Liver Tissue Inducible Nitric Oxide Synthase (iNOS) Expression and Lipid Peroxidation in Experimental Hepatic Ischemia Reperfusion Injury Stimulated With Lipopolysaccharide: The Role of Aminoguanidine

Clinical characteristics of pyogenic liver abscess with and without biliary surgery history: a retrospective single-center experience

BACKGROUND & AIMS

Pyogenic liver abscess (PLA) is a common hepatobiliary infection that has been shown to have an increasing incidence, with biliary surgery being identified as a trigger. Our aim was to investigate the clinical characteristics and treatments of PLA patients with and without a history of biliary surgery (BS).

METHODS

The study included a total of 353 patients with PLA who received treatment at our hospital between January 2014 and February 2023. These patients were categorized into two groups: the BS group (n = 91) and the non-BS group (n = 262). In the BS group, according to the anastomosis method, they were further divided into bilioenteric anastomoses group (BEA, n = 22) and non-bilioenteric anastomoses group (non-BEA, n = 69). Clinical characteristics were recorded and analyzed.

RESULTS

The percentage of PLA patients with BS history was 25.78%. The BS group exhibited elevated levels of TBIL and activated APTT abnormalities (P = 0.009 and P = 0.041, respectively). Within the BS group, the BEA subgroup had a higher prevalence of diabetes mellitus (P < 0.001) and solitary abscesses (P = 0.008) compared to the non-BEA subgroup. Escherichia coli was more frequently detected in the BS group, as evidenced by positive pus cultures (P = 0.021). The BS group exhibited reduced treatment efficacy compared to those non-BS history (P = 0.020). Intriguingly, the BS group received a higher proportion of conservative treatment (45.05% vs. 21.76%), along with reduced utilization of surgical drainage (6.59% vs. 16.41%).

CONCLUSIONS

Patients with BS history, especially those who have undergone BEA, have an increased susceptibility to PLA formation without affecting prognosis.

Effects of iNOS in Hepatic Warm Ischaemia and Reperfusion Models in Mice and Rats: A Systematic Review and Meta-Analysis

Warm ischaemia is usually induced by the Pringle manoeuver (PM) during hepatectomy. Currently, there is no widely accepted standard protocol to minimise ischaemia-related injury, so reducing ischaemia-reperfusion damage is an active area of research. This systematic review and meta-analysis focused on inducible nitric oxide synthase (iNOS) as an early inflammatory response to hepatic ischaemia reperfusion injury (HIRI) in mouse- and rat-liver models. A systematic search of studies was performed within three databases. Studies meeting the inclusion criteria were subjected to qualitative and quantitative synthesis of results. We performed a meta-analysis of studies grouped by different HIRI models and ischaemia times. Additionally, we investigated a possible correlation of endothelial nitric oxide synthase (eNOS) and nitric oxide (NO) regulation with iNOS expression. Of 124 included studies, 49 were eligible for the meta-analysis, revealing that iNOS was upregulated in almost all HIRIs. We were able to show an increase of iNOS regardless of ischemia or reperfusion time. Additionally, we found no direct associations of eNOS or NO with iNOS. A sex gap of primarily male experimental animals used was observed, leading to a higher risk of outcomes not being translatable to humans of all sexes.

Hepatoprotective effect of ultrasonicated ginseng berry extract on a rat mild bile duct ligation model

Background

The Panax ginseng berry extract (GBE) is well known to have an antidiabetic effect. The aim of this study is to evaluate and investigate the protective effect of ultrasonication-processed P. ginseng berry extract (UGBE) compared with GBE on liver fibrosis induced by mild bile duct ligation (MBDL) model in rats. After ultrasonication process, the composition ratio of ginsenoside in GBE was changed. The component ratio of ginsenosides Rh1, Rh4, Rg2, Rg3, Rk1, Rk3, and F4 in the extract was elevated.

Methods

In this study, the protective effect of the newly developed UGBE was evaluated on hepatotoxicity and neuronal damage in MBDL model. Silymarin (150 mg/kg) was used for positive control. UGBE (100 mg/kg, 250 mg/kg, 500 mg/kg), GBE (250 mg/kg), and silymarin (150 mg/kg) were orally administered for 6 weeks after MBDL surgery.

Results

The MBDL surgery induced severe hepatotoxicity that leads to liver inflammation in rats. Also, the serum ammonia level was increased by MBDL surgery. However, the liver dysfunction of MBDL surgery–operated rats was attenuated by UGBE treatment via myeloid differentiation factor 88-dependent Toll-like receptor 4 signaling pathways.

Conclusion

UGBE has a protective effect on liver fibrosis induced by MBDL in rats through inhibition of the TLR4 signaling pathway in liver.

