Effects of nitric oxide synthase inhibition in lipopolysaccharide-induced sepsis in mice

iNOS inhibitor S-methylisothiourea alleviates smoke inhalation-induced acute lung injury by suppressing inflammation and macrophage infiltration

OBJECTIVE

We investigated the effects of the inducible NO synthase (iNOS) inhibitor, S-methylisothiourea (SMT), in a mouse model of smoke inhalation-induced acute lung injury (ALI) and explored the underlying molecular mechanism.

METHODS AND ANALYSIS

A mouse model of smoke inhalation-induced ALI was established. RNA-sequencing (seq) analysis was conducted to identify the differentially expressed genes (DEGs). Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses were performed for functional annotation of DEGs. Moreover, an immunofluorescence assay using macrophage marker F4/80 was performed to assess macrophage infiltration. A hypoxia-induced HUVEC model was used to mimic smoke inhalation-induced injury in endothelial cells. Finally, a transwell assay was used to analyze the chemoattractive effects of endothelial cells on macrophages.

RESULTS

SMT markedly alleviated the pulmonary pathological symptoms, edema, and inflammatory response in the mouse smoke inhalation-induced ALI model. RNA-seq analysis revealed that SMT may diminish lung injury by regulating the levels of genes associated with inflammatory responses, cell chemokines, and adhesion. In vivo data revealed that the protective effects of SMT against smoke inhalation-induced ALI were partly achieved by inhibiting the production of adhesion molecules and infiltration of macrophages. Furthermore, in vitro data from the hypoxia-induced HUVEC model revealed that SMT reduced macrophage chemotaxis by inhibiting the production of chemokines and adhesion molecules in endothelial cells.

CONCLUSION

iNOS inhibitor SMT protects the lungs from smoke inhalation-induced ALI by reducing the production of pro-inflammatory cytokines, adhesion molecules, and chemokines in endothelial cells, thereby inhibiting inflammation and macrophage infiltration.

Elucidations of Molecular Mechanism and Mechanistic Effects of Environmental Toxicants in Neurological Disorders

Due to rising environmental and global public health concerns associated with environmental contamination, human populations are continually being exposed to environmental toxicants, including physical chemical mutagens widespread in our environment causing adverse consequences and inducing a variety of neurological disorders in humans. Physical mutagens comprise ionizing and non-ionizing radiation, such as UV rays, IR rays, X-rays, which produces a broad spectrum of neuronal destruction, including neuroinflammation, genetic instability, enhanced oxidative stress driving mitochondrial damage in the human neuronal antecedent cells, cognitive impairment due to alterations in neuronal function, especially in synaptic plasticity, neurogenesis repression, modifications in mature neuronal networks drives to enhanced neurodegenerative risk. Chemical Mutagens including alkylating agents (EMS, NM, MMS, and NTG), Hydroxylamine, nitrous acid, sodium azide, halouracils are the major toxic mutagen in our environment and have been associated with neurological disorders. These chemical mutagens create dimers of pyrimidine that cause DNA damage that leads to ROS generation producing mutations, chromosomal abnormalities, genotoxicity which leads to increased neurodegenerative risk. The toxicity of four heavy metal including Cd, As, Pb, Hg is mostly responsible for complicated neurological disorders in humans. Cadmium exposure can enhance the permeability of the BBB and penetrate the brain, driving brain intracellular accumulation, cellular dysfunction, and cerebral edema. Arsenic exerts its toxic effect by induction of ROS production in neuronal cells. In this review, we summarize the molecular mechanism and mechanistic effects of mutagens in the environment and their role in multiple neurological disorders.

Two Promising Anti-Cancer Compounds, 2-Hydroxycinnaldehyde and 2-Benzoyloxycinnamaldehyde: Where do we stand?

Natural bioactive compounds with anti-carcinogenic activity are gaining tremendous interest in the field of oncology. Cinnamon, an aromatic condiment commonly used in tropical regions, appeared incredibly promising as adjuvant for cancer therapy. Indeed, its whole or active parts (e.g., bark, leaf) exhibited significant anti-carcinogenic activity, which is mainly due to two cinnamaldehyde derivatives, namely 2-hydroxycinnaldehyde (HCA) and 2-benzoyloxycinnamaldehyde (BCA). In addition to their anti-cancer activity, HCA and BCA exert immunomodulatory, anti-platelets, and anti-inflammatory activities. Highly reactive α,ß-unsaturated carbonyl pharmacophore, called Michael acceptor, contribute to their therapeutic effects. The molecular mechanisms, underlying their anti-tumoral and anti-metastatic effects are miscellaneous, strongly suggesting that these compounds are multi-targeting compounds. Nevertheless, unravelling the exact molecular mechanisms of HCA and BCA remain a challenging matter which is necessary for optimal controlled-drug targeting delivery, safety, and efficiency. Eventually, their poor pharmacological properties (e.g., systemic bioavailability and solubility) represent a limitation, and depend both on their administration route (e.g., per os, intravenously) and the nature of the formulation (e.g., free, smart nano-). This concise review focused on the potential of HCA and BCA as adjuvants in Cancer. We described their medicinal effects as well as provide an update about their molecular mechanisms reported either in-vitro, ex-vivo, or in animal models.

Zingiber cassumunar Roxb. extract increase the reactive oxidant level and interleukins expression in vitro

Zingiber cassumunar Roxb. (bangle) has a variety of active compounds, including curcumin and phenylbutenoid. Bangle rhizoma reported exhibiting immunomodulatory activities. This research aims to determine the mechanism of bangle extract as an immunomodulator by the secretion of Reactive Oxygen Intermediate (ROI), Nitric Oxide (NO), and interleukin (IL-10 and IL-14) expression level. Bangle extract (Zingiber cassumunar Roxb.) was made by the maceration method using 96% ethanol solvent. This research was administered in vitro using macrophage cells from male mice with Balb/C strain divided into 2 groups: normal control and treatment group (receiving 25, 50, and 100 ppm of extract). The administration of bangle extract can function as an immunomodulator by an increase of ROI in 25 and 50 ppm of the extract significantly than the control group (p <0.05), the treatment groups decrease NO level (p <0.05), it also was found to increase expression of IL-10 and IL-14 expression levels (p <0.05). Zingiber cassumunar Roxb. extract was potentially to be developed as an immunomodulator.

Metformin and Probiotics in the Crosstalk between Colitis-Associated Colorectal Cancer and Diabetes in Mice

The co-occurrence of colorectal cancer (CRC) and diabetes mellitus along with inflammation and dismicrobism has been frequently reported. Several studies shed light on the antioncogenic potential of metformin on colorectal carcinogenesis. This study aimed to demonstrate that metformin in association with probiotics acts in a synergic effect in breaking the crosstalk, thus inhibiting CRC progression, improving diabetes, and reducing inflammation. Ninety-six male Balb/c mice, 6–8 weeks old, were divided into 16 control and experimental groups to assess the effect of the different treatments and combinations at the clinical, histological, and molecular levels. Metformin and probiotics showed beneficial outcomes on CRC and diabetes, alone and most importantly in combination. Their effects were exerted by inhibiting the inflammatory process whereby a downregulation of IL-6 and TNF-α as well as oxidative stress were depicted. The characterization of the effects of probiotics and metformin on CRC and diabetes sheds light on the role of inflammation and microbiota in this crosstalk. Deciphering the downstream signaling pathways elicited by these compounds will help in developing new effective targeted treatment modalities.

Phytosterols Suppress Phagocytosis and Inhibit Inflammatory Mediators via ERK Pathway on LPS-Triggered Inflammatory Responses in RAW264.7 Macrophages and the Correlation with Their Structure

Phytosterols, found in many commonly consumed foods, exhibit a broad range of physiological activities including anti-inflammatory effects. In this study, the anti-inflammatory effects of ergosterol, β-sitosterol, stigmasterol, campesterol, and ergosterol acetate were investigated in lipopolysaccharide (LPS)-induced RAW264.7 macrophages. Results showed that all phytosterol compounds alleviated the inflammatory reaction in LPS-induced macrophage models; cell phagocytosis, nitric oxide (NO) production, release of tumor necrosis factor-α (TNF-α), and expression and activity of pro-inflammatory mediator cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS), and phosphorylated extracellular signal-regulated protein kinase (p-ERK) were all inhibited. The anti-inflammatory activity of β-sitosterol was higher than stigmasterol and campesterol, which suggests that phytosterols without a double bond on C-22 and with ethyl on C-24 were more effective. However, inconsistent results were observed upon comparison of ergosterol and ergosterol acetate (hydroxy or ester group on C-3), which suggest that additional research is still needed to ascertain the contribution of structure to their anti-inflammatory effects.

