-α, and down-regulated iNOS and COX-1 levels. In addition, EA decreased the aortic angiogenesis signaling cascade, reflected by down-regulation of vascular endothelial growth factor (VEGF) abundance and transforming growth factor β receptor (TGFβR)I/II expression, as assessed by immunostaining. Conclusion: EA attenuates TNF-α, NO and 6-keto-PGF1α overproduction, modulates the vascular levels of constitutive NOS and PKC-α, blunts the development of the angiogenesis cascade, and enhances vascular contractile force in PHT rats.

Endogenous miR-21 and TIMP-1 Regulate Hepatic Injury and Fibrosis by Bile Duct Ligation in Vivo

2021 ◽  
Author(s):  
Chung-Hsin Lee ◽  
Yi-Chin Yang ◽  
Yi-Wen Hung ◽  
Ching-Chang Cheng ◽  
Yen-Chung Peng
Keyword(s):  
Bile Duct ◽  
Large Scale ◽  
Bile Duct Ligation ◽  
Inflammatory Responses ◽  
Histopathological Examination ◽  
Sprague Dawley ◽  
Functional Protein ◽  
Common Bile Duct Ligation ◽  
Simvastatin Treatment ◽  
Duct Ligation

Abstract TIMP metallopeptidase inhibitor 1 (TIMP-1) has been identified as a multifunctional molecule with divergent functions. It participates in wound healing and regeneration, cell morphology and survival, tumor metastasis, angiogenesis, and inflammatory responses. An imbalance of Matrix Metalloproteinase/TIMP regulation has been implicated in several inflammatory diseases. TIMP-1 could be considered an important regulator in the process of liver fibrosis and bile duct degeneration. Thus, we aimed to determine the role of TIMP-1 in a rat model of Common Bile Duct Ligation (CBDL). Male Sprague-Dawley rats were divided into several groups, including those with/ without CBDL surgery and those with/without amiodarone or simvastatin administration. Amiodarone/simvastatin treatment was given at a daily dose of 15 mg/kg and 18 mg/kg by means of intergalactic gavage, which began 7 days prior to CBDL induction. Two weeks after surgery, the animals in each group were sacrificed and hepatocyte degeneration severity was examined using histological morphologies. Large-scale array for secretory factors is intended for the purpose of finding key functional protein after CBDL. The hepatic level of miR-21 was determined through Taqman miRNA analysis. Furthermore, the TIMP-1 level in liver tissue was also visualized by histological stain. Liver injury and fibrosis were founded in CBDL rats based upon histopathological examination and serum biochemical analysis. Hepatic miR-21 and TIMP-1 were significantly up-regulated in CBDL rats, while being slightly rescued in response to amiodarone or simvastatin treatment. Up-regulation of miR-21 and TIMP-1 may result in the progression of hepatic cirrhosis after bile duct obstruction. Drug intervention for cirrhosis, like the use of statin, may function via similar mechanisms.

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