Hypericum Humifusum Leaves Attenuates Hepatic Ischemia-Reperfusion Injury in a Rat Model

INTRODUCTION

Effective prevention strategies require specific actions during the different phases of ischemia-reperfusion (I-R) injury. The objective of our study is to evaluate the effect of aqueous extract of Hypericum humifusum leaves (HHL) on liver I-R model in Rat.

MATERIAL AND METHODS

Animals were subjected to 90 min of hepatic ischemia followed by reperfusion (120 min). HHL extract (25 mg/mL/kg) was injected 15 min before reperfusion. To evaluate the effect of HHL extract on I-R, we have monitored transaminases levels, Malondialdehyde (MDA) concentration, histological lesions (apoptosis and necrosis) and compared the results to a reference oxidant vitamin E.

RESULTS

The determination of total phenol extracts of HHL was 59.91 ± 0.35 mg of Gallic Acid/g dry plant material with higher antioxidant activity (91.73% ± 1.67) compared to vitamin E (87.42%). Using aqueous extract of HHL, we noted a significant decrease of AST and ALT [1129 UI (585/1995) and 768 UI (335/1375)] compared to no-treated group [5,585.5 UI (5,035/12,070) and 8,099.5 UI (5,040/12,326)] as a decrease in MDA content [85.7% protection (50.9/91.5)]. HHL extract reduce the damage induced by I-R of 48.7% (27/48.7) and 96.1% (95.7/96.5) for necrosis and apoptosis lesions respectively.

CONCLUSION

HHL aqueous extract have potential to protect liver from the damage effect induced by I-R better than vitamin E solution.

Erythropoietin attenuates experimental haemorrhagic shock-induced renal damage through an iNOS- dependent mechanism in male Wistar rats

AIM

Erythropoietin (EPO) is shown to exert protective effects on different tissues in haemorrhagic shock (HS) states. Nitric oxide (NO), as a multifunctional signaling molecule, is implicated in diverse physiologic and pathologic processes. In order to understand the exact mechanism of EPO protection, in this study we evaluated the role of different NOS enzymes in the EPO signaling pathway in male rats.

METHODS

Rats were randomized to five groups: 1) Sham, 2) HS 3) EPO 4) L-NAME, a non-specific NOS inhibitor 5) 1400W, a specific iNOS inhibitor. HS was induced by withdrawal of 50% of total blood volume. After 2h, resuscitation was performed with the shed blood and Ringer's lactate. In group 3, rats were treated with EPO (300IU/kg, i.v.) over 10min before HS induction. In the L-NAME and 1400W groups, L-NAME (10mg/kg, i.p.) and 1400W (2mg/kg, i.p.) were administered 30min before EPO injection. Blood and kidney tissue samples were obtained 3h after resuscitation.

RESULTS

EPO increased the survival rate and significantly improved kidney function and histology compared to the HS group. There were less renal oxidative stress, apoptosis and systemic inflammatory responses in the EPO group. EPO increased eNOS and more abundantly iNOS mRNA expressions. L-NAME and 1400W significantly abolished all beneficial effects of EPO.

CONCLUSION

In this in vivo animal model, we showed that EPO administration prior to HS attenuates renal injury and dysfunction in rats. The protective effects of EPO may be mediated by nitric oxide and the expression of different NOS enzymes, especially iNOS isoform.

ADMA, SDMA and L-arginine may be Novel Targets in Pharmacotherapy for Complications due to Cardiopulmonary Bypass

Background

In this study, the effects of olmesartan therapy on asymmetric dimethylarginine (ADMA), symmetric dimethylarginine (SDMA), L-arginine and inducible nitric oxide synthase (iNOS) levels were investigated in patients undergoing cardiopulmonary bypass.

Methods

Patients were randomly allocated to two groups, control and olmesartan. Olmesartan was administered 30 mg once a day beginning from preoperative day 5 to postoperative day 28 and on operation day. Blood was drawn from all patients and ADMA, SDMA, L-arginine and iNOS levels were analyzed at six time points (T1: before anesthesia induction, T2: during cardiopulmonary bypass, T3: five min after the cross-clamp was removed, T4: after protamine infusion, T5: on postoperative day 3 and T6: on postoperative day 28).

Results

In the olmesartan treated group, iNOS levels exhibited significant decreases at T2, T3, T4, T5 and T6 time points compared with control group (p<0.001, p<0.05, p<0.001, p<0.01, p<0.05 respectively). ADMA levels were significantly lower in olmesartan treated group than in control group at T3, T4, T5 and T6 time points (p<0.05, p<0.05, p<0.05, p<0.01 respectively). SDMA levels at T2, T3 and T6 time points were higher in control group than olmesartan group. L-Arginine levels were significantly higher at T2 and T3 time points in olmesartan treated group than control group (p<0.001, p<0.01).