Protective Role of Epigallocatechin Gallate in a Rat Model of Cisplatin-Induced Cerebral Inflammation and Oxidative Damage: Impact of Modulating NF-κB and Nrf2

Cisplatin is a widely used chemotherapeutic agent in treating various types of cancers. However, it can induce neurotoxicity and nephrotoxicity, limiting its dose and clinical use. Although previous studies indicated the direct link between cisplatin-induced central neurotoxicity and oxidative stress, the exact mechanism is not completely understood. Therefore, herein we investigated the effects of prophylactic and concurrent treatment with (-)-epigallocatechin-3-gallate (EGCG), a natural polyphenolic neuroprotective antioxidant, on cisplatin-induced brain toxicity in rats to delineate its molecular mechanism of action. We found that cisplatin initiated a cascade of genetic, biological, and histopathological changes in the brain cortex, inducing inflammatory cytokines, appearance of scattered inflammatory cells, nitro-oxidative stress, and apoptotic proteins in the cerebral cortex. However, EGCG not only protected against cisplatin-induced inflammatory burden but also ameliorated the induction of nitro-oxidative stress and apoptotic proteins triggered by cisplatin in the cerebral cortex of pre- and co-treated rats with respect to their unprotected counterparts. EGCG anti-inflammatory effect here may be attributed to the downregulation of nuclear factor kappa B (NF-κB). Additionally, this natural polyphenol significantly ameliorated cisplatin-elicited reduction in cerebral cortex brain-derived neurotrophic factor and acetylcholine esterase. Upregulation of nuclear factor erythroid 2-related factor 2 (Nrf2) and its downstream heme oxygenase-1 (HO-1) by EGCG prophylactic and concurrent administration here seems also to play a key role in the protective impact of EGCG against cisplatin toxicity through enhancing total antioxidant capacity. Thus, EGCG can be used as a promising prophylactic adjuvant for preventing the development of brain inflammation and oxidative damage associated with cisplatin chemotherapy.

Aminoguanidine affects systemic and lung inflammation induced by lipopolysaccharide in rats

Background

Nitric oxide is a mediator of potential importance in numerous physiological and inflammatory processes in the lung. Aminoguanidine (AG) has been shown to have anti-inflammation and radical scavenging properties. This study aimed to investigate the effects of AG, an iNOS inhibitor, on lipopolysaccharide (LPS)-induced systemic and lung inflammation in rats.

Methods

Male Wistar rats were divided into control, LPS (1 mg/kg/day i.p.), and LPS groups treated with AG 50, 100 or 150 mg/kg/day i.p. for five weeks. Total nitrite concentration, total and differential white blood cells (WBC) count, oxidative stress markers, and the levels of IL-4, IFN-γ, TGF-β1, and PGE2 were assessed in the serum or bronchoalveolar lavage fluid (BALF).

Results

Administration of LPS decreased IL-4 level (p < 0.01) in BALF, total thiol content, superoxide dismutase (SOD) and catalase (CAT) activities (p < 0.001) in BALF and serum, and increased total nitrite, malondialdehyde (MDA), IFN-γ, TGF-β1 and PGE2 (p < 0.001) concentrations in BALF. Pre-treatment with AG increased BALF level of IL-4 and total thiol as well as SOD and CAT activities (p < 0.05 to p < 0.001), but decreased BALF levels of total nitrite, MDA, IFN-γ, TGF-β1, and PGE2 (p < 0.01 to p < 0.001). AG treatment decreased total WBC count, lymphocytes and macrophages in BALF (p < 0.01 to p < 0.001) and improved lung pathological changes including interstitial inflammation and lymphoid infiltration (p < 0.05 to p < 0.001).

Conclusions

AG treatment reduced oxidant markers, inflammatory cytokines and lung pathological changes but increased antioxidants and anti-inflammatory cytokines. Therefore, AG may play a significant protective role against inflammation and oxidative stress that cause lung injury.

Anti-Inflammatory Effects of Catalpalactone Isolated from Catalpa ovata in LPS-Induced RAW264.7 Cells

Catalpa ovata (Bignoniaceae) is widely distributed throughout Korea, China, and Japan. This study investigated the anti-inflammatory effects of catalpalactone isolated from C. ovata in lipopolysaccharide (LPS)-induced RAW264.7 cells. Catalpalactone significantly inhibited nitric oxide (NO) production and inducible NO synthase (iNOS) expression in LPS-induced RAW264.7 cells. The levels of cytokines such as interleukin-6 and tumor necrosis factor-α were reduced under catalpalactone exposure in LPS-induced RAW264.7 cells. Additionally, catalpalactone suppressed signal transducer and activator of transcription 1 (STAT-1) protein expression and interferon-β (IFN-β) production. Treatment with catalpalactone prevented interferon regulatory factor 3 (IRF3) and nuclear factor-κB (NF-κB) activation. Taken together, these results suggest that the anti-inflammatory effects of catalpalactone are associated with the suppression of NO production and iNOS expression through the inhibition of IRF3, NF-κB, and IFN-β/STAT-1 activation.

Semi-Mechanism-Based Pharmacodynamic Model for the Anti-Inflammatory Effect of Baicalein in LPS-Stimulated RAW264.7 Macrophages

Monitoring of the inhibition of TNF-α, IL-6, iNOS, and NO is used to effectively evaluate anti-inflammatory drugs. Baicalein was found to have good anti-inflammatory activities, but its detailed cellular pharmacodynamic events have not been expatiated by any other study. The inflammatory mediators, including TNF-α, IL-6, iNOS, and NO production in RAW264.7 macrophage induced by LPS, were measured. It was found that these data showed a sequential pattern on time and based on these points a cellular pharmacodynamic model was developed and tested. TNF-α and IL-6 were quantified by ELISA, NO was detected by Griess and iNOS expression was measured by Western blot. The pharmacodynamic model was developed using a NLME modeling program Monolix® 2016R1.¹The results showed that baicalein quickly suppressed release of TNF-α in a concentration-dependent manner, and consequently causing the diminution of IL-6 and iNOS/NO. The pharmacodynamic model simulation successfully described the experimental data, supporting the hypothesis that IL-6 and iNOS /NO release after LPS stimulation is mediated by TNF-α rather than LPS directly. The pharmacodynamic model allowed a well understanding of the cellular pharmacodynamic mechanism of baicalein in the treatment of inflammatory diseases.

Simultaneous purification of dihydrotanshinone, tanshinone I, cryptotanshinone, and tanshinone IIA from Salvia miltiorrhiza and their anti-inflammatory activities investigation

Dihydrotanshinone, tanshinone I, cryptotanshinone, and tanshinone IIA are major lipid-soluble constituents isolated from Salvia miltiorrhiza Bunge (Danshen). In the present study, a systematic method was developed to simultaneously isolate and purify those compounds using macroporous adsorption resins and semi-preparative HPLC with a dynamic axial compress (DAC) system. The Danshen extract (95% alcohol) was divided into three fractions using different concentrations of alcohol (0%, 45%, and 90%) on D101 column. The content of total tanshinones of 90% alcohol eluent (TTS) was over 97%. Furthermore, the anti-inflammatory effects of those samples were investigated on LPS-stimulated RAW264.7 cells and three animal models. The results showed that the anti-inflammatory effect of TTS in vitro was superior to the one of any other sample including 0% and 45% eluent, and total tanshinones capsules. In addition, TTS exhibited a stronger anti-inflammatory effect than that of dihydrotanshinone, tanshinone IIA, cryptotanshinone, and tanshinone I, respectively. For animal models, TTS could significantly suppress xylene-induced ear oedema and rescue LPS-induced septic death and acute kidney injury in mice. In summary, the separation process developed in the study was high-efficiency, economic, and low-contamination, which was fit to industrial producing. TTS is a potential agent for the treatment of inflammatory diseases.

Simultaneous purification of dihydrotanshinone, tanshinone I, cryptotanshinone, and tanshinone IIA from Salvia miltiorrhiza and their anti-inflammatory activities investigation

Dihydrotanshinone, tanshinone I, cryptotanshinone, and tanshinone IIA are major lipid-soluble constituents isolated from Salvia miltiorrhiza Bunge (Danshen). In the present study, a systematic method was developed to simultaneously isolate and purify those compounds using macroporous adsorption resins and semi-preparative HPLC with a dynamic axial compress (DAC) system. The Danshen extract (95% alcohol) was divided into three fractions using different concentrations of alcohol (0%, 45%, and 90%) on D101 column. The content of total tanshinones of 90% alcohol eluent (TTS) was over 97%. Furthermore, the anti-inflammatory effects of those samples were investigated on LPS-stimulated RAW264.7 cells and three animal models. The results showed that the anti-inflammatory effect of TTS in vitro was superior to the one of any other sample including 0% and 45% eluent, and total tanshinones capsules. In addition, TTS exhibited a stronger anti-inflammatory effect than that of dihydrotanshinone, tanshinone IIA, cryptotanshinone, and tanshinone I, respectively. For animal models, TTS could significantly suppress xylene-induced ear oedema and rescue LPS-induced septic death and acute kidney injury in mice. In summary, the separation process developed in the study was high-efficiency, economic, and low-contamination, which was fit to industrial producing. TTS is a potential agent for the treatment of inflammatory diseases.

Arsenic affects inflammatory cytokine expression in Gallus gallus brain tissues

Background

The heavy metal arsenic is widely distributed in nature and posses a serious threat to organism’s health. However, little is known about the arsenic-induced inflammatory response in the brain tissues of birds and the relationship and mechanism of the inflammatory response. The purpose of this study was to explore the effects of dietary arsenic on the expression of inflammatory cytokines in the brains of Gallus gallus.

Results

Seventy-two 1-day-old male Hy-line chickens were divided into a control group, a low arsenic trioxide (As₂O₃)-treated (7.5 mg/kg) group, a middle As₂O₃-treated (15 mg/kg) group, and a high As₂O₃-treated (30 mg/kg) group. Arsenic exposure caused obvious ultrastructural changes. The mRNA levels of the transcription factor nuclear factor-κB (NF-κB) and of pro-inflammatory cytokines, including inducible NO synthase (iNOS), cyclooxygenase-2 (COX-2), and prostaglandin E synthase (PTGEs), in chicken brain tissues (cerebrum, cerebellum, thalamus, brainstem and myelencephalon) on days 30, 60 and 90, respectively, were measured by real-time PCR. The protein expression of iNOS was detected by western blot. The results showed that after being treated with As₂O_3, the levels of inflammatory-related factor NF-κB and pro-inflammatory cytokines in chicken brain tissues increased (P < 0.05).

