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1.
The role of Zn(2+) in oxidative stress during endotoxemia was investigated. In rats fed a Zn(2+)-deficient diet (Zn(2+) concentration of less than 1.5 mg/kg) for 8 weeks, the Zn(2+) level in the serum was about 62% lower than that in rats fed a Zn(2+)-adequate diet (Zn(2+) concentration, 50 mg/kg). The Zn(2+) level in serum 18 h after administration of endotoxin (6 mg/kg, i.p.) to Zn(2+)-deficient diet rats was markedly lower than that of the endotoxin/Zn(2+)-adequate diet group. Lipid peroxide formation in the liver of Zn(2+)-deficient diet rats was markedly increased 18 h after endotoxin injection compared with that in the endotoxin/Zn(2+)-adequate diet group. Metallothionein in the liver of endotoxin/Zn(2+)-adequate diet rats was increased more than 17-fold by endotoxin administration, while a markedly lower level of metallothionein was observed in the endotoxin/Zn(2+)-deficient diet group. On the other hand, treatment with ZnSO(4) (100 microM) significantly increased endotoxin (1 microg/ml)-induced tumor necrosis factor-alpha (TNF-alpha) production in J774A.1 cells. Our results clearly demonstrated that treatment with ZnSO(4) significantly inhibited the endotoxin-induced increase in intracellular Ca(2+) level in J774A.1 cells. However, a cell membrane-permeable Zn(2+) chelator, N,N,N',N'-tetrakis (2-pyridylmethyl) ethylenediamine (TPEN, 1 microM), did not affect the endotoxin-induced TNF-alpha production or Ca(2+) level in J774A.1 cells. In addition, we investigated whether Zn(2+) can suppress nitric oxide (NO) generation and cytotoxicity in endotoxin-treated cells. Treatment with ZnSO(4) (50 microM) significantly inhibited endotoxin-induced NO production in J774A.1 cells, but did not affect endotoxin-induced cytotoxicity. These findings suggest that zinc may play an important role, at least in part, in the oxidative stress during endotoxemia.  相似文献   

2.
This study investigated the effect of nitric oxide on lipid peroxide formation during endotoxaemia. Nitric oxide synthase inhibitors N(G)-monomethyl-L-arginine acetate (L-NMMA, 20 mg/kg, intravenously), N(G)-nitro-L-arginine-methyl ester (L-NAME, 10 mg/kg, intravenously), and N(G)-nitro-L-arginine (L-NA, 10 mg/kg, intravenously), and a relatively selective inducible nitric oxide synthase inhibitor aminoguanidine (10 mg/kg, intravenously), did not protect against endotoxin-induced death of mice. Superoxide dismutase activity in liver 18 hr after administration of endotoxin (6 mg/kg, intraperitoneally) to L-arginine analogues (L-NMMA, L-NAME, L-NA)-treated mice was lower than in mice treated with endotoxin alone, whereas the administration of L-arginine analogues increased xanthine oxidase activity in the livers of endotoxin-injected mice compared with mice treated with endotoxin alone. In mice treated with L-arginine analogues and aminoguanidine, the levels of non-protein sulfhydryl and lipid peroxide in liver 18 hr after endotoxin injection did not show significant differences from mice treated with endotoxin alone. L-Arginine analogues and aminoguanidine had little effect on lipid peroxide formation in liver caused by endotoxin. Treatment with aminoguanidine (300 microM) significantly inhibited endotoxin-induced intracellular peroxide in J774A.1 cells, however, aminoguanidine did not affect endotoxin-induced cytotoxicity in J774A.1 cells. Our results clearly demonstrate that treatment with catalase (10 microg/ml), D-mannitol (10 mM), or superoxide dismutase (100 U/ml), has little or no effect on nitric oxide production by endotoxin (1 microg/ml)-activated J774A.1 cells. These findings suggest that nitric oxide is not crucial for lipid peroxide formation during endotoxaemia. Therefore, it is unlikely that nitric oxide plays a significant role in liver injury caused by free radical generation in endotoxaemia.  相似文献   