Conclusions

It was concluded that administration of olmesartan reduced plasma ADMA, SDMA, iNOS levels and enhanced L-arginine level in CPB time and it could reduce potential postoperative complications through reducing oxidative stress and inflammatory response in the postoperative period after coronary bypass surgery.

Pomegranate protects liver against cecal ligation and puncture-induced oxidative stress and inflammation in rats through TLR4/NF-κB pathway inhibition

Acute liver injury secondary to sepsis is a major challenge in intensive care unit. This study was designed to investigate potential protective effects of pomegranate against sepsis-induced acute liver injury in rats and possible underlying mechanisms. Pomegranate was orally given (800mg/kg/day) for two weeks before sepsis induction by cecal ligation and puncture (CLP). Pomegranate improved survival and attenuated liver inflammatory response, likely related to downregulation of mRNA expression of toll like recptor-4, reduced nuclear translocation and DNA binding activity of proinflammatory transcription factor NF-κB subunit p65, decreased mRNA and protein expression of tumor necrosis factor-alpha and reduction in myeloperoxidase activity and mRNA expression. Pomegranate also decreased CLP-induced oxidative stress as reflected by decreased malondialdehyde content, and increased reduced glutathione level and superoxide dismutase activity. These results confirm the antiinflammatory and antioxidant effects of pomegranate in CLP-induced acute liver injury mediated through inhibiting TLR4/NF-κB pathway, lipid peroxidation and neutrophil infiltration.

Cromoglycate, not ketotifen, ameliorated the injured effect of warm ischemia/reperfusion in rat liver: role of mast cell degranulation, oxidative stress, proinflammatory cytokine, and inducible nitric oxide synthase

Hepatic ischemia/reperfusion (ISCH/REP) is a major clinical problem that is considered to be the most common cause of postoperative liver failure. Recently, mast cells have been proposed to play an important role in the pathophysiology of ISCH/REP in many organs. In contrast, the role played by mast cells during ISCH/REP-induced liver damage has remained an issue of debate. This study aimed to investigate the protective role of mast cells in order to search for an effective therapeutic agent that could protect against fatal ISCH/REP-induced liver damage. A model of warm ISCH/REP was induced in the liver of rats. Four groups of rats were used in this study: Group I: SHAM (normal saline, intravenously [iv]); Group II: ISCH/REP; Group III: sodium cromoglycate + ISCH/REP (CROM + ISCH/REP), and Group IV: ketotifen (KET) + ISCH/REP (KET + ISCH/REP). Liver damage was assessed both histopathologically and biochemically. Mast cell degranulation was assessed histochemically. Lipid peroxidation (malondialdehyde [MDA]) as well as the levels of glutathione (GSH), interleukin-6 (IL-6), and tumor necrosis factor alpha (TNF-α), the formation of nitric oxide (NO), and the expression of inducible NO synthase (iNOS) were determined. The results of this study revealed increased mast cell degranulation in the liver during the acute phase of ISCH/REP. Moreover, CROM, but not KET, decreased the activity of alanine aminotransferase, aspartate aminotransferase, and lactic dehydrogenase and maintained normal liver tissue histology. Both CROM and KET protected against mast cell degranulation in the liver. In addition, both CROM and KET decreased IL-6 and TNF-α. However, CROM, but not KET, decreased MDA formation and increased GSH. Furthermore, KET, but not CROM, increased both NO formation and iNOS expression. In conclusion, this study clearly demonstrated mast cell degranulation in warm ISCH/REP in the liver of rats. More importantly, CROM, but not KET, ameliorated the effect of ISCH/REP-induced injury in rat liver. CROM may protect the liver through mast cell stabilization, inhibition of TNF-α, IL-6, MDA, and iNOS and increased GSH. KET may maintain ISCH/REP-induced liver injury through the NO/iNOS pathway.

Organ-Protective Effects of Red Wine Extract, Resveratrol, in Oxidative Stress-Mediated Reperfusion Injury

Resveratrol, a polyphenol extracted from red wine, possesses potential antioxidative and anti-inflammatory effects, including the reduction of free radicals and proinflammatory mediators overproduction, the alteration of the expression of adhesion molecules, and the inhibition of neutrophil function. A growing body of evidence indicates that resveratrol plays an important role in reducing organ damage following ischemia- and hemorrhage-induced reperfusion injury. Such protective phenomenon is reported to be implicated in decreasing the formation and reaction of reactive oxygen species and pro-nflammatory cytokines, as well as the mediation of a variety of intracellular signaling pathways, including the nitric oxide synthase, nicotinamide adenine dinucleotide phosphate oxidase, deacetylase sirtuin 1, mitogen-activated protein kinase, peroxisome proliferator-activated receptor-gamma coactivator 1 alpha, hemeoxygenase-1, and estrogen receptor-related pathways. Reperfusion injury is a complex pathophysiological process that involves multiple factors and pathways. The resveratrol is an effective reactive oxygen species scavenger that exhibits an antioxidative property. In this review, the organ-protective effects of resveratrol in oxidative stress-related reperfusion injury will be discussed.