Conclusions

Arsenic exposure in the chickens triggered host defence and induced an inflammatory response by regulating the expression of inflammatory-related genes in the cerebrum, cerebellum, thalamus, brainstem and myelencephalon. These data form a foundation for further research on arsenic-induced neurotoxicity in Gallus gallus.

Electronic supplementary material

The online version of this article (doi:10.1186/s12917-017-1066-8) contains supplementary material, which is available to authorized users.

Inhibition of NLRP3 Inflammasome Prevents LPS-Induced Inflammatory Hyperalgesia in Mice: Contribution of NF-κB, Caspase-1/11, ASC, NOX, and NOS Isoforms

The nucleotide-binding domain and leucine-rich repeat protein 3 (NLRP3), an intracellular signaling molecule that senses many environmental- and pathogen/host-derived factors, has been implicated in the pathogenesis of several diseases associated with inflammation. It has been suggested that NLRP3 inflammasome inhibitors may have a therapeutic potential in the treatment of NLRP3-related inflammatory diseases. The aim of this study was to determine whether inhibition of NLRP3 inflammasome prevents inflammatory hyperalgesia induced by lipopolysaccharide (LPS) in mice as well as changes in expression/activity of nuclear factor κB (NF-κB), caspase-1/11, nicotinamide adenine dinucleotide phosphate oxidase (NOX), and endothelial/neuronal/inducible nitric oxide synthase (eNOS/nNOS/iNOS) that may regulate NLRP3/apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC)/pro-caspase-1 inflammasome formation and activity by using a selective NLRP3 inflammasome inhibitor, MCC950. Male mice received saline (10 ml/kg; i.p.), LPS (10 mg/kg; i.p.), and/or MCC950 (3 mg/kg; i.p.). Reaction time to thermal stimuli within 1 min was evaluated after 6 h. The mice were killed and the brains, hearts, and lungs were collected for measurement of NF-κB, caspase-1, caspase-11, NLRP3, ASC, NOX subunits (gp91^phox; NOX2), and p47^phox; NOXO2), nitrotyrosine, eNOS, nNOS, iNOS, and β-actin protein expression, NOS activity, and interleukin (IL)-1β levels. LPS-induced hyperalgesia was associated with a decrease in eNOS, nNOS, and iNOS protein expression and activity as well as an increase in expression of NF-κB p65, caspase-1 p20, caspase-11 p20, NLRP3, ASC, gp91^phox, p47^phox, and nitrotyrosine proteins in addition to elevated IL-1β levels. The LPS-induced changes were prevented by MCC950. The results suggest that inhibition of NLRP3/ASC/pro-caspase-1 inflammasome formation and activity prevents inflammatory hyperalgesia induced by LPS in mice as well as changes in NF-κB, caspase-11, NOX2, NOXO2, and eNOS/nNOS/iNOS expression/activity.

Human SR-BI and SR-BII Potentiate Lipopolysaccharide-Induced Inflammation and Acute Liver and Kidney Injury in Mice

The class B scavenger receptors BI (SR-BI) and BII (SR-BII) are high-density lipoprotein receptors that recognize various pathogens, including bacteria and their products. It has been reported that SR-BI/II null mice are more sensitive than normal mice to endotoxin-induced inflammation and sepsis. Because the SR-BI/II knockout model demonstrates multiple immune and metabolic disorders, we investigated the role of each receptor in the LPS-induced inflammatory response and tissue damage using transgenic mice with pLiv-11-directed expression of human SR-BI (hSR-BI) or human SR-BII (hSR-BII). At 6 h after i.p. LPS injection, transgenic hSR-BI and hSR-BII mice demonstrated markedly higher serum levels of proinflammatory cytokines and 2- to 3-fold increased expression levels of inflammatory mediators in the liver and kidney, compared with wild-type (WT) mice. LPS-stimulated inducible NO synthase expression was 3- to 6-fold higher in the liver and kidney of both transgenic strains, although serum NO levels were similar in all mice. Despite the lower high-density lipoprotein plasma levels, both transgenic strains responded to LPS by a 5-fold increase of plasma corticosterone levels, which were only moderately lower than in WT animals. LPS treatment resulted in MAPK activation in tissues of all mice; however, the strongest response was detected for hepatic extracellular signal-regulated protein kinase 1 and 2 and kidney JNK of both transgenic mice. Histological examination of hepatic and renal tissue from LPS-challenged mice revealed more injury in hSR-BII, but not hSR-BI, transgenic mice versus WT controls. Our findings demonstrate that hSR-BII, and to a lesser extent hSR-BI, significantly increase LPS-induced inflammation and contribute to LPS-induced tissue injury in the liver and kidney, two major organs susceptible to LPS toxicity.

Survival advantage depends on cecal volume rather than cecal length in a mouse model of cecal ligation and puncture

BACKGROUND

Cecal ligation and puncture (CLP) is the most commonly used model to simulate human polymicrobial sepsis. However, the severity of CLP is difficult to be standardized across different laboratories. The aim of the present study was to evaluate the influence of ligated cecal volume and length on mortality in mouse CLP model.

METHODS

Cecal length and volume were measured from 120 Kunming mice subjected to CLP or sham operation. According to cecal volume, mice were divided into three groups, volume0.0∼0.2 (0.0 cm(3)-0.2 cm(3)), volume0.2∼0.4 (0.2 cm(3)-0.4 cm(3)), and volume>0.4 (larger than 0.4 cm(3)). The contents of cytokines, including interleukin-1β, interleukin-6, and TNF-α, were measured at 3 h after surgery. The blood bacterial load and oxidative stress indicators (including malondialdehyde and superoxide dismutase) were measured at 12 h after surgery.

RESULTS

There was no significant difference on 72-h survival rate between the mice with cecum longer than 2 cm and shorter than 2 cm. Compared to the other volume groups, volume>0.4 group showed significantly increased blood bacterial load, malondialdehyde levels in lung and liver, and pro-inflammatory cytokines in serum. Surprisingly, the survival rate in volume>0.4 (0%) group showed significant difference from those of volume0.0∼0.2 group (40%) and volume0.2∼0.4 group (40%).

CONCLUSIONS

The mice in volume>0.4 group have much serious inflammatory reaction and are easier to die. As the proportion of volume>0.4 mice is near 20%, it can have large influence on most of the related studies using this CLP model.

Avermectin induced inflammation damage in king pigeon brain

To determine the effect of Avermectin (AVM) on inflammation damage in king pigeon brain, eighty two-month-old American king pigeons were randomly divided into four groups, and were fed with either commercial diet or AVM-supplemented diet containing 20 mg kg(-1)diet, 40 mg kg(-1)diet, and 60 mg kg(-1)diet AVM for 30, 60 and 90 d, respectively. Then, the expression level of inflammatory factors (iNOS, PTGEs, NF-κB), histological damage, and ultra-structural damage were examined. It showed that AVM caused higher expressions (P<0.05) of iNOS, PTGEs, NF-κB with disorganized histological and ultra-structural structures in cerebrum, cerebellum, and optic lobe. Meanwhile, inflammatory and histopathological damage were induced by AVM in king pigeon brains. In addition, the main targeted organelle in nervous system was mitochondria, which indicated that mitochondria may be relevant to the process of inflammation induced by AVM. To our best knowledge, this is the first report to study the toxic effect of AVM on inflammatory damage in king pigeon. Thus, the information presented in this study is believed to be helpful in supplementing data for further AVM toxicity study.

Endothelial glucocorticoid receptor is required for protection against sepsis

The glucocorticoid receptor (GR) is ubiquitously expressed on nearly all cell types, but tissue-specific deletion of this receptor can produce dramatic whole organism phenotypes. In this study we investigated the role of the endothelial GR in sepsis in vivo and in vitro. Mice with an endothelial-specific GR deletion and controls were treated with 12.5 mg/kg LPS and phenotyped. Mice lacking GR showed significantly increased mortality, more hemodynamic instability, higher nitric oxide levels, and higher levels of the inflammatory cytokines, tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6) compared with controls. There were no differences in rates of apoptosis or macrophage recruitment between the two groups. Both endothelial nitric oxide synthase (eNOS) and inducible nitric oxide synthase (iNOS) expression were increased after LPS challenge in mice with endothelial GR deficiency, and aminoguanidine, a specific iNOS inhibitor in mice was able to rescue hemodynamic collapse in these animals. In vitro, human umbilical vein cells (HUVECs) subjected to GR knockdown by siRNA showed increased expression of eNOS at baseline that persisted after treatment with LPS. Both eNOS and iNOS mRNA was increased by qPCR. In HUVECs lacking GR, NF-κB levels and NF-κB-dependent genes tissue factor and IL-6 were increased compared with controls. Thus, endothelial GR is a critical regulator of NF-κB activation and nitric oxide synthesis in sepsis.

PPARγ delivered by Ch-GNPs onto titanium surfaces inhibits implant-induced inflammation and induces bone mineralization of MC-3T3E1 osteoblast-like cells

OBJECTIVES

To deliver the efficacy and safety of Ch-GNPs (Chitosan gold nanoparticles) conjugated anti-inflammatory molecules peroxisome proliferator activated receptor gamma (PPARγ) on implant surface titanium (Ti) to reduce implant-induced inflammation.

