Protective effects of n-acetylcysteine on lung injury and red blood cell modification induced by carrageenan in the rat

Inhibitory effect of hydroalcoholic extract of Cunila spicata Benth. on phlogistic agents-induced cellular migration in the airways of mice

ETHNOPHARMACOLOGICAL RELEVANCE

Cunila spicata Benth. Is a creeping and aromatic plant that has an ethnopharmacological indication in the southern region of Brazil, in the Araucaria Forest biome. It's used as an alternative therapy for respiratory diseases for men and animals since the "tropeirista" movement in colonial Brazil.

AIM OF THE STUDY

Investigate the influence of oral administration of hydroalcoholic extract of C. spicata (HECS) on cellular inflammatory processes in the airways of mice.

MATERIAL AND METHODS

The HECS was obtained by the ultrasound-assisted technique. Phytochemical analysis of the volatile compounds was performed using gas-chromatography with mass spectrometry. To investigate the biological activity of HECS, the animals were pre-treated with HECS orally 1 h before and the bronchoalveolar lavage (BAL) model was used, in which the animals were subjected to inhalation of different pro-inflammatory agents such as carrageenan (CAR), histamine (HIST), capsaicin (CAP), bradykinin (BK), and 48/80 compound (C48/80). After sacrifice, BAL sample was collected from the bronchi and was analyzed for total and differential white blood cell counts, compared with control groups.

RESULTS

Fourteen volatile phytocompounds were identified in the HECS, the main ones being 2-bornanone, menthofuran and camphene. Among the HECS treated animals, all showed significant maximal inhibition (MI) when challenged with pro-inflammatory agents by nebulization. In the group of animals that received CAR, the MI was 72.77 ± 3.88%, compared to the negative control (NC). There was a predominance of lymphocytes (59.18 ± 4.07%). For the HIST group, MI was 64.03 ± 4.33%, in relation to the NC, with predominance in macrophages number (76.53 ± 2.78%). In the CAP group, the MI obtained was 38.90 ± 11.31%, with greater macrophage migration occurring (80.98 ± 3.44%) in the higher dose. For animals subjected to BK inhalation, the MI was 48.63 ± 3.95% with macrophages predominance (64.33 ± 10.04%). In the group that received C48/80 inhalation, the MI was 40.25 ± 5.30% (100 mg kg^-1), with higher occurrence of macrophages (72.97 ± 4.23%).

CONCLUSION

Our results suggest that HECS had a non-specific inhibitory effect on cellular migration induced by different pro-inflammatory agents, reducing inflammation in airways of mice. These effects coincide and support its ethnopharmacological use as an alternative medicine for respiratory diseases in regions where the plant is prevalent.

Targeting Oxidative Stress as a Therapeutic Approach for Idiopathic Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic interstitial lung disease characterized by an abnormal reepithelialisation, an excessive tissue remodelling and a progressive fibrosis within the alveolar wall that are not due to infection or cancer. Oxidative stress has been proposed as a key molecular process in pulmonary fibrosis development and different components of the redox system are altered in the cellular actors participating in lung fibrosis. To this respect, several activators of the antioxidant machinery and inhibitors of the oxidant species and pathways have been assayed in preclinical in vitro and in vivo models and in different clinical trials. This review discusses the role of oxidative stress in the development and progression of IPF and its underlying mechanisms as well as the evidence of oxidative stress in human IPF. Finally, we analyze the mechanism of action, the efficacy and the current status of different drugs developed to inhibit the oxidative stress as anti-fibrotic therapy in IPF.

Oxidative Stress and Endothelial Dysfunction in Sepsis and Acute Inflammation

Significance: Under homeostatic conditions, the endothelium dynamically regulates vascular barrier function, coagulation pathways, leukocyte adhesion, and vasomotor tone. During sepsis and acute inflammation, endothelial cells (ECs) undergo multiple phenotypic and functional modifications that are initially adaptive but eventually become harmful, leading to microvascular dysfunction and multiorgan failure. Critical Issues and Recent Advances: Sepsis unbalances the redox homeostasis toward a pro-oxidant state, characterized by an excess production of reactive oxygen species and reactive nitrogen species, mitochondrial dysfunction, and a breakdown of antioxidant systems. In return, oxidative stress (OS) alters multiple EC functions and promotes a proinflammatory, procoagulant, and proadhesive phenotype. The OS also induces glycocalyx deterioration, cell death, increased permeability, and impaired vasoreactivity. Thus, during sepsis, the ECs are both a significant source and one of the main targets of OS. Future Directions: This review aims at covering the current understanding of the role of OS in the endothelial adaptive or maladaptive multifaceted response to sepsis and to outline the therapeutic potential and issues of targeting OS and endothelial dysfunction during sepsis and septic shock. One of the many challenges in the management of sepsis is now based on the detection and correction of these anomalies of endothelial function.

Elucidating Molecular Interactions of Ten Natural Compounds Targeting E6 HPV High Risk Oncoproteins Using Microsecond Molecular Dynamics Simulations

BACKGROUND

Cervical cancer is a major public health issue worldwide, occurring in the vast majority of cases (85%) in low-income countries. Human papillomavirus (HPV) mainly infects the mucosal epithelium, and a small portion causes over 600,000 cases every year worldwide at various anatomical spots, mainly leading to anogenital and head and neck.

INTRODUCTION

The E6 oncoprotein encoded by cancer-associated alpha HPV can transform epithelial cells into tumorigenic tissue. Therapy for this infection and blocking of the HPV E6 oncoprotein could be provided with cost-effective and abundant natural products which are an exponentially growing topic in the literature. Finding an active natural compound that readily blocks HPV E6 oncoprotein which could be available for developing countries without expensive extraction processes or costly synthetic pathways is of major interest.

METHODS

Molecular dynamics simulation was performed using the most up-to-date AMBER protein force field ff14SB and a GPU enabled high performance computing cluster.

RESULTS

In this research, we present a study of the binding properties between 10 selected natural compounds that are readily available with two variants of the E6 oncoprotein types (HPV-16 and HPV-18) using 10+ microsecond molecular dynamics simulations.

CONCLUSION

Our results suggest that crocetin, ergosterol peroxide and κ-carrageenan natural products bind strongly to both HPV-16 and HPV-18 and could potentially serve as a scaffolding for further drug development.

Therapeutic potential of sulfur-containing natural products in inflammatory diseases

Owing to the prevalence of chronic inflammation and its related disorders, there is a demand for novel therapeutic agents capable of preventing or suppressing inflammation. Natural products (NPs) are well established as an important resource for drug development and provide an almost infinite array of molecular entities. Sulfur-containing NPs (i.e., NPs containing one or more sulfur atoms) are abundant throughout nature, from bacteria to animals. The aim of this review was to survey the emerging evidence on role of sulfur-containing NPs, such as glutathione, garlic-derived sulfur compounds, Epipolythiodioxopiperazines (EPTs), Isothiocyanates (ITCs), and Ergothioneine (EGT), in the control of inflammation and to determine the possible underlying mechanisms. A discussion of how hydrogen sulfide (H₂S), an endogenous gaseous signaling molecule, links sulfur-containing NPs and their anti-inflammatory action is also performed. This review may help to further the development of sulfur-based compounds by providing a guide for structure-activity relationship-based modification for use in modern medicinal chemistry. However, as this field is still in its infancy, the review is concluded by an overview of the progression of these promising entities as therapeutic agents.

Anti-Inflammatory Profile of Jungia sellowii Less. by Downregulation of Proinflammatory Mediators and Inhibition of NF-κB and p38 Pathways

Jungia sellowii Less. (Asteraceae) is a native plant found in Southeast Brazil used traditionally to treat inflammatory diseases. This study was conducted (1) to investigate the toxicity of the crude extract (CE) and (2) to investigate the mechanism of the anti-inflammatory action of J. sellowii L. roots. The potential acute toxicity of CE was performed by administration of only different doses of CE (500, 1,000, and 2,000 i.p.) on mice for 14 days. The anti-inflammatory effect was evaluated using carrageenan-induced acute pleural cavity inflammation in a mouse model, evaluated through the following inflammatory variables: leukocyte, protein concentrations of the exudate, myeloperoxidase (MPO), adenosine deaminase (ADA), nitric oxide metabolites (NO_x), and proinflammatory cytokine (tumor necrosis factor alpha (TNF-α), interferon gamma (IFN-γ), interleukin- (IL-) 6, and IL-12) levels in mouse pleural fluid leakage. The p65 protein phosphorylation of nuclear factor NF-kappa B (p65 NF-κB) and p38 mitogen-activated protein kinase (p38 MAPK) phosphorylation were analyzed in lung tissue. Our results demonstrated that the administration of CE up to 2,000 mg/kg did not present a toxic effect. In addition, the pretreatment of mice with CE; its derived fractions (aqueous fraction (AqF), butanol fraction (BuOHF), and ethyl acetate fraction (EtOAcF)); and isolated compounds (curcuhydroquinone O-β-glucose (CUR) and α and β piptizol (Pip)) reduced the following inflammatory variables: neutrophils, protein concentrations of the exudate, MPO, ADA, NO_x, and proinflammatory cytokine (TNF-α, IFN-γ, IL-6, and IL-12) levels in mouse pleural fluid leakage. The compounds CUR and Pip also decreased the p65 protein phosphorylation of NF-kappa B and p38 (MAPK) in lung tissue. J. sellowii L. has important anti-inflammatory activity with potential applications in drug development against inflammatory disorders. These effects found can be attributed to the ability of the new isolated compounds CUR and Pip to suppress p65 NF-κB and p-p38 MAPK pathways.