3.
Sho-saiko-to, one of the the most frequently prescribed Kampo medicines, is used to treat chronic hepatitis and has shown confirmed clinical efficacy. The present study was performed with respect to heme metabolism to study the preventive effects of Sho-saiko-to against endotoxemia. Endotoxin was injected intraperitoneally at a dose of 6 mg/kg into Sho-saiko-to (500 mg/kg/d, p.o.)-pretreated rats, and its administration clearly prevented the endotoxin-induced hypoferremia. In rats pretreated with Sho-saiko-to, the activity of hepatic delta-aminolevulinate synthetase and cytochrome P-450 level 18 h after endotoxin injection were significantly increased as compared to rats treated with endotoxin alone. Similarly, Sho-saiko-to significantly depressed the endotoxin-induced increase in heme oxygenase activity in liver microsomes. These findings suggested that the extent of shock syndrome caused by endotoxin may be due, at least in part, to changes in heme metabolic disturbance during endotoxemia. Sho-saiko-to may therefore protect rats against lethality caused by endotoxin through its ability to regulate the heme metabolism in septic shock.  相似文献   

4.
The preventive effects of cepharanthine, a biscoclaurine alkaloid isolated from Stephania cepharantha Hayata, on the lethality and cell death caused by endotoxin or tumor necrosis factor (TNF)-alpha-induced syndrome in septic shock were investigated. In these experiments, we estimated the survival of mice treated with a lethal dose of endotoxin (50 mg/kg, i.p.) or recombinant human (rh) TNF-alpha (10,000 units/mouse, i.v.) together with a sublethal dose (1 mg/kg, i.p.) of endotoxin. Cepharanthine clearly protected mice from endotoxin-induced and endotoxin/rhTNF-alpha-induced lethal shock. In in vitro experiments, cepharanthine (3 micro g/ml) definitely inhibited cell death in mouse L929 fibroblast cells incubated with rhTNF-alpha (100 units/ml) at 37 degrees C for 24 h. On the other hand, non-apoptotic programmed death of cells was observed by fluorescence microscopy in rhTNF-alpha (100 units/ml)-treated L929 cells. In the 3-(4,5-Dimethylthiazol-2-yl) 2,5-diphenyltetrazolium bromide (MTT) assay after 48-h drug exposure, the cell proliferation of L929 cells was significantly increased by the addition of cepharanthine (1 and 3 micro g/ml). It seems that the preventive effect of cepharanthine on rhTNF-alpha-induced cytotoxicity in fibroblast cells occurs through an increase of cell proliferation by the drug. In addition, cepharanthine suppressed nitric oxide (NO) production by endotoxin-stimulated Raw 264.7 mouse macrophage cells. These findings suggest that cepharanthine prevents lethality or cytotoxicity through suppression of endotoxin-induced NO in macrophages and that its effects are possibly mediated by the enhancement of the proliferation of fibroblast cells. Cepharanthine may therefore protect against some of the various disturbances caused by endotoxin through its ability to inhibit NO production in septic shock.  相似文献   

5.
We examined the role of intracellular Ca2+ in the mechanism of the preventive effects of the Ca2+-channel blocker verapamil against lipoprotein disturbances during tumor necrosis factor (TNFa)-induced shock syndrome. The heparin-releasable lipoprotein lipase (LPL) activity in plasma of TNFalpha (5 X 10(4) units/mouse, i.v.)-injected mice was markedly lower at 4 h post-intoxication than in the controls. In mice treated with verapamil (10 mg/kg, s.c.), the activity of LPL 4 h after TNFalpha injection was significantly higher than in mice treated with TNFalpha alone. On the other hand, on polyacrylamide gel disk electrophoresis, very low density lipoprotein (VLDL) and high density lipoprotein (HDL) fractions in the sera of TNFalpha-injected mice were increased and reduced, respectively, relative to the controls. The administration of verapamil clearly prevented the lipoprotein damage arising from TNFalpha challenge. We investigated whether verapamil could suppress TNFalpha generation in endotoxin-treated J774A.1 cells. Treatment with verapamil (30 microM) markedly inhibited endotoxin (1 microg/ml)-induced TNFalpha production in these cells. These findings suggest that the concentration of intracellular Ca2+ may contribute to the extent of lipoprotein disturbances in plasma, which results from LPL suppression in TNFalpha-induced shock syndrome. Verapamil may, therefore, protect against some of the various disturbances caused by changes in Ca2+ mobilization through its ability to inhibit TNFalpha production in septic shock.  相似文献   