Effect of aminoguanidine on sciatic functional index, oxidative stress, and rate of apoptosis in an experimental rat model of ischemia-reperfusion injury

This study was conducted to investigate the potential protective effects of aminoguanidine (AG) on sciatic functional index (SFI), oxidative stress status, and apoptosis index using a rat model of experimental sciatic nerve ischemia-reperfusion injury (I/R). Treatment groups received 150 mg AG/kg body mass, 24 h after the induction of ischemia. After reperfusion for 2, 4, 7, 14, and 28 days, we evaluated measured SFI, plasma antioxidant enzymes, total antioxidant capacity (TAC), malondialdehyde (MDA), and index of apoptosis. SFI was significantly improved on the 7th and 14th day of reperfusion in the AG-treated groups. AG treatment resulted in the significant reduction of MDA levels on the 7th and 14th day of reperfusion. TAC was only increased after 7 days of reperfusion compared with the untreated group. SOD activity was decreased in both the untreated and AG-treated groups by comparison with the control, but did not show a significant change. GPx activity decreased only after 7 days of reperfusion. The maximal rate of apoptosis occurred on the 7th day of reperfusion. Treatment with AG significantly reduced this enhancement. AG exhibits positive effects against sciatic nerve I/R injury, possibly in part because of the protective effects of AG against apoptosis and I/R-induced oxidative stress.

Preventive role of gallic acid on hepatic ischemia and reperfusion injury in rats

There is little information about the hepatoprotective effects of gallic acid against ischemia-reperfusion (I/R) damage. Animals were subjected to I/R. Gallic acid at doses of 50 and 100 mg/kg body weight (bw) were injected as a single dose prior to ischemia. Liver tissue homogenates were used for the measurement of malondialdehyde (MDA), catalase (CAT) and glutathione peroxidase (GPx) levels. At the same time alanine aminotransferase (ALT), aspartate aminotransferase (AST) and lactate dehydrogenase (LDH) were assayed in serum samples and compared statistically. While the ALT, AST, LDH activities and MDA levels were significantly increased, CAT and GPx activities significantly decreased in only I/R-induced control rats compared to normal control rats (P < 0.05). Treatment with gallic acid at a dose of 100 mg/kg bw significantly decreased the ALT, AST, LDH activities and MDA levels, and markedly increased activities of CAT and GPx in tissue homogenates compared to I/R-induced rats with no treatment group (P < 0.05). In oxidative stress generated by hepatic ischemia-reperfusion, gallic acid contributes partially an alteration in the delicate balance between the scavenging capacity of antioxidant defense systems and free radicals in favour of the antioxidant defense systems in the body.

Inducible nitric oxide synthase inhibition reverses pulmonary arterial dysfunction in lung transplantation

BACKGROUND

Ischemia-reperfusion injury (IRI) after lung transplantation remains a significant cause of morbidity and mortality. Lung IRI induces nitric oxide synthesis (iNOS) and reactive nitrogen species, decreasing nitric oxide bioavailability. We hypothesized that ischemia-induced iNOS intensifies with reperfusion and contributes to IRI-induced pulmonary arterial regulatory dysfunction, which may lead to early graft failure and cause pulmonary edema. The aim of this study was to determine whether ischemia-reperfusion alters inducible and endothelial nitric oxide synthase expression, potentially affecting pulmonary perfusion. We further evaluated the role of iNOS in post-transplantation pulmonary arterial disorder.

METHODS

We randomized 32 Sprague-Dawley rats into two groups. The control group was given a sham operation whilst the experimental group received orthotropic lung transplants with a modified three-cuff technique. Changes in lung iNOS, and endothelial nitric oxide synthase expression were measured after lung transplantation by enzyme-linked immunosorbent assay (ELISA). Vasoconstriction in response to exogenous phenylephrine and vasodilation in response to exogenous acetylcholine of pulmonary arterial rings were measured in vitro as a measure of vascular dysfunction. To elucidate the roles of iNOS in regulating vascular function, an iNOS activity inhibitor (N6-(1-iminoethyl)-L-lysine, L-NIL) was used to treat isolated arterial rings. In order to test whether iNOS inhibition has a therapeutic effect, we further used L-NIL to pre-treat transplanted lungs and then measured post-transplantation arterial responses.