Considering the Effect of Rosa damascena Mill. Essential Oil on Oxidative Stress and COX-2 Gene Expression in the Liver of Septic Rats

OBJECTIVES

Sepsis is a clinical illness with a high rate of mortality all over the world. Oxidative stress is considered the main phenomenon that occurs in sepsis. Rosa damascena Mill. is an ancient herbal plant with high pharmacological activities.

MATERIALS AND METHODS

Cecal ligation and puncture (CLP) as a standard model was used to induce sepsis in rats. Male adult rats were randomly divided into 5 groups. Different doses of R. damascena essential oil (50 and 100 mg/kg.bw) were gavaged orally for 14 days and on day 15 CLP was performed. After 24 h, blood samples and liver tissues were removed in order to measure oxidative stress [myeloperoxidase (MPO), malondialdehyde (MDA), glutathione (GSH), glutathione-S-transferase, and ferric reducing ability of plasma (FRAP)] and biochemical parameters [alkaline phosphatase (ALP), aspartate transaminase (AST), alanine transaminase (ALT), and bilirubin] together with plasma prostaglandin E2 (PGE2) and COX-2 expression.

RESULTS

The essential oil was capable of modulating all of the oxidative stress, antioxidant, and anti-inflammatory parameters induced by CLP as characterized by elevations in MPO and MDA levels as well as increases in AST and ALT concentrations concomitant with PGE2 and COX-2 increments. The antioxidant defense system such as GSH and FRAP was also increased in the essential oil treated groups.

CONCLUSION

Our results showed that the essential oil has antioxidative and hepatoprotective activities through reducing the oxidative injury in sepsis caused by CLP.

Assessing the effect of Mentha longifolia essential oils on COX-2 expression in animal model of sepsis induced by caecal ligation and puncture

CONTEXT

Mentha longifolia L. (Lamiaceae), a traditional Iranian plant, possesses antimicrobial and antioxidant activities.

OBJECTIVE

We investigated the potential protective effects of M. longifolia essential oils (E.Os) on caecal ligation and puncture (CLP) induced liver injury.

MATERIALS AND METHODS

Wistar Albino rats (n = 50) were grouped as follows: (1) a laparotomy group (LAP); (2) a CLP group (CLP); (3) the treatment groups received orally the E.Os (50 and 100 mg/kg b.w) and indomethacin (2 mg/kg b.w) for 2 weeks. The oxidative stress parameters, liver enzymes and prostaglandin E2 (PGE2) level were measured in liver and plasma tissues. The liver was also harvested for the real time PCR of cyclooxygenase (COX-2) expression following histopathological examinations.

RESULTS

The results indicated that the CLP operation significantly increased lipid peroxidation (LP) [1.79-fold], myeloperoxidase (MPO) [2.76-fold], PGE2 [1.56-fold] besides plasma aspartate aminotransferase (AST) [2.4-fold] and alanine aminotransferase (ALT) activities [2.22-fold], while, markedly reduced glutathione (GSH) [0.63-fold] and ferric reducing ability of plasma (FRAP) levels [0.63-fold]. Even COX2 expression significantly increased in the CLP group as compared to the LAP group. Treatments of rats with the E.Os could return all the hepatic and plasma biomarkers to the normal levels. These results were further confirmed by pathological examination on liver indicating that E.Os could successfully improve the CLP-induced liver injuries.

DISCUSSION AND CONCLUSIONS

Our findings suggest that E.Os is able to protect liver injuries against sepsis via modulating the oxidative stress parameters concomitant with the suppression of inflammatory reactions such as PGE2 and COX-2.

Role of N-Acetylcysteine and Coenzyme Q10 in the Amelioration of Myocardial Energy Expenditure and Oxidative Stress, Induced by Carbon Tetrachloride Intoxication in Rats

This study is designed to evaluate the potential impact of N-acetyl cysteine (NAC) and coenzyme Q10 (CoQ10) each alone or in combination against carbon tetrachloride (CCl4)-induced cardiac damage in rats. Animals were treated with CCl4 in single intraperitoneal dose of 1 mL/Kg body weight; CCl4-intoxicated animals were pretreated with 20 mg/kg/d NAC or pretreated with 200 mg/kg/d CoQ10 or NAC and CoQ10 with the same previously mentioned doses. Carbon tetrachloride-intoxicated rats showed a significant elevation in nitric oxide and lipid peroxides and downregulation in reduced glutathione level and calcium adenosine triphosphatase. Cardiac glycolytic enzymes levels such as lactate dehydrogenase, phosphofructokinase, and hexokinase were declined coupled with a reduction in glucose content after CCl4 treatment. Moreover, myocardial hydroxyproline level was significantly increased after CCl4-treatment indicating accumulation of interstitial collagen. N-acetyl cysteine and/or CoQ10 effectively alleviated the disturbances in myocardial oxidative stress and antioxidant markers. These antioxidants effectively upregulated the reduction in cardiac energetic biomarkers due to CCl4 treatment. N-acetyl cysteine and/or CoQ10 significantly decreased hydroxyproline level compared to that of CCl4-treated rats. The current data showed that the aforementioned antioxidants have a remarkable cardioprotective effect, suggesting that they may be useful as prophylactic agents against the detrimental effects of cardiotoxins.

Modulation of reactive oxygen species production, apoptosis and cell cycle in pleural exudate cells of carrageenan-induced acute inflammation in rats by rutin

The present study seeks to investigate the effect of rutin, a flavonoid compound in rat models of acute inflammation induced by carrageenan (CAR). Twenty-four female Wistar rats weighing 222-247 g received saline or 2% λ-carrageenan in the pleural cavity and treatment with rutin (80 mg kg^-1) or saline by oral gavage for 21 days prior to the intrapleural induction of CAR. After 4 h of induction, the rats were euthanized, the plasma was prepared from the blood for the analysis of haematological parameters and the pleural exudate was obtained for the analysis of the total cell count, cell viability, reactive oxygen species (ROS) production, apoptosis and cell cycle. The result revealed that rutin exhibited anti-inflammatory effects by modulating the ROS level, apoptosis and cell cycle. This study indicates that rutin may exert a protective effect against ROS-mediated oxidative damage associated with an anti-inflammatory activity in rat models of acute inflammation.

Anti-IL-8 antibody potentiates the effect of exogenous surfactant in respiratory failure caused by meconium aspiration

AIM

Meconium aspiration syndrome (MAS) is life-threatening respiratory failure of newborns which can be treated by exogenous surfactant. In response to meconium, increased levels of chemokine IL-8 (CXCL8) stimulate massive neutrophil infiltration of the lungs. Local accumulation and activation of neutrophils, on-going inflammation, lung edema, and oxidative damage contribute to inactivation of endogenous and therapeutically given surfactants. Therefore, we have hypothesized that addition of monoclonal anti-IL-8 antibody into exogenous surfactant can mitigate the neutrophil-induced local injury and the secondary surfactant inactivation and may finally result in improvement of respiratory functions.

METHODS

New Zealand rabbits with intratracheal meconium-induced respiratory failure (meconium 25 mg/ml, 4 ml/kg) were divided into three groups: untreated (M), surfactant-treated (M + S), and treated with combination of surfactant and anti-IL-8 antibody (M + S + anti-IL-8). Surfactant therapy consisted of two lung lavages with diluted porcine surfactant Curosurf (10 ml/kg, 5 mg phospholipids (PL)/ml) followed by undiluted Curosurf (100 mg PL/kg) delivered by means of asymmetric high-frequency jet ventilation (f. 300/min, Ti 20%). In M + S + anti-IL-8 group, anti-IL-8 antibody (100 µg/kg) was added directly to Curosurf dose. Animals were oxygen-ventilated for additional 5 h, respiratory parameters were measured regularly. Subsequently, cell counts in bronchoalveolar lavage fluid (BAL), lung edema formation, oxidative damage, levels of interleukins (IL)-1β and IL-6 in the lung homogenate were evaluated.