6.
DDT is still widely used in several parts of the world to control malaria, typhoid and dengue vectors, even though its use was banned in many countries based on toxicity data in wild life species. DDT has been shown to have immunotoxic effects in mice and to increase susceptibility to intracellular pathogens such as Mycobacterium leprae. However, little is known about the mechanisms underlying this effect. Activated macrophages play an important defensive role against intracellular pathogens, therefore our objective was to evaluate the effect of in vitro exposure to technical grade DDT (a mixture of three forms: 1,1,1-thricloro-2,2-bis(p-chlorophenyl)ethane (p,p'-DDT) (85%), o,p'-DDT (15%) and o,o'-DDT (trace amounts)), p,p'-DDT, 1,1-dicloro-2,2-bis(p-chlorophenyl)ethylene (p,p'-DDE) and 1,1-dichloro-2,2-bis(p-chlorophenyl)ethane on the functional activation of J774A.1 macrophages and their capability to limit growth of intracellular pathogens, using Mycobacterium microti as a model. We evaluated cytotoxicity and the effect on cell proliferation of 2.5, 5.0 and 10 microg/ml of DDT compounds. Functional macrophage activity (NO(*) and O(2)(-) production, and mRNA expression of TNF-alpha, IL-1beta and iNO synthase) and the ability of treated cells to limit infection by M. microti in IFN-gamma-activated macrophages were evaluated in cells exposed to 2.5 microg/ml of DDT compounds. Doses of 5 and 10 microg/ml induced direct cytotoxic effects precluding meaningful analysis of the above parameters, whereas 2.5 microg/ml of all DDT compounds inhibited macrophage activity and reduced their ability to limit the intracellular growth of M. microti without inducing cytotoxicity. Technical grade DDT and p,p'-DDE were the more potent compounds. Therefore, exposure to DDT compounds could represent an important risk for infection development by those intracellular pathogens against which NO(*) and/or O(2)(-) production represent the main immune protective mechanism.  相似文献   

7.
The aim of our study was to investigate the effect of the 21-aminosteroid U-74389G [21- < 4-(2,6-di-1-pyrrolidinyl-4-pyrimidinyl)-1-piperazinyl-pregna-1,4,9,(11) triene-3,20-dione(z)-2-butenedionate] on the l-arginine-nitric oxide (NO) pathway in a rat model of endotoxin shock. Endotoxin shock was produced in male rats by a single intravenous (i.v.) injection of 20 mg/kg of Salmonella Enteritidis lipopolysaccharide (LPS). Rats were treated with U-74389G (7.5, 15 and 30 mg/kg i.v.) or vehicle (1 ml/kg i.v.) 5 min after endotoxin challenge. Lipopolysaccharide administration reduced survival rate (0%, 72 h after endotoxin administration) decreased mean arterial blood pressure, enhanced plasma concentration of bilirubin and alanine aminotransferase and increased plasma nitrite concentrations. Lipopolysaccharide injection also increased the activity of inducible NO synthase in the liver and in the aorta. Furthermore aortic rings from shocked rats showed a marked hyporeactivity to phenylephrine (1 nM-10 microM). In addition lipopolysaccharide (50 microg/ml for 4 h) in vitro stimulation significantly increased nitrite production in peritoneal macrophages harvested from normal rats. Treatment with U-74389G (15 and 30 mg/kg i.v., 5 min after endotoxin challenge) significantly protected against lipopolysaccharide-induced lethality (90% survival rate 24 h and 80% 72 h after lipopolysaccharide injection, respectively, following the highest dose of the drug), reduced hypotension, ameliorated liver function, decreased plasma nitrite levels, restored the hyporeactivity of aortic rings to their control values and inhibited the activity of inducible NO synthase in the liver and in the aorta. Finally, U-74389G in vitro (12.5, 25 and 50 microM) significantly inhibited nitrite production in endotoxin stimulated peritoneal macrophages. The data suggest that U-74389G may exert beneficial effects in an experimental model of septic shock by inhibiting the activity of the inducible NO synthase.  相似文献   