MATERIALS AND METHODS

The Ch-GNPs were conjugated with the PPARγ cDNA through a coacervation process. Conjugation was cast over Ti surfaces by dipping, and cells were seeded on different sizes (6 × 6 × 0.1 cm and 1 × 1 × 0.1 cm; n = 3) of Ti surfaces. The size of Ch-GNPs and surface characterization of Ti was performed using UV-vis spectroscopy, TEM (Transmission electron microscopy) and EDX (energy-dispersive X-ray). The DNA conjugation and transfection capacity of Ch-GNPs were simultaneously confirmed by agarose gel electrophoresis, β-galactosidase staining, and immunoblotting.

RESULTS

The Ch-GNPs were well dispersed and spherical in shape, with average size around 10-20 nm. Ti surfaces coated with Ch-GNPs/LacZ, as transfection efficacy molecule, showed strong β-galactosidase staining in MC-3T3 E1 cells. Cells cultured on Ch-GNPs/PPARγ-coated Ti surfaces were able to inhibit implant-induced inflammation by simultaneously suppressing the expression of tumor necrosis factor- alpha (TNF-α), interleukin-1 beta (IL-1β), inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and matrix metalloproteinase-2 (MMP-2). The inhibition mechanism of Ch-GNPs/PPARγ was due to inhibition of both reactive oxygen species (ROS) and nitric oxide (NO) secretion (n = 3; P < 0.05). In addition, Ch-GNPs/PPARγ was able to increase expression of bone morphogenetic protein (BMP-7) and runt-related transcription factor-2 (RUNX-2). Furthermore, alkaline phosphatase activity (ALP) was also increased than that in control (n = 3; P < 0.01). Whereas, expression of receptor activator of NF-κB ligand (RANKL) was decreased.

CONCLUSIONS

The novel gene delivery materials, like Ch-GNPs, can carry the PPARγ cDNA into the required areas of the implant surfaces, thus aiding to inhibit inflammation and promote osteoblast function. Thus, the PPARγ on implant surfaces may promote its clinical application on peri-implantitis or periodontitis like diseases.

Neuroimaging, biochemical and cellular evidence of protection by mycophenolate mofetil on middle cerebral artery occlusion induced injury in rats

Stroke is a major cause of mortality and disability worldwide. Presently, recombinant tissue plasminogen activator is the only approved drug for the management of acute ischemic stroke. However, it has limitations like narrow therapeutic window and increased risk of intracranial hemorrhage. In previous studies, immunosuppressive agents such as cyclosporine A and tacrolimus have shown neuroprotection by improving neurological functions and infarct volume in models of ischemic stroke. Therefore, the present study was designed to evaluate the effect of mycophenolate mofetil (MMF) on the cerebral ischemic injury in the middle cerebral artery occlusion (MCAo) model in rats. MCAo was carried out in male Wistar rats by inserting an intraluminal thread. One hour after MCAo, the animals were treated with MMF (50, 100, 200mg/kg, i.p.). Reperfusion was done after 2h of occlusion. Thirty minutes after reperfusion, animals were subjected to diffusion-weighted magnetic resonance imaging for assessment of neuroprotective effect of MMF. Twenty four hours after MCAo, motor performance was assessed and the animals were euthanized for estimation of brain malondialdehyde, glutathione, myeloperoxidase and nitric oxide levels. The effect of MMF on apoptosis was also evaluated. MMF significantly attenuated the percent infarct area, apparent diffusion coefficient and signal intensity as compared to a vehicle treated group. Treatment with MMF prevented the motor impairment and significantly reversed the changes in levels of malondialdehyde, glutathione, myeloperoxidase and nitric oxide. MMF treatment significantly reduced the apoptosis. Data of the present study indicate neuroprotective effect of MMF in the experimental model of ischemic stroke.

Anti-inflammatory potential of an ethyl acetate fraction isolated from Justicia gendarussa roots through inhibition of iNOS and COX-2 expression via NF-κB pathway

Justicia gendarussa Burm.f. (J. gendarussa) is a plant used as traditional medicine in different parts of India and China to treat inflammatory disorders like rheumatoid arthritis. But its mechanism of anti-inflammatory action is still unclear. Hence in this context, the objective of our study is to reveal the mechanism of anti-inflammatory activity of J. gendarussa which would form an additional proof to the traditional knowledge of this plant. The anti-inflammatory function and mechanism(s) of action was studied in an ethyl acetate fraction isolated from methanolic extract of J. gendarussa roots (EJG). Anti-inflammatory studies were conducted on rats using partitioned fractions isolated from methanolic extract of J. gendarussa roots. In carrageenan-induced rat paw edema, ethyl acetate fraction brought about 80% and 93% edema inhibition at 3rd and 5th hour at a dose of 50 mg/kg, when compared to other extracts and Voveran. We investigated whether EJG inhibits the release of cycloxygenase (COX), 5-lipoxygenase (5-LOX), interleukin-6 (IL-6) and nuclear factor kappa B (NF-κB) in LPS stimulated human peripheral blood mononuclear cells (hPBMCs). Results shows that EJG dose dependently inhibited LPS-activated COX, 5-LOX, IL-6, and NF-κB in hPBMCs. EJG also reduced LPS induced levels of iNOS and COX-2 mRNA expression in hPBMCs. This study provides an insight into the probable mechanism(s) underlying the anti-inflammatory activity of EJG and therefore, we report the first confirmation of the anti-inflammatory potential of this traditionally employed herbal medicine in vitro.

Cardioprotective effect of resveratrol on lipopolysaccharide-induced oxidative stress in rat

Lipopolysaccharide (LPS) is a glycolipid component of the cell wall of Gram-negative bacteria, which induces a deleterious effect on several organs, including the heart, eventually leading to septic shock and death. Endotoxemia-induced cardiotoxicity is characterized by disturbed intracellular redox balance, excessive reactive oxygen species (ROS) accumulation, inducing DNA, protein, and membrane lipid damage. Resveratrol (trans-3,5,4' trihydroxystilbene; RVT) is a phytoalexin polyphenol that exhibits antioxidant and -inflammatory properties. We investigated the putative effect of a subacute treatment with this natural compound on LPS-induced cardiotoxicity in the rat. We found that resveratrol counteracted LPS-induced lipoperoxidation and decreased superoxide dismutase (SOD) activity, but had no effect on the LPS-induced decrease in catalase (CAT) nor on the increase in peroxidase (POD) activity. Resveratrol also reversed LPS-induced myocardial nitric oxide (NO) elevation. More important, LPS-induced iron depletion from plasma to the myocardial compartment was abolished upon resveratrol treatment. All these data suggest that resveratrol is capable of alleviating LPS-induced cardiotoxicity, and that its mode of action may involve iron-shuttling proteins.

Resveratrol, a red wine polyphenol, attenuates lipopolysaccharide-induced oxidative stress in rat liver

Lipopolysaccharide (LPS) is a glycolipid component of the cell wall of gram-negative bacteria inducing deleterious effects on several organs including the liver and eventually leading to septic shock and death. Endotoxemia-induced hepatotoxicity is characterized by disturbed intracellular redox balance, excessive reactive oxygen species (ROS) accumulation inducing DNA, proteins and membrane lipid damages. Resveratrol (trans-3,5,4' trihydroxystilbene) is a phytoalexin polyphenol exhibiting antioxidant and anti-inflammatory properties. In this study, we investigated the effect of subacute pre-treatment with this natural compound on LPS-induced hepatotoxicity in rat. Resveratrol counteracted LPS-induced lipoperoxidation and depletion of antioxidant enzyme activities as superoxide dismutase (SOD) and catalase (CAT) but slightly glutathione peroxidase (GPx) activity. The polyphenol also abrogated LPS-induced liver and plasma nitric oxide (NO) elevation and attenuated endotoxemia-induced hepatic tissue injury. Importantly resveratrol treatment abolished LPS-induced iron sequestration from plasma to liver compartment. Our data suggest that resveratrol is capable of alleviating LPS-induced hepatotoxicity and that its mode of action may involve differential iron compartmentalization via iron shuttling proteins.

Prevention of lipopolysaccharide-induced mouse lethality by resveratrol

The present study was undertaken to determine whether subacute treatment with resveratrol (RVT) protects mice against lipopolysaccharide (LPS)-induced oxidative stress and mortality as well as the mechanism involved in such protection. Mice were divided into three groups: control, LPS and LPS+RVT. Animals were pre-treated with RVT during 7 days. The survival rate was monitored over 48 h after LPS administration. Survival animals were sacrificed, their kidney, liver and brain homogenized for malondialdehyde (MDA), catalase (CAT) activity, free iron and nitric oxide (NO) determination. Plasma was also processed for transaminases, creatinine, urea, NO and iron measurement. Pre-treatment with resveratrol greatly improved the survival rate of LPS-treated mice. Resveratrol counteracted LPS-induced tissue lipoperoxidation and catalase activity depletion. The polyphenol abrogated LPS-induced liver and kidney dysfunction as increased creatinine and urea as well as transaminases activities. In addition, pre-treatment with resveratrol abrogated LPS-induced tissues and plasma NO elevation and iron sequestration from plasma to tissue compartment. These data suggest that resveratrol prevents LPS-induced lethality and that its mode of action may involve differential iron deposition via iron shuttling proteins.