RESULTS

Surfactant instillation significantly improved lung function. Addition of anti-IL-8 to surfactant further improved gas exchange and ventilation efficiency and had longer-lasting effect than surfactant-only therapy. Combined treatment showed the trend to reduce neutrophil count in BAL fluid, local oxidative damage, and levels of IL-1β and IL-6 more effectively than surfactant-alone, however, these differences were not significant.

CONCLUSION

Addition of anti-IL-8 antibody to surfactant could potentiate the efficacy of Curosurf on the gas exchange in experimental model of MAS.

Fine chalk dust induces inflammatory response via p38 and ERK MAPK pathway in rat lung

Chalk teaching is widely used in the world due to low cost, especially in some developing countries. During teaching with chalks, a large amount of fine chalk dust is produced. Although exposure to chalk dust is associated with respiratory diseases, the mechanism underlying the correlation between chalk dust exposure and adverse effects has not fully been elucidated. In this study, inflammation and its signal pathway in rat lungs exposed to fine chalk dust were examined through histopathology analyses; pro-inflammatory gene transcription; and protein levels measured by HE staining, RT-PCR, and western blot analysis. The results demonstrated that fine chalk dust increased neutrophils and up-regulated inflammatory gene mRNA levels (TNF-α, IL-6, TGF-β1, iNOS, and ICAM-1), and oxidative stress marker (HO-1) level, leading to the increase of inflammatory cell infiltration and inflammatory injury on the lungs. These inflammation responses were mediated, at least in part, via p38 and extracellular regulated proteinase (ERK) mitogen-activated protein kinase (MAPK) signaling mechanisms. In contrast, N-acetyl-L-cysteine (NAC) supplement significantly ameliorated these changes in inflammatory responses. Our results support the hypothesis that fine chalk dust can damage rat lungs and the NAC supplement may attenuate fine chalk dust-associated lung inflammation.

κ-Carrageenan Enhances Lipopolysaccharide-Induced Interleukin-8 Secretion by Stimulating the Bcl10-NF-κB Pathway in HT-29 Cells and Aggravates C. freundii-Induced Inflammation in Mice

Background. The dietary usage of carrageenan as common food additive has increased observably over the last 50 years. But there is substantial controversy about its safety. Methods. We investigated whether the κ-carrageenan could enhance lipopolysaccharide-induced IL-8 expression by studying its actions on the TLR4-NF-κB pathway. The aggravating effect of κ-carrageenan on Citrobacter freundii DBS100-induced intestinal inflammation was also investigated in a mouse model. Results. Our data show that κ-carrageenan pretreatment promoted LPS-induced IL-8 expression in HT-29 cells. Although CD14, MD-2, and TLR4 were upregulated, the binding of LPS was not enhanced. However, the pathway of Bcl10-NF-κB was triggered. Interestingly, κ-carrageenan competitively blocked the binding of FITC-LPS. Furthermore, pretreatment with κ-carrageenan for one week previous to gavage with C. freundii DBS100 markedly aggravated weight loss, mortality, and colonic damage. The secretion of cytokines was unbalanced and the ratio of Tregs was decreased significantly. In addition, κ-carrageenan, together with C. freundii DBS100, enhanced the transcription and secretion of TLR4 and NF-κB. Conclusions. κ-Carrageenan can synergistically activate LPS-induced inflammatory through the Bcl10-NF-κB pathway, as indicated by its aggravation of C. freundii DBS100-induced colitis in mice. General Significance. Our results suggest that κ-carrageenan serves as a potential inflammatory agent that magnifies existing intestinal inflammation.

A Review on Various Uses of N-Acetyl Cysteine

N-acetyl cysteine (NAC), as a nutritional supplement, is a greatly applied antioxidant in vivo and in vitro. NAC is a precursor of L-cysteine that results in glutathione elevation biosynthesis. It acts directly as a scavenger of free radicals, especially oxygen radicals. NAC is a powerful antioxidant. It is also recommended as a potential treatment option for different disorders resulted from generation of free oxygen radicals. Additionally, it is a protected and endured mucolytic drug that mellows tenacious mucous discharges. It has been used for treatment of various diseases in a direct action or in a combination with some other medications. This paper presents a review on various applications of NAC in treatment of several diseases.

Beneficial Effects of Trillium govanianum Rhizomes in Pain and Inflammation

Trillium govanianum rhizome is used as an analgesic and anti-inflammatory remedy in traditional medicine in northern Pakistan. In an attempt to establish its medicinal value, the present research evaluated the analgesic and anti-inflammatory potential of T. govanianum. The in vivo anti-inflammatory activity of extract and fractions was investigated in the carrageenan induced paw edema assay. The in vitro suppression of oxidative burst of extract, fractions and isolated compounds was assessed through luminol-enhanced chemiluminescence assay. The in vivo analgesic activity was assayed in chemical and thermal induced nociceptive pain models. The crude methanol extract and its solvent fractions showed anti-inflammatory and analgesic responses, exhibited by significant amelioration of paw edema and relieve of the tonic visceral chemical and acute phasic thermal nociception. In the oxidative burst assay, based on IC₅₀, the crude methanol extract and n-butanol soluble fraction produced a significant inhibition, followed by chloroform and hexane soluble fractions as compared to ibuprofen. Similarly, the isolated compounds pennogenin and borassoside E exhibited significant level of oxidative burst suppressive activity. The in vivo anti-inflammatory and analgesic activities as well as the in vitro inhibition of oxidative burst validated the traditional use of T. govanianum rhizomes as a phytotherapeutic remedy for both inflammatory conditions and pain. The observed activities might be attributed to the presence of steroids and steroid-based compounds. Therefore, the rhizomes of this plant species could serve as potential novel source of compounds effective for alleviating pain and inflammation.

Role of histamine H4 receptor ligands in bleomycin-induced pulmonary fibrosis

Fibrosis of lung tissue is a disease where a chronic inflammatory process determines a pathological remodelling of lung parenchyma. The animal model obtained by intra-tracheal administration of bleomycin in C57BL/6 mice is one of the most validated murine model. Bleomycin stimulates oxidative stress and the production of pro-inflammatory mediators. Histamine H4R have recently been implicated in inflammation and immune diseases. This study was focused to investigate the effects of H4R ligands in the modulation of inflammation and in the reduction of lung fibrosis in C57BL/6 mice treated with bleomycin. C57BL/6 mice were treated with vehicle, JNJ7777120 (JNJ, selective H4R antagonist) or ST-1006 (partial H4R agonist), ST-994 (H4R neutral antagonist) and ST-1012 (inverse H4R agonist) at equimolar doses, released by micro-osmotic pumps for 21days. Airway resistance to inflation was assayed and lung samples were processed to measure malondialdehyde (TBARS); 8-hydroxy-2'-deoxyguanosine (8OHdG); myeloperoxidase (MPO); COX-2 expression and activity as markers of oxidative stress and inflammation. Fibrosis and airway remodelling were evaluated throughout transforming growth factor-β (TGF-β), percentage of positive Goblet cells, smooth muscle layer thickness determination. Our results indicated that JNJ, ST-994 and ST-1012 decreased inflammation and oxidative stress markers, i.e. the number of infiltrating leukocytes evaluated as lung tissue MPO, COX-2 expression and activity, TBARS and 8OHdG production. They also reduced the level of TGF-β, a pro-fibrotic cytokine, collagen deposition, thickness of smooth muscle layer, Goblet cells hyperplasia; resulting in a decrease of airway functional impairment. The results here reported clearly demonstrated that H4R ligands have a beneficial effect in a model of lung fibrosis in the mouse, thus indicating that H4R antagonists or inverse agonists could be a novel therapeutic strategy for lung inflammatory diseases.