RESULTS

Lung transplantation caused upregulation of iNOS expression. This was also accompanied by suppression of both vasoconstriction and vasodilation of arterial rings from transplanted lungs. Removal of endothelium did not interfere with the contraction of pulmonary arterial rings from transplanted lungs. In contrast, iNOS inhibition rescued the vasoconstriction response to exogenous phenylephrine of pulmonary arterial rings from transplanted lungs. In addition, lung transplantation led to suppression of PaO2/FiO2 ratio, increased intrapulmonary shunt (Q s/Q t), and increase of lung wet to dry ratio (W/D), malondialdehyde and myeloperoxidase levels, all of which were reversed upon iNOS inhibition. Furthermore, inhibition of iNOS significantly rescued vascular function and alleviated edema and inflammatory cell infiltration in the transplanted lung.

CONCLUSIONS

Our data suggest that lung transplantation causes upregulation of iNOS expression, and pulmonary vascular dysfunction. iNOS inhibition reverses the post-transplantational pulmonary vascular dysfunction.

Effects of aminoguanidine on retinal apoptosis in mice with oxygen-induced retinopathy

AIM

To explore the protective effects of aminoguanidine (AG) on retinal apoptosis in mice with oxygen-induced retinopathy (OIR).

METHODS

A total of 80 C57BL/6J mice, aged 7 days, were randomly divided into four groups: normal, high oxygen, high oxygen saline and high oxygen treated with AG. In the normal group, mice were housed in normoxic conditions from postnatal day P7 to P17. Mice in the other 3 groups were placed under hyperoxic conditions (75±2%O2) in an oxygen-regulated chamber for 5 days and subsequently placed in normoxic conditions for 5 days. Mice in the AG group were treated once daily, from P12 to P17, with AG hemisulfate (100mg/kg body weight, intraperitoneally) dissolved in physiological saline. An equivalent amount of 0.9% physiological saline was administered, as above, to mice in the high oxygen saline group. Ten mice were randomly selected from each group on P14 and on P17, euthanized and the retinas examined. Apoptotic cells in the retina were detected using the terminal-deoxynucleoitidyl transferase mediated nick end labeling (TUNEL) method. The expression of nitric oxide synthase (iNOS) in the retina was detected by immunohistochemistry and changes in rod cells were observed using electron microscopy.

RESULTS

TUNEL-positive cells and iNOS immunoreactive neurons were present in the inner nuclear and ganglion cell retinal layers of mice in the high oxygen group. The number of TUNEL-positive cells was significantly greater in the high oxygen group compared with the normal group (t=-20.81, P 14d <0.05; t=-15.05, P 17d <0.05). However, the number of TUNEL-positive cells in the AG treatment group was significantly lower (t=-13.21, P 14d<0.05; t=-6.61, P 17d <0.05) compared with the high oxygen group. The expression of iNOS was significantly higher in the high oxygen group compared with the normal group (t=-21.95, P 14d<0.05; t=-17.30, P 17d<0.05). However, the expression of iNOS in the AG treatment group was significantly lower (t=-12.17, P 14d<0.05; t=-10.30, P 17d<0.05) compared with the high oxygen group. The outer segments of the rods were disorganized and short in the high oxygen group. Rod morphology appeared to be slightly improved in the AG group.

CONCLUSION

AG may protect retinal neurons in OIR by inhibiting apoptosis. The mechanism may be related to iNOS.

The hepatoprotective effects of Hypericum perforatum L. on hepatic ischemia/reperfusion injury in rats

Little is known about the effective role of Hypericum perforatum on hepatic ischemia-reperfusion (I/R) injury in rats. Hence, albino rats were subjected to 45 min of hepatic ischemia followed by 60 min of reperfusion period. Hypericum perforatum extract (HPE) at the dose of 50 mg/kg body weight (HPE50) was intraperitonally injected as a single dose, 15 min prior to ischemia. Rats were sacrificed at the end of reperfusion period and then, biochemical investigations were made in serum and liver tissue. Liver tissue homogenates were used for the measurement of malondialdehyde (MDA), catalase (CAT) and glutathione peroxidase (GPx) levels. At the same time alanine aminotransferase (ALT), aspartate aminotransferase (AST) and lactate dehydrogenase (LDH) were assayed in serum samples and compared statistically. While the ALT, AST, LDH activities and MDA levels were significantly increased, CAT and GPx activities significantly decreased in only I/R-induced control rats compared to normal control rats (p < 0.05). Treatment with HPE50 significantly decreased the ALT, AST, LDH activities and MDA levels, and markedly increased activities of CAT and GPx in tissue homogenates compared to I/R-induced rats without treatment-control group (p < 0.05). In oxidative stress generated by hepatic ischemia-reperfusion, H. perforatum L. as an antioxidant agent contributes an alteration in the delicate balance between the scavenging capacity of antioxidant defence systems and free radicals in favour of the antioxidant defence systems in the body.