8.
The purified dioscorin from yam (Dioscorea alata L. cv. Tainong 1) tuber was previously reported (Hsu et al., 2002. J. Agric. Food Chem., 50, 6109-6113). In this report, we evaluated its immunomodulatory ability in vitro in the presence of polymyxin B (50 microg/ml) to eliminate lipopolysaccharide (LPS) contamination. Dioscorin (5-100 microg/ml) was able to stimulate nitric oxide production (expressed as nitrite concentrations) in RAW264.7 cells. The stimulation index on the phagocytosis of RAW264.7 cells against E. coli and the oxidative burst (determined by the intensity of rhodamine fluorescence) of RAW264.7 cells were both enhanced by different concentrations of dioscorin (5-100 microg/ml). The cytokine production, including IL-6, TNF-alpha, and IL-1beta in dioscorin-treated RAW264.7 cells or human monocytes, was measured in the cultured medium. Dioscorin (5-100 microg/ml) was found able to induce IL-6, TNF-alpha, and IL-1beta production in RAW264.7 cells and human monocytes. To evaluate the effects of dioscorin on the proliferation of spleen cells from BALB/c mice, phytohemagglutinin (PHA, 2 microg/ml) alone or PHA mixed with different concentrations of dioscorin (10, 25, and 50 microg/ml) was used to treat spleen cells for 24h. The stimulated proliferation index of splenic cells ranged from 1.38- to 1.48-fold of PHA alone for PHA mixed with different concentrations of dioscorin (10, 25, and 50 microg/ml). We suggest that the tuber storage protein of yam dioscorin functions as an immunomodulatory substance.  相似文献   

9.
Despite the remarkable progress in intensive care medicine, sepsis and shock continue to be major clinical problems in intensive care units. Septic shock may be associated with a toxic state initiated by the stimulation of monocytes by bacterial toxins such as endotoxin, which is released into the bloodstream. This study describes the role of oxidative stress in endotoxin-induced metabolic disorders. We demonstrate that endotoxin injection results in lipid peroxide formation and membrane injury in experimental animals, causing decreased levels of free radical scavengers or quenchers. Interestingly, it was also suggested that tumor necrosis factor (TNF)-induced oxidative stress occurs as a result of bacterial or endotoxin translocation under conditions of reduced reticuloendothelial system function in various disease states. In addition, we suggest that intracellular Ca2+, Zn2+, or selenium levels may participate, at least in part, in the oxidative stress during endotoxemia. On the other hand, it is also suggested that the extent of endotoxin-induced nitric oxide (NO) formation may be due, at least in part, to a change in heme metabolic regulation during endotoxemia. However, in our experimental model, NO is not crucial for lipid peroxide formation during endotoxemia. Sho-saiko-to is one of the most frequently prescribed Kampo medicines and has primarily been used to treat chronic hepatitis. We report that Sho-saiko-to decreases the rh TNF-induced lethality in galactosamine-hypersensitized mice and protects mice against oxygen toxicity and Ca2+ overload in the cytoplasm or mitochondria during endotoxemia. We further suggest that Sho-saiko-to shows a suppressive effect on NO generation in macrophages stimulated with endotoxin and that it may be useful in improving endotoxin shock symptoms.  相似文献   