Design and Synthesis of N-Arylphthalimides as Inhibitors of Glucocorticoid-Induced TNF Receptor-Related Protein, Proinflammatory Mediators, and Cytokines in Carrageenan-Induced Lung Inflammation

N-Arylphthalimides (1-10P) derived from thalidomide by insertion of hydrophobic groups were evaluated for anti-inflammatory activity, and (4-(1,3-dioxo-1,3-dihydro-2H-isoindol-2-yl)-N'-[(4-ethoxyphenyl)methylidene]benzohydrazide 6P was identified as a promising anti-inflammatory agent. Further testing confirmed that compared with the control, 6P treatment resulted in a considerable decrease in CD4(+), NF-κB p65(+), TNF-α(+), IL-6(+), GITR(+), and IL-17(+) cell populations and an increase in the Foxp3(+), CD4(+)Foxp3(+), and IκBα(+) populations in whole blood and pleural fluid of a mouse model of lung inflammation. Moreover, treatment with compound 6P decreased the proteins associated with inflammation including TNF-α, IL-6, IL-17, GITR, NF-κB, COX-2, STAT-3, and iNOS and increased the anti-inflammatory mediators such as IL-10 and IL-4. Further, histopathological examination confirmed the potent anti-inflammatory effects of compound 6P. Thus, the N-arylphthalimide derivative 6P acts as a potent anti-inflammatory agent in the carrageenan-induced lung inflammation model, suggesting that this compound may be useful for the treatment of inflammation in a clinical setting.

N-acetylcysteine advancement of surfactant therapy in experimental meconium aspiration syndrome: possible mechanisms

Meconium aspiration syndrome (MAS) is meconium-induced respiratory failure of newborns associated with activation of inflammatory and oxidative pathways. For severe MAS, exogenous surfactant treatment is used which improves respiratory functions but does not treat the inflammation. Oxidative process can lead to later surfactant inactivation; hence, surfactant combination with antioxidative agent may enhance the therapeutic effect. Young New Zealand rabbits were instilled by meconium suspension and treated by surfactant alone, N-acetylcysteine (NAC) alone or by their combination and oxygen-ventilated for 5 h. Blood samples were taken before and 30 min after meconium application and 30 min, 1, 3 and 5 h after the treatment for evaluating of oxidative damage, total leukocyte count, leukocyte differential count and respiratory parameters. Leukocyte differential was assessed also in bronchoalveolar lavage fluid. NAC alone had only mild therapeutic effect on MAS. However, the combination of NAC and surfactant facilitated rapid onset of therapeutic effect in respiratory parameters (oxygenation index, PaO(2)/FiO(2)) compared to surfactant alone and was the only treatment which prevented neutrophil migration into the lungs, oxidative damage and lung edema. Moreover, NAC suppressed IL-8 and IL-beta formation and thus seems to be favorable agent for improving surfactant therapy in MAS.

Gold nanoparticles and/or N-acetylcysteine mediate carrageenan-induced inflammation and oxidative stress in a concentration-dependent manner

We report the effect of gold nanoparticles (AuNP) in an acute inflammation model induced by carrageenan (CG) and compared this effect with those induced by the antioxidant N-acetylcysteine (NAC) alone and by the synergistic effect of NAC and AuNP together. Male Wistar rats received saline or saline containing CG administered into the pleural cavity, and some rats also received NAC (20 mg/kg) subcutaneously and/or AuNP administered into the pleural cavity immediately after surgery. Four hours later, the rats were sacrificed and pleural exudates obtained for evaluation of cytokine levels and myeloperoxidase activities. Oxidative stress parameters were also evaluated in the lungs. The results demonstrated that the inflammatory process caused by the administration of CG into the pleural cavity resulted in a substantial increase in the levels of tumor necrosis factor-α, interleukin-1β, and myeloperoxidase and a reduction in interleukin-10 levels. These levels seem to be reversed after different treatments in animals. Antioxidant enzymes exhibited positive responses after treatment of NAC + AuNP, and all treatments were effective at reducing lipid peroxidation and oxidation of thiol groups induced by CG. These findings suggest that small compounds, such as NAC plus AuNP, may be useful in the treatment of conditions associated with local inflammation.

Ameliorative effect of N-acetyl cysteine on alpha-cypermethrin-induced pulmonary toxicity in male rats

Alpha-cypermethrin (α-CYP) is one of the most widely used insecticides. It may become an air pollutant and adversely affect the health. The present study was designed to determine whether treatment with N-acetyl cysteine (NAC), a well-known antioxidant, can be useful for the management of the deleterious effects of α-CYP on lung tissues. For this purpose, thirty two male rats were divided into four different groups (eight rats for each). Group (I) gavaged with corn oil (control group), group (II) gavaged daily with NAC (150 mg kg(-1) body weight), group (III) gavaged with α-CYP (14.5 mg kg(-1) body weight/day, dissolved in corn oil), group (IV) gavaged with NAC then with α-CYP 2 h later for 12 weeks. α-CYP significantly increased serum lactate dehydrogenase (LDH) and pulmonary malondialdehyde (MDA) levels, while decreased the activities of catalase (CAT) and superoxide dismutase (SOD) as well as reduced glutathione (GSH) content in lung. It also provoked higher levels of serum nitric oxide (NO), lung interleukin-1 beta (IL-1β), tumor necrosis factor-alpha (TNF-α), hydroxyproline (Hyp) as well as heme oxygenase-1 (HO-1), inducible nitric oxide synthase (iNOS) and nuclear factor-kappa B (NF-К B) gene expression in lung tissues. Histopathological alterations in lung with congestion, cellular infiltration, necrotic changes and thickening of inter-alveolar septa were observed following α-CYP administration. NAC reduced the adverse effects of α-CYP on lung tissues and improved the histological architecture of lung since it showed antioxidant, anti-inflammatory and antifibrotic effects on lung tissues. Our results indicate that NAC exerts a potent protective effect against α-CYP-induced oxidative damage and inflammation in lung tissues.

Protective effects of N-acetylcysteine on acetic acid-induced colitis in a porcine model

Background

Ulcerative colitis is a chronic inflammatory disease and involves multiple etiological factors. Acetic acid (AA)-induced colitis is a reproducible and simple model, sharing many characteristics with human colitis. N-acetylcysteine (NAC) has been widely used as an antioxidant in vivo and in vitro. NAC can affect several signaling pathways involving in apoptosis, angiogenesis, cell growth and arrest, redox-regulated gene expression, and inflammatory response. Therefore, NAC may not only protect against the direct injurious effects of oxidants, but also beneficially alter inflammatory events in colitis. This study was conducted to investigate whether NAC could alleviate the AA-induced colitis in a porcine model.

Methods

Weaned piglets were used to investigate the effects of NAC on AA-induced colitis. Severity of colitis was evaluated by colon histomorphology measurements, histopathology scores, tissue myeloperoxidase activity, as well as concentrations of malondialdehyde and pro-inflammatory mediators in the plasma and colon. The protective role of NAC was assessed by measurements of antioxidant status, growth modulator, cell apoptosis, and tight junction proteins. Abundances of caspase-3 and claudin-1 proteins in colonic mucosae were determined by the Western blot method. Epidermal growth factor receptor, amphiregulin, tumor necrosis factor-alpha (TNF-α), and toll-like receptor 4 (TLR4) mRNA levels in colonic mucosae were quantified using the real-time fluorescent quantitative PCR.

Results

Compared with the control group, AA treatment increased (P < 0.05) the histopathology scores, intraepithelial lymphocyte (IEL) numbers and density in the colon, myeloperoxidase activity, the concentrations of malondialdehyde and pro-inflammatory mediators in the plasma and colon, while reducing (P < 0.05) goblet cell numbers and the protein/DNA ratio in the colonic mucosa. These adverse effects of AA were partially ameliorated (P < 0.05) by dietary supplementation with NAC. In addition, NAC prevented the AA-induced increase in caspase-3 protein, while stimulating claudin-1 protein expression in the colonic mucosa. Moreover, NAC enhanced mRNA levels for epidermal growth factor and amphiregulin in the colonic mucosa.

Conclusion

Dietary supplementation with NAC can alleviate AA-induced colitis in a porcine model through regulating anti-oxidative responses, cell apoptosis, and EGF gene expression.

Heparin/N-acetylcysteine: an adjuvant in the management of burn inhalation injury: a study of different doses

PURPOSE

Nebulized heparin may reduce fibrin cast formation and reduce the degree of airway obstruction in burn inhalation injury.

METHODS

Twenty-nine patients admitted to burn intensive care unit (ICU) within 24 hours of burn inhalation injury were included in this prospective double-blinded randomized study. Group H5 received nebulized heparin sulfate 5,000 IU, and group H10 received nebulized heparin sulfate 10,000 IU. Heparin was given in alternation with N-acetylcysteine every 2 hours. Lung injury score assessed daily for 7 days was the primary outcome. Duration of mechanical ventilation, coagulation profile, length of ICU stay, and mortality were the secondary outcomes.