Selenium restores defective beta-adrenergic receptor response of thoracic aorta in diabetic rats

Increased oxidative stress is one of the basic contributors to the development of the cardiovascular complications in diabetes. Both endothelial and vascular smooth muscle cell dysfunctions are the main sign involved in the pathogenesis of diabetic cardiovascular dysfunction. Matrix metalloproteinases (MMPs) are expressed in the vasculature, and participate in tissue remodeling under pathological conditions such as increased oxidative stress, whereas little is known about effect of hyperglycemia on regulation of MMPs in vascular system. Therefore, we aimed to evaluate the effect of an antioxidant, sodium selenate treatment (0.3 mg/kg for 4 weeks) on function of streptozotocin-diabetic rat aorta. Sodium selenate treatment improved significantly impaired isoproterenol-induced relaxation responses and contraction responses of the aortic strips, and exhibited marked protection against diabetes-induced degenerative changes in the smooth muscle cell morphology. Biochemical data showed that sodium selenate treatment induced a significant regulation of MMP-2 activity and protein loss as well as normalization of increased levels of tissue nitrite and protein thiol oxidation. In addition, this treatment restored diabetes-induced increased levels of endothelin-1, PKC, and cAMP production in the aortic tissue. Taken together, our data demonstrate that these beneficial effects of sodium selenate treatment in diabetics are related to be not only inhibition of increased oxidative stress but also prevention of both receptor- and smooth muscle-mediated dysfunction of vasculature, in part, via regulation of MMP-2. Such an observation provides evidence for potential therapeutic usage of selenium compounds for the amelioration of vascular disorders in diabetes.

Protective effect of resveratrol on acute endotoxemia-induced nephrotoxicity in rat through nitric oxide independent mechanism

Lipopolysaccharide (LPS) is a glycolipid component of the cell wall of gram negative bacteria inducing deleterious effects on the kidney. Endotoxemia-induced nephrotoxicity is characterized by disturbed intracellular redox balance and reactive oxygen species (ROS) accumulation leading to DNA, proteins and membrane lipid damages. Resveratrol (trans-3,5,4'-trihydroxystilbene) is a polyphenol displaying antioxidant and anti-inflammatory properties. This study investigated its effects on LPS-induced nephrotoxicity in rats. Resveratrol counteracted all LPS-induced changes in renal haemodynamic parameters. In the kidney resveratrol abrogated LPS-induced lipoperoxidation and antioxidant enzyme activities depletion as superoxide dismutase (SOD) and catalase (CAT) but not peroxidase (POD) activity. LPS increased plasma and urine nitric oxide (NO) level and resveratrol reversed them. More importantly, LPS-induced iron mobilization from plasma to kidney, which was also abolished by resveratrol treatment. All these results suggest that resveratrol exerted strong antioxidant properties against LPS-induced nephrotoxicity and that its mode of action seemed to involve iron shuttling proteins.

Protective effect of resveratrol in endotoxemia-induced acute phase response in rats

Lipopolysaccharide (LPS), a glycolipid component of the cell wall of gram-negative bacteria can elicit a systemic inflammatory process leading to septic shock and death. Acute phase response is characterized by fever, leucocytosis, thrombocytopenia, altered metabolic responses and redox balance by inducing excessive reactive oxygen species (ROS) generation. Resveratrol (trans-3,5,4' trihydroxystilbene) is a natural polyphenol exhibiting antioxidant and anti-inflammatory properties. We investigated the protective effect of resveratrol on endotoxemia-induced acute phase response in rats. When acutely administered by i.p. route, resveratrol (40 mg/kg b.w.) counteracted the effect of a single injection of LPS (4 mg/kg b.w.) which induced fever, a decrease in white blood cells (WBC) and platelets (PLT) counts. When i.p. administered during 7 days at 20 mg/kg per day (subacute treatment), resveratrol abrogated LPS-induced erythrocytes lipoperoxidation and catalase (CAT) activity depression to control levels. In the plasma compartment, LPS increased malondialdehyde (MDA) via nitric monoxide (NO) elevation and decreased iron level. All these deleterious LPS effects were reversed by a subacute resveratrol pre-treatment via a NO independent way. Resveratrol exhibited potent protective effect on LPS-induced acute phase response in rats.

Deficiency of mitogen-activated protein kinase phosphatase-1 results in iNOS-mediated hypotension in response to low-dose endotoxin

Mitogen-activated protein kinase phosphatase-1 (MKP-1) is essential in limiting the proinflammatory response to lipopolysaccharide (LPS). We hypothesized that Mkp-1(-/-) mice would respond to low-dose LPS with a fall in blood pressure due to augmented expression of inducible nitric oxide (NO) synthase (iNOS). To test this hypothesis, Mkp-1(-/-) mice and their wild-type littermates were treated with 10 microg/kg iv LPS, and mean arterial blood pressure (MAP) and exhaled NO production (exNO) were measured. Tissues were harvested for an assessment of iNOS protein levels. Wild-type mice had no change in MAP or exNO during the experimental period, whereas Mkp-1(-/-) mice had a fall (P < 0.005) in MAP [79 +/- 5% of baseline (BL)] and an increase (P < 0.01) in exNO (266 +/- 50% of BL) after 150 min. The tissue levels of iNOS were greater in Mkp-1(-/-) than in wild-type mice. In additional experiments, 60 min after LPS treatment, Mkp-1(-/-) and wild-type mice were given N(omega)-nitro-l-arginine methyl ester (l-NAME) or aminoguanidine, and MAP and exNO were monitored for 90 min. Treatment with l-NAME prevented the LPS-induced increase in exNO and decrease in MAP but resulted in decreased exNO and elevated MAP in wild-type mice. Aminoguanidine prevented the increase in exNO and the fall in MAP caused by LPS in Mkp-1(-/-) mice, without significantly affecting MAP or exNO in wild-type mice. These results demonstrate that a deficiency of MKP-1 results in an exaggerated hypotensive response to LPS mediated by augmented iNOS expression. We speculate that defects in the Mkp-1 gene may increase susceptibility for the development of septic shock.

Polygonum cuspidatum, compared with baicalin and berberine, inhibits inducible nitric oxide synthase and cyclooxygenase-2 gene expressions in RAW 264.7 macrophages

Polygonum cuspidatum water extract (PCWE) was shown to be a potent inhibitor of lipopolysaccharide (LPS)-induced expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2). PCWE was compared to baicalin isolated from Scutellaria baicalensis Georgi and berberine of Coptidis rhizoma and Phellodendri cortex, for their effects on LPS-induced nitric oxide (NO) production and iNOS and COX-2 gene expressions in RAW 264.7 macrophages. Both PCWE and the compounds inhibited LPS-induced NO production in a concentration-dependent manner without a cytotoxicity. The decrease in NO production was in parallel with the inhibition of LPS-induced iNOS gene expression by PCWE and the compounds. In contrast, iNOS enzyme activity was not inhibited by PCWE and two agents. In addition, only PCWE inhibited LPS-induced prostaglandin E2 (PGE2) production and COX-2 gene expression without affecting COX-2 enzyme activity, while baicalin or berberine did not. Furthermore, N-nitro-L-arginine (NLA) and N-nitro-L-arginine methyl ester (L-NAME) pretreatment enhanced LPS-induced iNOS protein expression, which was inhibited by these PCWE and two agents, although LPS-induced COX-2 protein expression was not affected by NLA and L-NAME. PCWE inhibited PGE2 production and COX-2 protein expression in NLA/LPS or L-NAME/LPS-co-treated RAW 264.7 cell, however, baicalin or berberine did not. From the results, it was concluded that co-treatment with NOS inhibitors and PCWE effectively blocks acute production of NO and inhibits expression of iNOS and COX-2 genes.

Bovine lactoferrin protects lipopolysaccharide-induced diarrhea modulating nitric oxide and prostaglandin E2 in mice

Lactoferrin (Lf), an iron-binding multifunctional glycoprotein, is abundantly present in colostrum and milk of different species such as humans, bovines, and mice. Our previous observation revealed that bovine colostral Lf is transported into the systemic circulation and cerebrospinal fluid from gut-lumen through receptor-mediated transcytosis in calves. Diarrhea caused by Escherichia coli is one of the important causes of infant morbidity and mortality in developing countries. We investigated the effects of bovine lactoferrin (BLf) on lipopolysaccharide (LPS)-induced diarrheogenic activity, gastrointestinal transit (GIT), and intestinal fluid content in mice. LPS accumulated abundant fluid in the small intestine in a dose-dependent manner, induced diarrhea, but decreased the GIT. Pretreatment with BLf significantly attenuated the effects of LPS on the diarrheogenic activity and intestinal content, but reversed the GIT when compared with NG-nitro-L-arginine-methyl ester (L-NAME, a non-selective NOS inhibitor) or indomethacin (an inhibitor of prostaglandin synthesis). Both plasma NO and PGE2 in enterocytes were found to increase in LPS-treated mice and were reversed by BLf. These findings demonstrate that the action of BLf against LPS was specific and it exerts antidiarrheal activity through modulating the cyclooxygenase [NO and PGE2] pathway in the gut.