Serum nitric oxide levels in patients with benign and malignant biliary disease: a prospective single center study

BACKGROUND

Despite advances in new diagnostic modalities, the differentiation of malignant from benign causes of biliary obstruction still remains difficult. The nitric oxide (NO) system is considered to be an important component in mediating cytokine activation of macrophages in inflammation. It also modulates tumorigenesis and regulates cell proliferation, angiogenesis, survival, and DNA repair. Although NO and its role in pancreatobiliary disorders has not been studied previously, the present study is designed to evaluate NO synthesis and metabolism in patients with biliary obstruction and to determine its usefulness in differentiating between benign and malignant causes of biliary obstruction.

MATERIALS AND METHODS

Seventy-nine consecutive patients (60 malignant and 19 benign) with a history of biliary obstruction either with a benign or a malignant cause and 23 age-matched and sex-matched controls were included in this prospective study. NO metabolites, and conventional inflammation and tumor markers were determined.

RESULTS

In patients with malignant biliary obstruction (MBO), serum NO metabolites were found to be significantly elevated (P<0.001). The receiver operating characteristic analysis showed that an NO level of 1.095 was the best cut-off value for predicting a malignant biliary stricture with a sensitivity of 78.3% and a specificity of 84.2% (area under the curve=0.821). Correlation analysis suggested that carbohydrate antigen 19-9 and carcinoembryonic antigen levels were correlated with NO levels for differentiating benign from malignant cause of biliary obstruction.

CONCLUSIONS

Serum NO-associated tissue injury might be associated with the development of pancreatobiliary neoplasia by creating a local environment that is enriched with reactive oxygen species, cytokines, and other growth factors that may promote endothelial cell apoptosis. Moreover, serum NO levels may be used as an adjunctive marker to identify malignant causes of the obstructive jaundice.

Extraction optimization of Angelica sinensis polysaccharides and its antioxidant activity in vivo

Extraction of Angelica sinensis polysaccharides (ASP) was optimized by the utilization of response surface methodology, RSM. Through the analysis, extraction time and water/solid were found to be the most significant factors. Based on contour plots and variance analysis, optimum operational conditions for maximizing polysaccharides yield (5.6%) were found to be extraction time 130 min, water/solid 5, and extraction number 5. A. sinensis polysaccharides (150 and 300 mg/kg) were administered for 15 days. The hepatoprotective activity was assessed using various biochemical parameters. Serum aspartate aminotransferase (AST), alanine aminotransfere (ALT) and alkaline phosphatase (ALP) levels were significantly restored toward normalization by the extracts (150 and 300 mg/kg body weight). ASP (150 and 300 mg/kg body weight) significantly increased the levels of antioxidant enzymes. It can be concluded that ASP possesses significant protective effect against hepatotoxicity induced by carbon tetrachloride (CCl4). This protective effect appears due to ASP antioxidant properties.

Mechanism investigation of dioscin against CCl4-induced acute liver damage in mice

The mechanisms of the ameliorating effects of dioscin against CCl(4) induced acute liver damage are investigated in this study. Dioscin significantly inhibited (p<0.01) the increases of serum ALT and AST activities compared with the CCl(4)-treated animals. The hepatic lipid peroxidation formation and, concentrations of TNF-α and IL-6 were also decreased. Liver histopathologic studies and a DNA laddering assay indicated that dioscin protected hepatocytes against CCl(4)-induced apoptosis and necrosis. Furthermore, dioscin decreased the protein expressions of Fas/FasL, increased Bcl-2/Bax ratio, inhibited the release of cytochrome c from mitochondrion to cytosol and attenuated CCl(4)-induced caspase-3 and -8 activities. The expressions of ICAM-1, vimentin, prohibitin, HGF, c-MET and GSTA1 were also regulated by dioscin and iNOS was also involved in the effects of this agent. These protective effects against CCl(4) induced acute liver damage might be through inhibiting lipid peroxidation, inflammatory cytokines, necrosis and apoptosis, and dioscin shows promise for development toward the treatment of acute chemically mediated liver injury.

Dexmedetomidine protects against lipid peroxidation and erythrocyte deformability alterations in experimental hepatic ischemia reperfusion injury

Background

Hepatic ischemia–reperfusion injury is a common clinical problem in hepatic surgery and transplantation. Several cellular and tissue structural and functional alterations are observed in such injury. The aim of this study was to evaluate the effect of dexmedetomidine on lipid peroxidation and erythrocyte deformability during ischemia–reperfusion injury in rats.