RESULTS

Median lung injury scores were significantly lower in group H10 on days 5 (1.9 vs 1), 6 (1.4 vs 0.5), and 7 (1.3 vs 0.5). Group H10 had also a lower duration of mechanical ventilation than did group H5 (P = .037). The groups had no significant difference in coagulation parameters, length of ICU stay (P = .17), and mortality (P = .6).

CONCLUSIONS

Nebulized heparin 10,000 IU decreased lung injury scores and duration of mechanical ventilation but had no effect on length of ICU stay and mortality. Moreover, nebulized heparin 10,000 IU was safe and had no effect on coagulation parameters.

Analgesic and Anti-Inflammatory Activities ofTorenia concolorLindley var.formosanaYamazaki and Betulin in Mice

The present study was intended to examine the analgesic effect of the 70% methanol extract of Torenia concolor Lindley var. formosana Yamazaki (TCMeOH) and betulin using models of acetic acid-induced writhing response and formalin test. In addition, we investigated the anti-inflammatory effect of TCMeOHand betulin using model of λ-carrageenan-induced paw edema. We observed the activities of antioxidant enzymes (SOD, GPx and GR) in the liver and the levels of malondialdehyde (MDA) and nitric oxide (NO) in the edema paw. The results showed that TCMeOH(1.0 and 2.0 g/kg) and betulin (30 and 90 mg/kg), significantly inhibited the acetic acid-induced writhing response. TCMeOH(2.0 g/kg) and betulin (30 and 90 mg/kg) significantly inhibited formalin-induced licking time during both the early and late phases. TCMeOH(0.5, 1.0 and 2.0 g/kg) and betulin (30 and 90 mg/kg) also significantly decreased the paw edema at the 4th hour after λ-carrageenan injection. Furthermore, TCMeOHand betulin treatment also significantly increased the activities of SOD, GR and GPx in the liver while decreasing the level of MDA in the edema paw. Finally, betulin (30 and 90 mg/kg) also caused considerable reduction of NO level in the edema paw. Taken together, the present results indicated that TCMeOHand betulin possessed analgesic and anti-inflammatory effects. The anti-inflammatory mechanism of TCMeOHand betulin may be related to decreasing the levels of MDA and NO in the edema paw by increasing the activities of antioxidant enzymes in the liver.

Anti-inflammation effects of hydrogen saline in LPS activated macrophages and carrageenan induced paw oedema

Background

Oxidative stress is thought to play an important role in the pathogenesis of inflammation. Recent studies have found that hydrogen gas has the effect of eliminating free radicals. Whether hydrogen saline (more convenient to be used than hydrogen gas) has the anti-inflammation effect or not is still unknown.

Methods

Carrageenan-induced paw oedema and LPS-activated macrophages are studied in this article. Injection of carrageenan into the foot of a mouse elicited an acute inflammatory response characterized by increase of foot volume and infiltration of neutrophils. While tumor necrosis factorα(TNF-α) secreted by activated macrophages was determined by ELISA and real-time PCR.

Results

All parameters of inflammation (foot volume, infiltration of neutrophils, amount of TNF-α and the level of TNF-α's mRNA) were attenuated by the hydrogen saline treatment.

Conclusion

As a more convenient way than inhaling H₂, hydrogen saline exhibits a protective effect against inflammation and it might provide a novel therapeutic approach for inflammatory diseases.

Sildenafil treatment attenuates lung and kidney injury due to overproduction of oxidant activity in a rat model of sepsis: a biochemical and histopathological study

Sepsis is a systemic inflammatory response to infection and a major cause of morbidity and mortality. Sildenafil (SLD) is a selective and potent inhibitor of cyclic guanosine monophosphate (cGMP)-specific phosphodiesterase PDE5. We aimed to investigate the protective effects of sildenafil on caecal ligation and puncture (CLP)-induced sepsis in rats. Four groups of rats were used, each composed of 10 rats: (i) 10 mg/kg SLD-treated CLP group; (ii) 20 mg/kg SLD-treated CLP group; (iii) CLP group; and (iv) sham-operated control group. A CLP polymicrobial sepsis model was applied to the rats. All groups were killed 16 h later, and lung, kidney and blood samples were analysed histopathologically and biochemically. Sildenafil increased glutathione (GSH) and decreased the activation of myeloperoxidase (MPO) and of lipid peroxidase (LPO) and levels of superoxide dismutase (SOD) in the septic rats. We observed a significant decrease in LPO and MPO and a decrease in SOD activity in the sildenafil-treated CLP rats compared with the sham group. In addition, 20 mg/kg sildenafil treatment in the sham-operated rats improved the biochemical status of lungs and kidneys. Histopathological analysis revealed significant differences in inflammation scores between the sepsis group and the other groups, except the CLP + sildenafil 10 mg/kg group. The CLP + sildenafil 20 mg/kg group had the lowest inflammation score. Sildenafil treatment decreased the serum tumour necrosis factor (TNF)-α level when compared to the CLP group. Our results indicate that sildenafil is a highly protective agent in preventing lung and kidney damage caused by CLP-induced sepsis via maintenance of the oxidant-anti-oxidant status and decrease in the level of TNF-α.

N-Acetylcysteine prevents baker's-yeast-induced inflammation and fever

OBJECTIVE AND DESIGN

To investigate whether N-acetylcysteine (NAC) alters baker's-yeast-induced fever and inflammation.

MATERIAL OR SUBJECTS

Male Wistar rats (26-28 days old) injected with baker's yeast (135 mg/kg, intraperitoneal) or prostaglandin E(2) (300 ng/100 μL, intrathecal).

TREATMENT

Rats were injected with NAC (500 mg/kg, subcutaneous, or 50 μg/100 μL, intrathecal) 1 h before, or 2 h after, pyrogen injection.

METHODS

Rectal temperature changes induced by baker's yeast, PGE(2) and NAC were followed up over time. Four hours after baker's yeast injection, total leukocytes, protein, interleukin (IL)-1β, tumor necrosis factor (TNF)-α and nonprotein thiol content were assessed in peritoneal lavage and hypothalamus.

RESULTS

Systemic administration of NAC decreased leukocytes, protein, IL-1β and TNF-α levels in peritoneal lavage, and decreased IL-1β levels in the hypothalamus. The central administration of NAC prevented baker's-yeast-induced fever, but did not alter the febrile response elicited by prostaglandin E(2).

CONCLUSION

These results suggest an anti-inflammatory and antipyretic role for NAC in yeast-induced peritonitis.

Hypercholesterolemia and oxidative stress inhibit endothelial cell healing after arterial injury

OBJECTIVE

Endothelial cell (EC) migration is essential for arterial healing after angioplasty. Oxidized low-density lipoproteins and oxidative stress decrease EC migration in vitro. The objective of this study was to determine the effect of hypercholesterolemia and oxidative stress on EC healing after an arterial injury.

METHODS

C57BL/6 wild-type mice were placed in one of eight groups: chow diet (n = 11), high-cholesterol (HC) diet (n = 11), chow diet plus paraquat (n = 11), HC diet plus paraquat (n = 11), chow diet plus N-acetylcysteine (NAC) (n = 11), HC diet plus NAC (n = 11), chow diet plus paraquat and NAC (n = 11), and HC diet plus paraquat and NAC (n = 11). After 2 weeks on the assigned diet with or without NAC, the carotid artery was injured using electrocautery. Animals in the paraquat groups were given 1 mg/kg intraperitoneally to increase oxidative stress. After 120 hours, Evans Blue dye was infused intravenously to stain the area of the artery that remained deendothelialized. This was used to calculate the percentage of re-endothelialization. Plasma and tissue samples were analyzed for measures of oxidative stress.

RESULTS

The HC diet increased oxidative stress and reduced EC healing compared with a chow diet, with EC covering 26.8% ± 2.8% and 48.1% ± 5.2% (P < .001) of the injured area, respectively. Administration of paraquat decreased healing in both chow and HC animals to 18.1% ± 3.5% (P < .001) and 9.8% ± 4.6% (P < .001), respectively. Pretreatment with NAC (120 mmol/L in drinking water) for 2 weeks prior to injury, to decrease oxidative stress, improved EC healing to 39.9% ± 5.7% (P < .001) in hypercholesterolemic mice and to 30.7% ± 3.6% (P < .001) in the paraquat group. NAC treatment improved healing to 24.6% ± 3.4% (P < .001) in hypercholesterolemic mice treated with paraquat.

CONCLUSION

Re-endothelialization of arterial injuries is reduced in hypercholesterolemic mice and is inversely correlated with oxidative stress. An oral antioxidant decreases oxidative stress and improves EC healing.