Extracellular Signal-Regulated Kinase (ERK1/2) Contributes to Endotoxin-Induced Hyporeactivity via Nitric Oxide and Prostacyclin Production in Rat Aorta

This study was conducted to determine if mitogen-activated protein kinases (MAPKs) such as extracellular signal-regulated kinase (ERK1/2) contribute to endotoxin-induced vascular hyporeactivity via nitric oxide (NO) and/or prostacyclin (PGI(2)) production in the rat isolated thoracic aorta. Incubation of endothelium-intact rings with endotoxin (100 microg/ml) for 4 h decreased the E(max) value and increased the EC(50) value of norepinephrine. The endotoxin-induced increase in the EC(50) value of norepinephrine was decreased by phenylene-1,3-bis[ethane-2-isothiourea] dihydrobromide (1,3-PBIT), a selective inducible NO synthase inhibitor, and U0126, a selective inhibitor of ERK1/2 phosphorylation by MAPK kinase. The endotoxin-induced decrease in the E(max) value of norepinephrine was reversed by 1,3-PBIT and further decreased by U0126. 1,3-PBIT and U0126 decreased the endotoxin-induced increase in the tissue nitrite and 6-keto-PGF(1)(alpha) levels. These data suggest that events related to the activation of ERK1/2 contribute to the endotoxin-induced hyporeactivity by increasing NO and PGI(2) production.

Anti-inflammatory potential of Antrodia Camphorata through inhibition of iNOS, COX-2 and cytokines via the NF-kappaB pathway

Antrodia camphorata (A. camphorata), well known in Taiwan as a traditional Chinese medicine, has been shown to exhibit antioxidant and anticancer effects. In the present study, therefore, we have examined the effects of the fermented culture broth of A. camphorata (25-100 microg/ml) in terms of lipopolysaccharide (LPS)-induced nitric oxide (NO) and prostaglandin E2 (PGE2) production, and inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) protein expression in RAW 264.7 macrophages. Our results indicate concentration-dependent A. camphorata inhibition of LPS-induced NO and PGE2 production, without appreciable cytotoxicity on the RAW 264.7 cells. A. camphorata also attenuates the production of LPS-induced tumor necrosis factor (TNF-alpha) and interleukin (IL)-1beta. Furthermore, A. camphorata blocks the IkappaB-alpha degradation induced by LPS. These results indicate that A. camphorata inhibits LPS induction of cytokine, iNOS and COX-2 expression by blocking NF-kappaB activation. Therefore, we report the first confirmation of the anti-inflammatory potential of this traditionally employed herbal medicine in vitro.

Resistance to endotoxic shock in endothelial nitric-oxide synthase (eNOS) knock-out mice: a pro-inflammatory role for eNOS-derived no in vivo

The expression of inducible nitric-oxide synthase (iNOS) and subsequent "high-output" nitric oxide (NO) production underlies the systemic hypotension, inadequate tissue perfusion, and organ failure associated with septic shock. Therefore, modulators of iNOS expression and activity, both endogenous and exogenous, are important in determining the magnitude and time course of this condition. We have shown previously that NO from the constitutive endothelial NOS (eNOS) is necessary to obtain maximal iNOS expression and activity following exposure of murine macrophages to lipopolysaccharide (LPS). Thus, eNOS represents an important regulator of iNOS expression in vitro. Herein, we validate this hypothesis in vivo using a murine model of sepsis. A temporal reduction in iNOS expression and activity was observed in LPS-treated eNOS knock-out (KO) mice as compared with wild-type animals; this was reflected in a more stable hemodynamic profile in eNOS KO mice during endotoxaemia. Furthermore, in human umbilical vein endothelial cells, LPS leads to the activation of eNOS through phosphoinositide 3-kinase- and Akt/protein kinase B-dependent enzyme phosphorylation. These data indicate that the pathogenesis of sepsis is characterized by an initial eNOS activation, with the resultant NO acting as a co-stimulus for the expression of iNOS, and therefore highlight a novel pro-inflammatory role for eNOS.

Arginine vasopressin compromises gut mucosal microcirculation in septic rats

OBJECTIVE

Arginine vasopressin (AVP) is increasingly used in the therapy of septic patients with hypotension. However, its effects on the microvascular networks have not been studied in detail. This study was designed to determine the effects of AVP infusion on the villus microcirculation of the septic rat ileum.

DESIGN

Prospective, placebo-controlled, randomized, single-blinded trial.

SETTING

University research laboratory.

SUBJECTS

Fifteen male Sprague-Dawley rats.

INTERVENTIONS

Twenty-four hours after cecal ligation and perforation to create sepsis (M1), rats (n = 8) received a continuous AVP infusion to increase mean arterial pressure by 20 mm Hg (M2) and 40 mm Hg (M3) from M1. In the control group (n = 7), an equivalent volume of normal saline was infused.

MEASUREMENTS AND MAIN RESULTS

Videomicroscopy was performed on 6-10 villi of ileum mucosa at M1 and was repeated at M2 and M3. Blood was drawn to determine plasma levels of AVP and interleukin-6. At M1, both study groups were hypotensive compared with preseptic data (mean arterial pressure, -25%). The increase in mean arterial pressure was linked to supraphysiologic AVP plasma levels and was accompanied by a decrease in mean mucosal blood flow by 76% at M2 and 81% at M3 (p <.001 vs. control). Red blood cell velocity fell by 45% and 47%, respectively (p <.05 vs. control). Whereas periods of arrested villus blood flow increased from 8.1 +/- 2.6 secs/min to 43.8 +/- 5.2 and 47 +/- 6.2 secs/min at M2 and M3 (p <.001), the diameter of terminal arterioles remained unchanged. In addition, AVP infusion further augmented the sepsis-associated increase in interleukin-6 levels (AVP, 905 +/- 160 vs. control, 638 +/- 55 pg/mL; p =.022).

CONCLUSIONS

This study provides evidence for severe abnormalities in gut mucosal blood flow after AVP infusion in septic rats, accompanied by an augmented inflammatory response to the septic injury. The effects of AVP on microvascular blood flow in this model may be related to AVP activities on larger arterioles (>40 microm), a concomitant reduction in cardiac output, or even both.

NO plays a role in LPS-induced decreases in circulating IGF-I and IGFBP-3 and their gene expression in the liver

In this study, we administered aminoguanidine, a relatively selective inducible nitric oxide synthase (iNOS) inhibitor, to study the role of nitric oxide (NO) in LPS-induced decrease in IGF-I and IGFBP-3. Adult male Wistar rats were injected intraperitoneally with LPS (100 microg/kg), aminoguanidine (100 mg/kg), LPS plus aminoguanidine, or saline. Rats were injected at 1730 and 0830 the next day and killed 4 h after the last injection. LPS administration induced an increase in serum concentrations of nitrite/nitrate (P < 0.01) and a decrease in serum concentrations of growth hormone (GH; P < 0.05) and IGF-I (P < 0.01) as well as in liver IGF-I mRNA levels (P < 0.05). The LPS-induced decrease in serum concentrations of IGF-I and liver IGF-I gene expression seems to be secondary to iNOS activation, since aminoguanidine administration prevented the effect of LPS on circulating IGF-I and its gene expression in the liver. In contrast, LPS-induced decrease in serum GH was not prevented by aminoguanidine administration. LPS injection decreased IGFBP-3 circulating levels (P < 0.05) and its hepatic gene expression (P < 0.01), but endotoxin did not modify the serum IGFBP-3 proteolysis rate. Aminoguanidine administration blocked the inhibitory effect of LPS on both IGFBP-3 serum levels and its hepatic mRNA levels. When aminoguanidine was administered alone, IGFBP-3 serum levels were increased (P < 0.05), whereas its hepatic mRNA levels were decreased. This contrast can be explained by the decrease (P < 0.05) in serum proteolysis of this binding protein caused by aminoguanidine. These data suggest that iNOS plays an important role in LPS-induced decrease in circulating IGF-I and IGFBP-3 by reducing IGF-I and IGFBP-3 gene expression in the liver.

Inhibition of inducible nitric oxide synthase and cyclooxygenase-2 activity by 1,2,3,4,6-Penta-O-galloyl-β-D-glucose in murine macrophage cells

Activated macrophages express inducible isoforms of nitric oxide synthase (iNOS) and cyclooxygenase (COX-2), and produce excessive amounts of nitric oxide (NO) and prostaglandin E2 (PGE2), which play key roles in the processes of inflammation and carcinogenesis. The root of Paeonia lactiflora Pall., and the root cortex of Paeonia suffruticosa Andr., are important Chinese crude drugs used in many traditional prescriptions. 1,2,3,4,6-penta-O-galloyl-beta-D-glucose (PGG) is a major bioactive constituent of both crude drugs. PGG has been shown to possess potent anti-oxidant, anti-mutagenic, anti-proliferative and anti-invasive effects. In this study, we examined the inhibitory effects of 1,2,3,4,6-penta-O-galloyl-beta-D-glucose (PGG) isolated from the root of Paeonia lactiflora Pall. on the COX-2 and iNOS activity in LPS-activated Raw 264.7 cells, COX-1 in HEL cells. To investigate the structure-activity relationships of gallate and gallic acid for the inhibition of iNOS and COX-2 activity, we also examined (-)-epigallocatechin gallate (EGCG), gallic acid, and gallacetophenone. The results of the present study indicated that PGG, EGCG, and gallacetophenone treatment except gallic acid significantly inhibited LPS-induced NO production in LPS-activated macrophages. All of the four compounds significantly inhibited COX-2 activity in LPS-activated macrophages. Among the four compounds examined, PGG revealed the most potent in both iNOS (IC50 approximately 18 microg/mL) and COX-2 inhibitory activity (PGE2: IC50 approximately 8 microg/mL and PGD2: IC50 approximately 12 microg/mL), respectively. Although further studies are needed to elucidate the molecular mechanisms and structure-activity relationship by which PGG exerts its inhibitory actions, our results suggest that PGG might be a candidate for developing anti-inflammatory and cancer chemopreventive agents.