Methods

Twenty-four Wistar Albino rats were randomly separated into three groups as control (C), ischemia–reperfusion injury (I/R) and dexmedetomidine group (I/R-D). Ischemia was induced with portal clampage for 45 min and reperfusion period was 45 min after declampage. Group I/R-D received dexmedetomidine 100 µg/kg i.p. 30 min before portal clampage. Serum malondialdehyde and superoxide dismutase activities to document lipid peroxidation and erythrocyte deformability index were investigated.

Results

Serum superoxide dismutase and malondialdehyde activity levels were significantly higher and erythrocyte deformability index was decreased in hepatic ischemia–reperfusion group. However, these changes were observed to be prevented with dexmedetomidine treatment when given before portal clampage.

Conclusion

These findings clearly indicate that erythrocyte deformability index is decreased in hepatic ischemia reperfusion injury and has a potential role to prevent these alterations. The protective effect of dexmedetomidine on hepatic I/R injury is also decreased lipid peroxidation. Further experimental and clinical investigations may clarify the molecular mechanisms and clinical significance of these findings.

The relative efficacy of aminoguanidine and pentoxifylline in modulating endotoxin-induced cardiac stress

This study investigates the effect of aminoguanidine (AG), a selective inducible nitric oxide synthase (iNOS) inhibitor, and pentoxifylline (PTX), a tumour necrosis factor-alpha (TNF-α) inhibitor, on lipopolysaccharide (LPS)-induced cardiac stress. Rats were divided into four groups: group I served as a control, group II (LPS) received a single intraperitoneal injection of LPS (10 mg·kg(-1) ), group III (LPS+AG) and group IV (LPS+PTX) were injected with either AG (100 mg·kg(-1) ) or PTX (150 mg·kg(-1) ) intraperitoneally 10 days prior to LPS administration. Normalization of cardiac levels of nitrite/nitrate (NO(X) ), malondialdehyde (MDA), glutathione (GSH), heme oxygenase-1 (HO-1), glutathione peroxidase (GPx) and Na(+) , K(+) -ATPase activities was evident in the AG group. Both AG and PTX decreased the elevated serum TNF-α levels, the activities of lactate dehydrogenase (LDH), creatine kinase (CK) and cardiac myeloperoxidase (MPO). The levels of adenosine triphosphate (ATP), adenosine diphosphate (ADP) and phosphocreatine (PCr) were enhanced following AG and PTX pretreatments. Calcium (Ca(2+) ) levels were altered, and the histopathological observations supported the described results. Conclusively, the study highlights the cardioprotective potential of AG and PTX with superior results from AG. These findings reveal the relative contribution of nitric oxide and TNF-α to oxidative stress and energy failure during endotoxemia.

C/EBPα and C/EBPβ binding proteins modulate hepatocyte apoptosis through iNOS signaling pathway

Inducible nitric oxide synthase (iNOS) and nitric oxide (NO) involve many pathophysiologic conditions. The expression of iNOS is regulated at multiple stages. Presently, the regulatory details of iNOS signaling are still unclear. This study aimed to investigate the regulatory role of C/EBPα and C/EBPβ in iNOS signaling pathway. By employing the techniques such as EMSA, ChIP assay, site-directed mutagenesis, and siRNA silencing, the relationship between iNOS and C/EBPα/C/EBPβ in rat hepatocytes was clarified. iNOS promoter was the direct transcriptional targets of the C/EBPα, C/EBPβ, and NF-κB binding proteins. There was the interactive influence between NF-κB and C/EBPα/C/EBPβ. The expression of iNOS was modulated by C/EBPα/C/EBPβ transcription factors. Moreover, the iNOS expression mediated glycochenodeoxycholate (GCDC)-induced apoptosis in hepatocytes. C/EBPα/C/EBPβ binding proteins could affect the GCDC-induced apoptosis through iNOS cascade. These findings indicate that C/EBPα and C/EBPβ regulate the iNOS expression, which may further modify cell responses such as apoptosis and cell survival.