CLINICAL RELEVANCE

Vascular injury following cardiovascular intervention, including cardiac and peripheral arterial angioplasty and stenting, is associated with inflammation and oxidative stress. Hypercholesterolemia is also associated with increased oxidative stress. Oxidative stress, regardless of the source, induces cellular dysfunction in endothelial and smooth muscle cells that reduce healing after arterial injury. Decreasing oxidative stress with an exogenously administered antioxidant can improve endothelial cell healing, and this is important to control intimal hyperplasia and reduce the thrombogenicity of the vessel.

Role of glutathione in immunity and inflammation in the lung

Reactive oxygen species and thiol antioxidants, including glutathione (GSH), regulate innate immunity at various levels. This review outlines the redox-sensitive steps of the cellular mechanisms implicated in inflammation and host defense against infection, and describes how GSH is not only important as an antioxidant but also as a signaling molecule. There is an extensive literature of the role of GSH in immunity. Most reviews are biased by an oversimplified picture where “bad” free radicals cause all sorts of diseases and “good” antioxidants protect from them and prevent oxidative stress. While this may be the case in certain fields (eg, toxicology), the role of thiols (the topic of this review) in immunity certainly requires wearing scientist’s goggles and being prepared to accept a more complex picture. This review aims at describing the role of GSH in the lung in the context of immunity and inflammation. The first part summarizes the history and basic concepts of this picture. The second part focuses on GSH metabolism/levels in pathology, the third on the role of GSH in innate immunity and inflammation, and the fourth gives 4 examples describing the importance of GSH in the response to infections.

GW0742, a high-affinity PPAR -beta/delta agonist, inhibits acute lung injury in mice

Several lines of evidence suggest a biological role for peroxisome proliferator-activated receptor (PPAR) beta/delta in the pathogenesis of a number of diseases. The aim of this study was to investigate the effects of a high-affinity PPAR-beta/delta agonist, GW0742, in a mouse model of carrageenan (CAR)-induced pleurisy. Injection of CAR into the pleural cavity of mice elicited an acute inflammatory response characterized by accumulation of fluid containing a large number of neutrophils (polymorphonuclear leukocytes) in the pleural cavity, infiltration of polymorphonuclear leukocytes in lung tissues and subsequent lipid peroxidation, and increased production of nitrite/nitrate, TNF-alpha, and IL-1beta. Furthermore, CAR induced lung apoptosis (Bax and Bcl-2 expression), and nitrotyrosine formation was determined by immunohistochemical analysis of lung tissues. Administration of GW0742 (0.3 mg/kg, i.p. bolus) 30 min before and 30 min after a challenge with CAR caused a reduction in all the parameters of inflammation measured. Thus, based on these findings, we propose that a PPAR-beta/delta agonist such as GW0742 may be useful in the treatment of various inflammatory diseases.

In-vivo effects of nociceptin and its structural analogue [Orn9] nociceptin on the antioxidant status of rat blood and liver after carrageenan-induced paw inflammation

The production of reactive oxygen species (ROS) in cells is well balanced with their elimination by the antioxidant defence system. This balance is essential for maintenance of physiological conditions, and its disturbance (oxidative stress) has been suggested as a potential pathogenic mechanism in a variety of diseases, accompanied by inflammation. In this study, the in-vivo effects of nociceptin (N/OFQ(1–13)NH2) and its structure analogue [Orn9]N/OFQ(1–13)NH2 were studied on markers of oxidative stress in erythrocytes and liver of rats 4 hours after subplantar administration of carrageenan (CG) (1%, 100 µl) in the right hind paw. A considerable inflammatory oedema of the paw was observed. CG did not change blood haemoglobin content, hematocrit value, glutathione level and antioxidant enzyme activities in the erythrocytes, but there was an increase in lipid peroxidation. In liver, CG-induced imbalance was manifested by an increase in lipid peroxidation and a decrease in glutathione level. Both peptides (20 µg, i.p.), when administered alone, had no effect on all parameters tested. When either [Orn9]N/OFQ(1–13)NH2 or N/OFQ(1–13)NH2 was injected simultaneously with CG or 15 minutes before it, they did not affect the CG-induced changes in the antioxidant status of the erythrocytes and liver. Our results suggest that the peptides tested did not play a role in the free radical processes that accompany CG-induced paw inflammation.

Antioxidant therapy reverses impaired graft healing in hypercholesterolemic rabbits

OBJECTIVE

Limited endothelial cell (EC) coverage and anastomotic intimal hyperplasia contribute to thrombosis and failure of prosthetic grafts. Lipid accumulation and lipid oxidation are associated with decreased EC migration and intimal hyperplasia. The goal of this study was to assess the ability of antioxidants to improve graft healing in hypercholesterolemic animals.

METHODS

Rabbits were placed in one of four groups: chow plus N-acetylcysteine (NAC), chow plus probucol, chow with 1% cholesterol plus NAC, or chow with 1% cholesterol plus probucol. After 2 weeks, expanded polytetrafluoroethylene grafts (12 cm long x 4-mm internal diameter) were implanted in the abdominal aorta. Grafts were removed after 6 weeks and analyzed for cholesterol content, EC coverage, anastomotic intimal thickness, and the cellular composition of the neointima. Plasma samples were obtained to assess systemic oxidative stress. The data were compared with previously reported data from animals fed diets of chow and chow with 1% cholesterol.

RESULTS

Prosthetic grafts from rabbits fed chow with 1% cholesterol had significantly greater anastomotic intimal thickening and lower EC coverage than grafts from rabbits fed a regular chow diet. In hypercholesterolemic rabbits, antioxidant therapy decreased global oxidative stress as evidenced by a 40% decrease in plasma thiobarbituric acid reactive substances. In rabbits fed the chow with 1% cholesterol diet, NAC decreased intimal hyperplasia at the proximal anastomosis by 29% and significantly increased graft EC coverage from 46% to 71% (P = .03). Following a similar pattern, probucol decreased intimal hyperplasia by 43% and increased graft EC coverage to 53% in hypercholesterolemic rabbits.

CONCLUSIONS

Global oxidative stress and anastomotic intimal hyperplasia are increased, and endothelialization of prosthetic grafts is significantly reduced in rabbits fed a high-cholesterol diet. Antioxidant treatment improves EC coverage and decreases intimal hyperplasia. Reducing oxidative stress may promote healing of prosthetic grafts.

Effect of Zanthoxylum schinifolium on TNF-alpha-induced vascular inflammation in human umbilical vein endothelial cells

Pro-inflammatory cytokines induce the injury of endothelial cells in response to increases of adhesion molecules, leading to vascular inflammation and the development of atherosclerosis. In this study, we evaluated an ethanol extract of Zanthoxylum schinifolium (EZS) to determine if it inhibits the expressions of cellular adhesion molecules in human umbilical vein endothelial cells (HUVEC). When pretreatment of HUVEC with EZS, EZS suppressed the expression levels of cell adhesion molecules such as vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-), and E-selectin induced by TNF-alpha. The adhesion of HL-60 cells to TNF-alpha-induced endothelial cells was decreased significantly in a concentration-dependent manner. Furthermore, TNF-alpha-induced MCP-1 and IL-8 mRNA expression levels were also attenuated by pretreatment with EZS. In addition, EZS suppressed TNF-alpha-induced production of reactive oxygen species (ROS). EZS inhibited NF-kappaB activation and IkappaB-alpha phosphorylation induced by TNF-alpha, subsequent degradation of IkappaB-alpha. Finally, EZS inhibited TNF-alpha-induced p38 MAPK and c-Jun N-terminal kinase (JNK) phosphorylation. Taken together, these results demonstrate that EZS suppresses vascular inflammatory process, which may be closely related to the inhibition of ROS, JNK, p38 MAPK and NF-kappaB activation in HUVEC.

N-acetylcysteine prevents carbon tetrachloride-induced liver cirrhosis: role of liver transforming growth factor-beta and oxidative stress

OBJECTIVES

N-acetylcysteine (NAC) is an antioxidant, a precursor of reduced glutathione, and an inhibitor of the profibrotic cytokine liver transforming growth factor-beta (TGF-beta). Carbon tetrachloride (CCl4) cirrhosis is characterized by oxidative stress and fibrosis. Therefore, the aim of this work was to study the effect of NAC on experimental cirrhosis.

METHODS

CCl4 was chronically administered for 8 weeks along with 300 mg/kg of NAC orally once a day. Alkaline phosphatase, alanine aminotransferase, and gamma-glutamyltranspeptidase were measured in plasma. Hydroxyproline, glycogen, lipid peroxidation, glutathione were determined in liver samples by colorimetric methods. TGF-beta was evaluated by western blotting, and a histopathological analysis was performed.