Aminoguanidine, an inducible nitric oxide synthase inhibitor, plus N-acetylcysteine treatment reduce the lipopolysaccharide-augmented hepatotoxicity in rats with cirrhosis

Hepatic cirrhosis is produced in rats by administration of thioacetamide (TAA) (0.3 g/L tap water for a period of three months). This treatment caused an increase in oxidative stress in the liver. Lipopolysaccharide (LPS) administration (5 mg/kg) to rats with cirrhosis was observed to increase hepatotoxicity as well as oxidative stress according to biochemical and histopathological findings. However, aminoguanidine (AG), an inducible nitric oxide synthase (iNOS) inhibitor, plus N-acetylcysteine (NAC) treatment reduced the LPS-augmented hepatotoxicity in rats with cirrhosis without making any changes in oxidative stress in the liver.

Regulation of intestinal nuclear factor-kappaB activity and E-selectin expression during sepsis: a role for peroxynitrite

BACKGROUND & AIMS

During sepsis, the production of both nitric oxide and superoxide are increased. Furthermore, NO and O(2)(-) may interact to produce peroxynitrite. The major aim of the present study was to assess the relative roles of NO, O(2)(-), and ONOO- in the regulation of nuclear factor kappaB (NF-kappaB) activity and subsequent E-selectin expression during the early stages of sepsis.

METHODS

Mice were administered 5 microg lipopolysaccharide (LPS) intraperitoneally, and NF-kappaB activity and E-selectin expression in the small intestine were assessed 3 hours later.

RESULTS

In wild-type mice, increased levels of NF-kappaB in nuclear extracts were noted. By contrast, in both inducible nitric oxide synthase-deficient and transgenic Cu/Zn superoxide dismutase-overexpressing mice, NF-kappaB mobilization to the nucleus was diminished. Pretreatment with a ONOO- decomposition catalyst (5,10,15,20-tetrakis[4-sulfonatophenyl]porphyrinato iron [III] [FeTPPS]) resulted in a diminished impact of LPS on NF-kappaB activation. LPS increased vascular E-selectin expression in wild-type mice. E-selectin expression was diminished in inducible nitric oxide synthase-deficient mice after LPS challenge, but E-selectin expression remained elevated in both Cu/Zn superoxide dismutase transgenic mice and wild-type mice pretreated with FeTPPS.

CONCLUSIONS

Our observations suggest that NO, O(2)(-), and ONOO- production are all important mediators in the induction of NF-kappaB activity during endotoxemia and that, in vivo, E-selectin expression on endothelium may not always be associated with whole-organ NF-kappaB activation.

Differential effects of prophylactic, concurrent and therapeutic lactoferrin treatment on LPS-induced inflammatory responses in mice

Mice injected with endotoxin develop endotoxaemia and endotoxin-induced death, accompanied by the oxidative burst and overproduction of inflammatory mediators. Lactoferrin, an iron binding protein, provides a natural feedback mechanism to control the development of such metabolic imbalance and protects against deleterious effects of endotoxin. We investigated the effects of intraperitoneal administration of human lactoferrin on lipopolysaccharide (LPS)-induced release of tumour necrosis factor alpha (TNF-alpha), interleukin 6 (IL-6), interleukin 10 (IL-10) and nitric oxide (NO) in vivo. Lactoferrin was administered as a prophylactic, concurrent or therapeutic event relative to endotoxic shock by intravenous injection of LPS. Inflammatory mediators were measured in serum at 2, 6 and 18 h post-shock induction. Administration of lactoferrin 1 h before LPS resulted in a rather uniform inhibition of all mediators; TNF by 82%, IL-6 by 43%, IL-10 by 47% at 2 h following LPS injection,and reduction in NO (80%) at 6 h post-shock. Prophylactic administration of lactoferrin at 18 h prior to LPS injection resulted in similar decreases in TNF-alpha (95%) and in NO (62%), but no statistical reduction in IL-6 or IL-10. Similarly, when lactoferrin was administered as a therapeutic post-induction of endotoxic shock, significant reductions were apparent in TNF-alpha and NO in serum, but no significant effect was seen on IL-6 and IL-10. These results suggest that the mechanism of action for lactoferrin contains a component for differential regulation of cellular immune responses during in vivo models of sepsis.

Regulation of cardiac remodeling by nitric oxide: focus on cardiac myocyte hypertrophy and apoptosis

Cardiac hypertrophy occurs in pathological conditions associated with chronic increases in hemodynamic load. Although hypertrophy can initially be viewed as a salutary response, ultimately, it often enters a phase of pathological remodeling that may lead to heart failure and premature death. A prevailing concept predicts that changes in gene expression in hypertrophied cardiac myocytes and cardiac myocyte loss by apoptosis contribute to the transition from hypertrophy to failure. In recent years, nitric oxide (NO) has emerged as an important regulator of cardiac remodeling. Specifically, NO has been recognized as a potent antihypertrophic and proapoptotic mediator in cultured cardiac myocytes. Studies in genetically engineered mice have extended these findings to the in vivo situation. It appears that low levels and transient release of NO by endothelial NO synthase exert beneficial effects on the remodeling process by reducing cardiac myocyte hypertrophy, cavity dilation and mortality. By contrast, high levels and sustained production of NO by inducible NO synthase seem to be maladaptive by reducing ventricular contractile function, and increasing cardiac myocyte apoptosis, and mortality. In the future, these novel insights into the role of NO in cardiac remodeling should allow the development of novel therapeutic strategies to treat cardiac remodeling and failure.

PPA250 [3-(2,4-difluorophenyl)-6-[2-[4-(1H-imidazol-1-ylmethyl) phenoxy]ethoxy]-2-phenylpyridine], a novel orally effective inhibitor of the dimerization of inducible nitric-oxide synthase, exhibits an anti-inflammatory effect in animal models of chronic arthritis

Nitric oxide (NO) plays an important role in various physiological processes. Excessive NO production is closely related to inflammatory and autoimmune diseases such as septic shock and rheumatoid arthritis. Suppression of excess NO formation in participating cells may be helpful in improving disease status. In this study, we examined the effects of a newly synthesized imidazole derivative, 3-(2,4-difluorophenyl)-6-[2-[4-(1H-imidazol-1-ylmethyl) phenoxy]ethoxy]-2-phenylpyridine (PPA250), on NO production in vitro and in vivo, as well as on the dimerization of inducible nitric-oxide synthase (iNOS). PPA250 at concentrations of 25 nM and higher inhibited NO production in activated mouse macrophage-like RAW264.7 cells. The IC(50) was approximately 82 nM. Western blot analysis revealed that PPA250 prevents dimerization of iNOS but has no effect on transcription and translation. In addition, oral administration of PPA250 (10 mg/kg and higher) reduced the NO concentration in serum from mice in which sepsis was induced by bacterial lipopolysaccharide. Since the inhibitory activity was observed not only in vitro but also in vivo, we examined the therapeutic potential of PPA250 in two animal models of arthritis, collagen-induced arthritis in mice and adjuvant arthritis in rats. PPA250 suppressed the development of a destructive polyarthritis in both models after the appearance of clinical signs. These results indicate that inhibitors of iNOS homodimerization, including PPA250, could be useful therapeutic agents for inflammatory and autoimmune diseases, such as rheumatoid arthritis, in which NO is involved.

Hepatoprotective role of ganoderma lucidum polysaccharide against BCG-induced immune liver injury in mice

AIM: To examine the effect of ganoderma lucidum polysaccharide (GLP) on the immune liver injury induced by BCG infection, and investigate the relationship between degrees of hepatic damage and NO production in mice.

METHODS: Immune hepatic injury was markedly induced by BCG-pretreatment (125 mg·kg^-1, 2-week, iv) or by BCG-pretreatment plus lipopolysaccharide (LPS, 125 μg·kg^-1, 12-hour, iv) in mice in vivo. Hepatocellular damage induced by BCG-pretreated plus inflammatory cytokines mixture (CM), which was included TNF-α, IL-1β, IFN-γ and LPS in culture medium in vitro. Administration of GLP was performed by oral or incubating with culture medium at immune stimuli simultaneity. Liver damage was determined by activity of alanine aminotransferase (ALT) in serum and in hepatocytes cultured supernatant, by liver weight changes and histopathological examination. NO production in the cultured supernatant was determined by the Griess reaction. Moreover, inducible nitric oxide synthase (iNOS) protein expression was also examinated by immunohistochemical method.

RESULTS: Immune hepatic injury was markedly induced by BCG or BCG plus inflammatory cytokines in BALB/c mice in vivo and in vitro. Under BCG-stimulated condition, augment of the liver weight and increase of the serum/supernatant ALT level were observed, as well as granuloma forming and inflammatory cells soakage were observed by microscopic analysis within liver tissues. Moreover, NO production was also increased by BCG or/and CM stimuli in the culture supernatant, and a lot of iNOS positive staining was observed in BCG-prestimulated hepatic sections. Application of GLP significantly mitigated hepatic tumefaction, decreased ALT enzyme release and NO production in serum/supernatant, improved the pathological changes of chronic and acute inflammation induced by BCG-stimuli in mice. Moreover, the immunohistochemical result showed that GLP inhibited iNOS protein expression in BCG-immune hepatic damage model.

CONCLUSION: The present study indicates that NO participates in immune liver injury induced by Mycobacterium bovis BCG infection. The mechanisms of protective roles by GLP for BCG-induced immune liver injury may be due to influence NO production in mice.