Montelukast, a leukotriene receptor antagonist abrogates lipopolysaccharide-induced toxicity and oxidative stress in rat liver

Endotoxemia-induced hepatotoxicity is characterized by disturbed intracellular redox balance, excessive reactive oxygen species (ROS) generation inducing DNA, proteins and membrane lipid damages. In the present study, the protective effects of montelukast (MNT) against Escherichia coli lipopolysaccharides (LPS)-induced oxidative stress were investigated in rat liver. LPS (10mg/kg, i.p.) was injected and the animals were sacrificed 6h after LPS challenge. MNT (10mg/kg) was administered orally for seven successive days before endotoxemia induction. Blood samples were withdrawn for assessing the activities of alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), lactate dehydrogenase (LDH) and levels of serum total bilirubin, total protein, tumor necrosis factor-alpha (TNF-α) and interleukin 1β (IL-1β). Livers were dissected out and used for histological examination or stored for the determination of malondialdehyde (MDA), protein carbonyl content (PCC), reduced glutathione (GSH) levels, enzymatic activities of catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and myeloperoxidase (MPO). Sepsis significantly increased ALT, AST, ALP, LDH, total bilirubin, TNF-α and IL-1β, MPO, MDA and PCC levels and decreased total protein, GSH and enzymatic antioxidants (CAT, SOD and GSH-Px). MNT decreased the markers of liver injury (AST, ALT, ALP, LDH, and total bilirubin), inflammatory biomarkers (TNF-alpha, IL-1β), MDA, PCC and MPO after LPS challenge. In conclusion, MNT abrogates LPS-induced markers of liver injury and suppresses the release of inflammatory and oxidative stress markers via its antioxidant properties and enhancement enzymatic antioxidant activities.

The strategy of combined ischemia preconditioning and salvianolic acid-B pretreatment to prevent hepatic ischemia-reperfusion injury in rats

BACKGROUND

Ischemia-reperfusion injury (IRI) is a serious complication of liver surgery, especially for extended hepatectomy and liver transplantation. The aim of this study was to evaluate the protective effect of combined ischemic preconditioning (IPC) and salvianolic acid-B (Sal-B) pretreatment against IRI-induced hepatocellular injury.

METHODS

Sixty male Wistar rats weighing around 200 g were randomized into five groups (n=12): sham group: only anesthesia and laparotomy; IR group: 90 min sustained ischemia by blocking the left ortal vessels; IPC group: 10 min ischemia and 10 min reperfusion prior to the sustained ischemia; Sal-B group: 10 mg/kg injection of Sal-B intravenously 10 min prior to the sustained ischemia; IPC+Sal-B group: same IPC procedure as in IPC group, but proceeded by intravenous administration of Sal-B 10 min prior to sustained ischemia. After 5 h of reperfusion, serum levels of ALT and AST were measured; the amount of malondialdehyde (MDA) and adenine nucleotides in liver tissue was determined; the expression of Bcl-2 and caspase-3 was detected by immunofluorescent and western blotting techniques; the severity of apoptosis and pathological alterations was evaluated by TUNEL and H&E staining, respectively.

RESULTS

The serum aminotransferases, hepatic MDA concentration, and apoptotic index in groups IPC, Sal-B, and IPC+Sal-B were significantly lower than those in the IR group (P<0.001), while the IPC+Sal-B group had the lowest values among these groups (P<0.05). Compared with the IR group, groups IPC and Sal-B not only had statistically higher ATP levels and energy charge (EC) values (P<0.01), but also had upregulated Bcl-2 expression and downregulated cleaved caspase-3 expression in liver tissue. All these effects were further augmented in the IPC+Sal-B group. Liver histopathological findings were consistent with these results.

CONCLUSIONS

Based on these results, the combined IPC and Sal-B pretreatment had a synergistically protective effect on liver tissue against IRI, which might be due to decreased post-ischemic oxidative stress, improved energy metabolism, and reduced hepatocellular apoptosis.

The role of erythropoietin in hemorrhagic shock-induced liver and renal injury in rats

INTRODUCTION

The aim of the present study was to evaluate the role of erythropoietin (EPO) in liver and renal injury following hemorrhagic shock (HS) after inhibition of tyrosine kinase activity in rats..

METHODS

Forty-eight Sprague-Dawley rats were assigned to six groups: (I) HS alone; (II) HS followed by retransfusion; (III) EPO and genistein followed by HS; (IV) EPO and genistein followed by HS, followed by retransfusion; (V) HS followed by EPO and genistein; and (VI) HS followed by EPO and genistein, followed by retransfusion. HS was induced for 60 minutes after withdrawal of 30% of the calculated total blood volume of each rat from the left femoral artery. Blood and tissue samples (from the kidney and liver) were obtained 60 minutes after HS in Group I, III, and V; blood and tissue samples were obtained 60 minutes after retransfusion in Group II, IV, and VI. In Group III and IV, EPO was given 60 minutes before HS, and genistein 30 minutes before HS. In Group V and VI, EPO and genistein were given 30 minutes after HS.

RESULTS

Liver and renal injury were significantly attenuated with EPO and genistein administration.

CONCLUSION

These results suggest that EPO is effective in attenuating liver and renal injury in HS, even with inhibition of tyrosine kinase activity with genistein.