RESULTS

Serum markers of liver damage increased by CCl4 intoxication (P<0.05), whereas cotreatment with NAC prevented these increases (P<0.05); glycogen was depleted in the cirrhotic group (P<0.05), but preserved by NAC (P<0.05). Lipid peroxidation increased and glutathione decreased by the administration of CCl4 (P<0.05), again NAC prevented both effects (P<0.05). Importantly, collagen increased by about seven-fold in the CCl4 group (P<0.05); administration of NAC preserved the normal levels of collagen (P<0.05). Biochemical determinations were corroborated by hematoxylin and eosin, and trichromic stains. Western blots revealed a four-fold increase in TGF-beta in the group receiving CCl4, NAC cotreatment abolished TGF-beta signal (P<0.05).

CONCLUSION

Our results strongly suggest that NAC prevents experimental cirrhosis by two mechanisms: by preventing oxidative stress and by downregulating the profibrogenic cytokine TGF-beta. As NAC is currently used in humans intoxicated with paracetamol, it can be tested in fibrotic or cirrhotic patients under controlled trials.

EFFECTS OFN-ACETYLCYSTEINE ON OXIDANT-ANTIOXIDANT BALANCE IN OLEIC ACID–INDUCED LUNG INJURY

The antioxidant and anti-inflammatory properties of N-acetylcysteine has been documented in many experimental lung injury models. Because intravenous injection of oleic acid induces histopathologic changes similar to those seen in human acute lung injury or acute respiratory distress syndrome, the authors evaluated the effects of N-acetylcysteine (NAC) on oxidative stress and lung damage in an oleic acid (OA)-induced lung injury model. Thirty-five rats were divided into 5 groups as sham, NAC, OA, pre-OA-NAC, and post-OA-NAC. Lung damage was induced by intravenous administration of oleic acid. Pre-OA-NACgroup received intravenous (IV) N-acetylcysteine 15 minutes before oleic acid infusion and post-OA-NAC group received IV N-acetylcysteine 2 hours after oleic acid infusion. In both of the N-acetylcysteine treatment groups, blood and tissue samples were collected 4 hours after oleic acid infusion, independent from the time of N-acetylcysteine infusion. In other groups, blood and tissue samples were collected 4 hours after ethanol, NAC, or OA infusions. Serum myeloperoxidase activity, total antioxidant capacity, malondialdehyde levels, and lung tissue Na+ - K+ ATPase activity were measured and light microscopic analyses of lung specimens were performed. The administration of N-acetylcysteine significantly restored Na+ - K+ ATPase activity and total antioxidant capacity levels and ameliorated lung architecture. N-acetylcysteine has been shown to have some attenuating effects in experimental animal studies. However, further investigations are necessary to suggest N-acetylcysteine as a treatment agent in critically ill patients with lung injury.

In vivo effects of N/OFQ(1–13)NH2 and its structural analogue [ORN9]N/OFQ(1–13)NH2 on carrageenan-induced inflammation: rat-paw oedema and antioxidant status

The effects of nociceptin(1–13)NH2 (N/OFQ(1–13)NH2) and its structural analogue [Orn9]N/OFQ(1–13)NH2 on acute carrageenan (CG)-induced peripheral inflammation and paw antioxidant status were studied. CG was injected intraplantarly in the right hind paw of rats and the volume of the inflamed paw was measured each 30 min for a period of 4h. When administered simultaneously with CG, N/OFQ(1–13)NH2 decreased the paw volume, whereas if injected 15 min before CG it had no effect. [Orn9]N/OFQ(1–13)NH2 produced the opposite effects at the same time-intervals of its administration. We also investigated whether these neuropeptides influence CG-induced changes in cell antioxidant system, especially at the 4th hour of CG administration. CG alone decreased the glutathione level and superoxide dismutase activity, as measured in post-nuclear homogenate of the inflamed paw. However, CG injection increased glutathione peroxidase and glucose-6-phospate dehydrogenase activities, while the activity of glutathione reductase was unchanged. The peptides themselves did not change all measured parameters. Moreover, neither N/OFQ(1–13)NH2 nor [Orn9]N/OFQ(1–13)NH2 modified CG-induced changes in the antioxidant status, regardless of the time of their injection (simultaneously or 15 min before CG). The present results suggest that N/OFQ(1–13)NH2 and [Orn9]N/OFQ(1–13)NH2 most likely affect the neuronal inflammation, rather than act as pro- or antioxidants.

N-acetyl-L-cysteine inhibits TGF-beta1-induced profibrotic responses in fibroblasts

BACKGROUND

Excessive production of TGF-beta(1) plays a key role in the tissue remodeling or fibrotic process observed in bronchial asthma, chronic pulmonary disease (COPD), and idiopathic pulmonary fibrosis (IPF). TGF-beta(1) has been reported to decrease the intracellular glutathione level and stimulate the production of reactive oxygen species.

OBJECTIVES

The aim of this study was to evaluate whether the antioxidant N-acetyl-l-cysteine (NAC) can affect TGF-beta(1)-mediated tissue remodeling in fibroblasts or modulate the production of fibronectin and vascular endothelial growth factor (VEGF) which are believed to be important mediators of tissue repair and remodeling.

METHODS

To accomplish this, human fetal lung fibroblasts (HFL-1) were used to assess the effect of NAC on the TGF-beta(1)-mediated contraction of floating gels and the TGF-beta(1)-induced mediator production. In addition, the effect of NAC on the TGF-beta(1)-induced differentiation to myofibroblasts was evaluated by assessing alpha-smooth muscle actin (alpha-SMA) expression.

RESULTS

NAC significantly abolished the TGF-beta(1)-augmented gel contraction (at 3mM, gel size 63.4+/-2.6% vs. 39.1+/-4.1%; p<0.01) compared with control in a concentration-dependent manner. NAC also significantly inhibited the TGF-beta(1)-augmented fibronectin (p<0.01) and VEGF (p<0.01) production in the media of both the three-dimensional gel and monolayer culture. Furthermore, NAC reversed the TGF-beta(1)-stimulated alpha-SMA expression (p<0.01).

CONCLUSION

These results suggest that NAC can affect the TGF-beta(1)-induced tissue remodeling or fibrotic process in vitro.

Effect of tumour necrosis factor-alpha receptor 1 genetic deletion on carrageenan-induced acute inflammation: a comparison with etanercept

In the present study, we used tumour necrosis factor-alpha receptor 1 knock-out mice (TNF-alphaR1KO) to evaluate an in vivo role of TNF-alphaR1 on the pathogenesis of inflammatory diseases. We used a murine model of carrageenan-induced acute inflammation (pleurisy), a preclinical model of airway inflammation. The data proved that TNF-alphaR1KO were resistant to carrageenan-induced acute inflammation compared with TNF-alpha wild-type mice. TNF-alphaR1KO showed a significant reduction in accumulation of pleural exudate and in the number of inflammatory cells, in lung infiltration of polymorphonuclear leucocytes and lipid peroxidation and showed a decreased production of nitrite/nitrate in pleural exudates. Furthermore, the intensity and degree of the adhesion molecule intercellular adhesion molecule-1 and P-selectin, Fas ligand (FasL), inducible nitric oxide sythase and nitrotyrosine determined by immunohistochemical analysis were reduced markedly in lung tissues from TNF-alphaR1KO at 4 h and 24 h after carrageenan injection. Moreover, TNF-alpha and interleukin-1beta concentrations were reduced in inflamed areas and in pleural exudates from TNF-alphaR1KO. To support the results generated using pleural inflammation, carrageenan-induced paw oedema models were also performed. In order to elucidate whether the observed anti-inflammatory effects were related to the inhibition of TNF-alpha, we also investigated the effect of etanercept, a TNF-alpha soluble receptor construct, on carrageenan-induced pleurisy. The treatment with etanercept (5 mg/kg subcutaneously 2 h before the carrageenan injection) reduces markedly both laboratory and histological signs of carrageenan-induced pleurisy. Our results showed that administration of etanercept resulted in the same outcome as that of deletion of the TNF-alphaR1 receptor, adding a new insight to TNF-alpha as an excellent target by therapeutic applications.