Circadian variation of nitric oxide synthase activity in mouse tissue

Endogenous nitric oxide (NO) is an important mediator in the processes that control biological clocks and circadian rhythms. The present study was designed to elucidate if NO synthase (NOS) activity in the brain, kidney, testis, aorta, and lungs and plasma NOx levels in mice are controlled by an endogenous circadian pacemaker. Male BALB/c mice were exposed to two different lighting regimens of either light-dark 14:10 (LD) or continuous lighting (LL). At nine different equidistant time points (commencing at 09:00h) blood samples and tissues were taken from mice. The plasma and tissue homogenates were used to measure the levels of NO2 + NO3- (NOx) and total protein. The NOx concentrations were determined by a commercial nitric oxide synthase assay kit, and protein content was assessed in each homogenate tissue sample by the Lowry method. Nitric oxide synthase activity was calculated as pmol/mg protein/h. The resulting patterns were analyzed by the single cosinor method for pre-adjusted periods and by curve-fitting programs to elucidate compound rhythmicity. The NOS activity in kidneys of mice exposed to LD exhibited a circadian rhythm, but no rhythmicity was detected in mice exposed to LL. Aortic NOS activity displayed 24h rhythmicity only in LL. Brain, testis, and lung NOS activity and plasma NOx levels displayed 24h rhythms both in LD and LL. Acrophase values of NOS activity in brain, kidney, testis, and lungs were at midnight corresponding to their behavioral activities. Compound rhythms were also detected in many of the examined patterns. The findings suggest that NOS activity in mouse brain, aorta, lung, and testis are regulated by an endogenous clock, while in kidney the rhythm in NOS activity is synchronized by the exogenous signals.

Inducible nitric oxide synthase plays a role in LPS-induced hyperglycemia and insulin resistance

The molecular mechanisms underlying endotoxin-induced insulin resistance remain unclear. Endotoxin or lipopolysaccharide (LPS) injection is a potent stimulator of inducible nitric oxide synthase (iNOS). This study in rats, using the specific iNOS inhibitor aminoguanidine, investigated the role of iNOS in endotoxin-induced hyperglycemia and insulin resistance. LPS injection led to hyperglycemia, insulin resistance, and increased iNOS protein expression and activity. Aminoguanidine prevented LPS-induced hyperglycemia without affecting insulin levels or iNOS expression. Aminoguanidine attenuated the LPS-induced insulin resistance, reflected by the requirement for a higher glucose infusion rate to maintain euglycemia during a hyperinsulinemic clamp study. Aminoguanidine completely blocked the LPS-elevated hepatic glucose output and also inhibited LPS-induced increases in hepatic glycogen phosphorylase activities and phosphoenolpyruvate carboxykinase (PEPCK) mRNA expression, key enzymes for glycogenolysis and gluconeogenesis, respectively. Thus, these data demonstrate an important role for iNOS in LPS-induced insulin resistance, evidenced by the attenuation of LPS-induced hyperglycemia and reversal of increased hepatic glucose output by aminoguanidine. The protective effect of aminoguanidine on insulin resistance is probably by attenuation of hepatic glucose output via its inhibition of key enzymes for glycogenolysis and gluconeogenesis, including glycogen phosphorylase and PEPCK.

Is nitric oxide overproduction the target of choice for the management of septic shock?

Sepsis is a heterogeneous class of syndromes caused by a systemic inflammatory response to infection. Septic shock, a severe form of sepsis, is associated with the development of progressive damage in multiple organs, and is a leading cause of patient mortality in intensive care units. Despite important advances in understanding its pathophysiology, therapy remains largely symptomatic and supportive. A decade ago, the overproduction of nitric oxide (NO) had been discovered as a potentially important event in this condition. As a result, great hopes arose that the pharmacological inhibition of NO synthesis could be developed into an efficient, mechanism-based therapeutic approach. Since then, an extraordinary effort by the scientific community has brought a deeper insight regarding the feasibility of this goal. Here we present in summary form the present state of knowledge of the biological chemistry and physiology of NO. We then proceed to a systematic review of experimental and clinical data, indicating an up-regulation of NO production in septic shock; information on the role of NO in septic shock, as provided by experiments in transgenic mice that lack the ability to up-regulate NO production; effects of pharmacological inhibitors of NO production in various experimental models of septic shock; and relevant clinical experience. The accrued evidence suggests that the contribution of NO to the pathophysiology of septic shock is highly heterogeneous and, therefore, difficult to target therapeutically without appropriate monitoring tools, which do not exist at present.

Endotoxin-induced vascular hyporesponsiveness in rat aorta: in vitro effect of aminoguanidine

The current study was designed to evaluate the endotoxin-induced alterations of the mechanisms involved in Ca(2+)handling within the rat thoracic aorta and further to examine whether in vitro inhibition of inducible nitric oxide synthase (iNOS) by aminoguanidine would account for this effect or not. Endothelium denuded aortic rings from rats injected with lipopolysaccharide (LPS) (5 mg kg(-1), i.p. 18 h prior to functional studies) or saline were mounted in isolated organ baths. Various experimental conditions were studied on paired rings of the same animal which were incubated in the presence or absence of aminoguanidine (100 microM). Phenylephrine contractility in Ca(2+)-containing buffer or in Ca(2+)-free buffer, contractions induced by K(+)depolarization and CaCl(2)in depolarized muscle and by caffeine exposure were significantly decreased in LPS-treated rings and were reversed by aminoguanidine exposure. Aminoguanidine also improved the contractions recorded while switching the Ca(2+)-free buffer to Ca(2+)-containing buffer. We conclude that endotoxin induces a generalized contractile defect in vascular smooth muscle including impairment in the influx of extracellular Ca(2+)and release of Ca(2+)from intracellular stores. An increase in iNOS activation leading to excessive nitric oxide synthesis, possibly non-endothelial in origin, may account for this defect.

Effects of aminoguanidine on nitric oxide production induced by inflammatory cytokines and endotoxin in cultured rat hepatocytes

AIM: To study the effects of aminoguanidine (AG) and two L-arginine analogues N^ω-nitro-L-arginine methyl ester (L-NAME) and N^ω-nitro-L-arginine (L-NNA) on nitric oxide (NO) production induced by cytokines (TNF-α, IL-1β, and IFN-γ) and bacterial lipopolysaccharide (LPS) mixture (CM) in the cultured rat hepatocytes, and examine their mechanisms action.

METHODS: Rat hepatocytes were incubated with AG, L-NAME, L-NNA, Actinomycin D (ActD) and dexamethasone in a medium containing CM (LPS plus TNF-α, IL-1β, and IFN-γ) for 24 h. NO production in the cultured supernatant was measured with the Griess reaction. Intracellular cGMP level was detected with radioimmunoassy.

RESULTS: NO production was markedly blocked by AG and L-NAME in a dose-dependent manner under inflammatory stimuli condition triggered by CM in vitro. The rate of the maximum inhibitory effects of L-NAME (38.9%) was less potent than that obtained with AG (53.7%, P < 0.05). There was no significant difference between the inhibitory effects of AG and two L-arginine analogues on intracellular cGMP accumulation in rat cultured hepatocytes. Non-specific NOS expression inhibitor dexamethasone(DEX) and iNOS mRNA transcriptional inhibitor ActD also significantly inhibited CM-induced NO production. AG (0.1 mmol·L^-1) and ActD (0.2 ng·L^-1) were equipotent in decreasing NO production induced by inflammatory stimuli in vitro, and both effects were more potent than that induced by non-selectivity NOS activity inhibitor L-NAME (0.1 mmol·L^-1) under similar stimuli conditions (P < 0.01).

CONCLUSION: AG is a potent selective inhibitor of inducible isoform of NOS, and the mechanism of action may be not only competitive inhibition in the substrate level, but also the gene expression level in rat hepatocytes.

Wogonin, baicalin, and baicalein inhibition of inducible nitric oxide synthase and cyclooxygenase-2 gene expressions induced by nitric oxide synthase inhibitors and lipopolysaccharide

We previously reported that oroxylin A, a polyphenolic compound, was a potent inhibitor of lipopolysaccharide (LPS)-induced expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2). In the present study, three oroxylin A structurally related polyphenols isolated from the Chinese herb Huang Qui, namely baicalin, baicalein, and wogonin, were examined for their effects on LPS-induced nitric oxide (NO) production and iNOS and COX-2 gene expressions in RAW 264.7 macrophages. The results indicated that these three polyphenolic compounds inhibited LPS-induced NO production in a concentration-dependent manner without a notable cytotoxic effect on these cells. The decrease in NO production was in parallel with the inhibition by these polyphenolic compounds of LPS-induced iNOS gene expression. However, these three compounds did not directly affect iNOS enzyme activity. In addition, wogonin, but not baicalin or baicalein, inhibited LPS-induced prostaglandin E2 (PGE2) production and COX-2 gene expression without affecting COX-2 enzyme activity. Furthermore, N-nitro-L-arginine (NLA) and N-nitro-L-arginine methyl ester (L-NAME) pretreatment enhanced LPS-induced iNOS (but not COX-2) protein expression, which was inhibited by these three polyphenolic compounds. Wogonin, but not baicalin or baicalein, similarly inhibited PGE2 production and COX-2 protein expression in NLA/LPS or L-NAME/LPS-co-treated RAW 264.7 cells. These results indicated that co-treatment with NOS inhibitors and polyphenolic compounds such as wogonin effectively blocks acute production of NO and, at the same time, inhibits expression of iNOS and COX-2 genes.