Piper longum Linn. Extract inhibits TNF-alpha-induced expression of cell adhesion molecules by inhibiting NF-kappaB activation and microsomal lipid peroxidation

Recruitment of specific leukocyte subpopulations at the site of inflammation requires a series of cell adhesion molecule (CAM)-mediated interactions. The major CAMs, viz., intercellular adhesion molecule-1 (ICAM-1), VCAM-1 and E-selectin are expressed on endothelium in response to various cytokines or bacterial LPS. Here, we have evaluated the effect of Piper longum chloroform extract (PlCE) on TNF-alpha-induced expression of ICAM-1 on endothelial cells and on NADPH-catalyzed rat liver microsomal lipid peroxidation with a view to identify modulators for the expression of CAMs. We demonstrate that PlCE inhibits adhesion of neutrophils to endothelial monolayer. This inhibition is due to the ability of PlCE to significantly block the TNF-alpha-induced expression of CAMs, i.e. ICAM-1, VCAM-1 at 17.5 microg/ml concentration and E-selectin at 15 microg/ml concentration on human umbilical vein endothelial cells. The inhibition of ICAM-1, VCAM-1 and E-selectin by PlCE is mediated through inhibition of NF-kappaB in endothelial cells. To demonstrate the antioxidant activity of PlCE, we showed that PlCE inhibited the NADPH-catalyzed rat liver microsomal lipid peroxidation significantly. These results suggest a possible mechanism of anti-inflammatory as well as antioxidant activity of PlCE.

Poly (ADP-ribose) polymerase activation and circulatory shock

Sepsis is associated with increased production of reactive oxidant species. Oxidative and nitrosative stress can lead to activation of the nuclear enzyme poly (ADP-ribose) polymerase (PARP), with subsequent loss of cellular functions. Activation of PARP may dramatically lower the intracellular concentration of its substrate, NAD thus slowing the rate of glycolysis, electron transport and subsequently ATP formation. This process can result in cell dysfunction and cell death. In addition, PARP enhances the expression of various pro-inflammatory mediators, via activation of NF-kappaB, MAP kinase and AP-1 and other signal transduction pathways. Preclinical studies in various rodent and large animal models demonstrate that PARP inhibition or PAR deficiency exerts beneficial effects on the haemodynamic and metabolic alterations associated with septic and haemorrhagic shock. Recent human data also support the role of PARP in septic shock: In a retrospective study in 25 septic patients, an increase in plasma troponin level was related to increased mortality risk. In patients who died, significant myocardial damage was detected, and histological analysis of heart showed inflammatory infiltration, increased collagen deposition, and derangement of mitochondrial criptae. Immunohistochemical staining for poly(ADP-ribose) (PAR), the product of activated PARP was demonstrated in septic hearts. There was a positive correlation between PAR staining and troponin I; and a correlation of PAR staining and LVSSW. Thus, there is significant PARP activation in animal models subjected to circulatory shock, as well as in the hearts of septic patients. Based on the interventional studies in animals and the correlations observed in patients we propose that PARP activation may be, in part responsible for the cardiac depression and haemodynamic failure seen in humans with severe sepsis. Interestingly, recent studies reveal that the protective effects of PARP inhibitors are predominant in male animals, and are not apparent in female animals. Oestrogen, by providing a baseline inhibitory effect on PARP activation, may be partially responsible for this gender difference.

Formation and role of plasma S-nitrosothiols in liver ischemia-reperfusion injury

Plasma S-nitrosothiols (RSNOs) may act as a circulating form of nitric oxide that affects vascular function and platelet aggregation. Their role in liver ischemia/reperfusion (I/R) injury is largely unknown. The aim of the present study was to investigate the changes in plasma RSNOs following liver I/R injury. Two groups of New Zealand white rabbits were used (n=6, each): the I/R group underwent 60 min lobar liver ischemia and 7 h reperfusion, while the sham group underwent laparotomy but no liver ischemia. Serial RSNO levels were measured in plasma by electron paramagnetic resonance (EPR) spectrometry, nitrite/nitrates by capillary electrophoresis, hepatic microcirculation by laser Doppler flowmetry, redox state of hepatic cytochrome oxidase by near-infrared spectroscopy, liver iNOS mRNA expression by reverse transcription-polymerase chain reaction (RT-PCR) and the oxidation of dihydrorhodamine to rhodamine by fluorescence. The effect of the antioxidant N-acetylcysteine (NAC) on RSNOs formation and DHR oxidation was tested in a third group of animals (n=6) undergoing lobar liver I/R. Hepatic I/R was associated with a significant increase in plasma RSNOs, plasma nitrites, hepatic iNOS mRNA expression, impairment in hepatic microcirculation, decrease in the redox state of cytochrome oxidase, and significant production of rhodamine. The changes were more obvious during the late phase of reperfusion (>4 h). NAC administration decreased plasma RSNOs and oxidation of DHR to RH (P<0.05, 5 and 7 h postreperfusion, respectively). These results suggest that significant upregulation of nitric oxide synthesis during the late phase of reperfusion is associated with impairment in microcirculation and mitochondrial dysfunction. Plasma S-nitrosothiols are a good marker of this nitric oxide-mediated hepatotoxicity.

Carrageenan induces interleukin-8 production through distinct Bcl10 pathway in normal human colonic epithelial cells

Carrageenan is a high molecular weight sulfated polygalactan used to improve the texture of commercial food products. Its use increased markedly during the last half century, although carrageenan is known to induce inflammation in rheumatological models and in intestinal models of colitis. We performed studies to determine its direct effects on human intestinal cells, including normal human intestinal epithelial cells from colonic surgeries, the normal intestinal epithelial cell line NCM460, and normal rat ileal epithelial cells. Cells were treated with high molecular weight lambda-carrageenan at a concentration of 1 mug/ml for 1-96 h. IL-8, IL-8 promoter activity, total and nuclear NF-kappaB, IkappaBalpha, phospho-IkappaBalpha, and Bcl10 were assessed by immunohistochemistry, Western blot, ELISA, and cDNA microarray. Increased Bcl10, nuclear and cytoplasmic NF-kappaB, IL-8 promoter activation, and IL-8 secretion were detected following carrageenan exposure. Knockdown of Bcl10 by siRNA markedly reduced the increase in IL-8 that followed carrageenan exposure in the NCM460 cells. These results show, for the first time, that exposure of human intestinal epithelial cells to carrageenan triggers a distinct inflammatory pathway via activation of Bcl10 with NF-kappaB activation and upregulation of IL-8 secretion. Since Bcl10 contains a caspase-recruitment domain, similar to that found in NOD2/CARD15 and associated with genetic predisposition to Crohn's disease, the study findings may represent a link between genetic and environmental etiologies of inflammatory bowel disease. Because of the high use of carrageenan as a food additive in the diet, the findings may have clinical significance.

Angiotensin II Stimulates Endothelial Integrin β3Expression via Nuclear Factor-κB Activation

The present study examined the effect and part mechanism of angiotensin II-stimulated integrin beta3 gene expression in human umbilical vein endothelial cells. Protein level and mRNA level of integrin beta3 expression were determined using enzyme-linked immunoadsorbent assay and reverse transcription-polymerase chain reaction. Four plasmids of 5'-different deletion of integrin beta3 gene promoter were constructed to transiently transfected into cells to uncover the region in response to angiotensin II. Blockade of nuclear factor-kappaB (NF-kappaB) signaling pathway effect on integrin beta3 expression was analyzed by cotransfection with mutant plasmids for NF-kappaB-inducing kinase, inhibitory proteins alpha and beta of NF-kappaB kinase, respectively, together with the integrin beta3 plasmid including the sequence -1486 approximately - 900. The study found that 10(-8) mol/L,10(-7) mol/L, 10(-6) mol/L, and 10(-5) mol/L angiotensin II increased integrin beta(3) protein level by 45%, 52%, 62%, and 73% respectively. Angiotensin II at 10(-6) mol/L increased integrin beta3 mRNA level by 67%. The luciferase activity of the integrin beta3 plasmid PGL3 - 1486 approximately - 900 increased by 84.72% in response to angiotensin II. N-acetylcysteine blocked angiotensin II-induced NF-kappaB activity and integrin beta3 expression. Blockade of NF-kappaB signaling pathway abolished the stimulation of angiotensin II. These results suggest that angiotensin II stimulates integrin beta3 expression partly by NF-kappaB activation.

Role of oxidative stress in experimental sepsis and multisystem organ dysfunction

Massive increase in radical species can lead to oxidative stress, promoting cell injury and death. This review focuses on experimental evidence of oxidative stress in critical illnesses, sepsis and multisystem organ dysfunction. Oxidative stress could negatively affect organ injury and thus overall survival of experimental models. Based on this experimental evidence, we could improve the rationale of supplementation of antioxidants alone or in combination with standard therapies aimed to reduce oxidative stress as novel adjunct treatment in critical care.