10.
Photoluminescent silicon nanoparticles have a bright and stable fluorescence and are promising candidates for bio-imaging, cell staining and drug delivery. With increasing development of nanotechnology applications for biomedicine, an understanding of the potential toxicity of nanoparticles is needed to assess safety concerns for clinical applications. The objective of this study was to compare biological responses of silicon nanoparticles (SNs, 3 nm diameter) with silicon microparticles (SMs, approximately 100-3000 nm diameter) in cultured murine macrophages (RAW 264.7) using standard protocols for assessing cytotoxicity/cell viability and inflammatory responses developed for micron-sized particles. SNs and SMs were exposed to macrophages with and without addition of endotoxin lipopolysaccharide (LPS), a positive inducer of tumor necrosis factor-alpha (TNF-alpha), interleukin 6 (IL-6), and nitric oxide (NO). Cytotoxicity was assayed using the dye exclusion and MTT assays. Cell supernatants were assayed for production TNF-alpha, IL-6 and NO. SNs at concentrations < or = 20 microg ml(-1) exhibited no cytotoxicity or inflammatory responses; however, SNs and SMs >20 and 200 microg ml(-1), respectively, increased cytotoxicity compared with controls. SMs induced concentration-related increases in TNF-alpha and IL-6 production; in contrast, the production of these cytokines was shown to decrease with increasing concentrations of SNs. NO production was not induced by SNs or SMs alone. Fluorescence microscopy demonstrated that SNs were associated with the macrophages, either internalized or attached to cell membranes. In conclusion, evaluating differences in biological responses for nanoparticles compared with microparticles of the same material may help improve tests to assess biological responses of nanoparticles that may be used in biomedical applications.  相似文献   

11.
Pentoxifylline (PTX), a methylxanthine derivative, has been reported to be an effective drug in inhibiting TNF-alpha responses during septic shock. The inhibition of TNF-alpha production seems to be correlated with increased intracellular cAMP levels. PTX also affects the production of other cytokines such as IL-1, IL-6, IL-10, IL-12, and IFN-gamma. However, inhibition, as well as enhancement of cytokine production, has been observed in vitro, depending on the PTX concentration and cell type used.IL-12 is a heterodimeric cytokine that plays an important role in the development of Th1-mediated inflammatory responses. IL-12 along with TNF-alpha and other proinflammatory cytokines has shown to be responsible for the pathological reaction, which may lead to septic shock. For biological activity, the expression of both subunits of IL-12, p35 and p40, is required. Moreover, the p40 chain of IL-12 specifically inhibits the effects of the IL-12 heterodimer.In this study, we investigated the effects of PTX on the production of both proinflammatory (TNF-alpha, IL-6, IL-12) and anti-inflammatory (IL-10) cytokines by murine macrophages (Mφ). We have found that PTX, at concentrations below 100 microg/ml, selectively inhibited the production of TNF-alpha. Forskolin, a cAMP-elevating agent, similarly affected the production of the cytokines tested. However, at higher concentrations, PTX inhibited the production of TNF-alpha, IL-10, and IL-12 p35, but surprisingly, PTX enhanced the production of IL-12 p40. Concentrations of IL-10 were negatively correlated with the concentrations of IL-12 p40 subunit. These results further confirm the relevance of the use of PTX in clinical trials of immunological disorders characterised by inappropriate Th1 type immune responses.  相似文献   

12.
Abstract: The enhancing effect of tumour necrosis factor-α (TNF-α) on oxidative stress with or without a sublethal dose of endotoxin was examined. The mortality of mice treated with recombinant human TNF-α (1X104 units/mouse, intravenously) and endotoxin (0.01-1 mg/kg, intraperitoneally) was dependent on the dose of endotoxin. The liver lipid peroxide level, superoxide anion generation and serum lactate dehydrogenase activity, especially serum lactate dehydrogenase-5 isozyme leakage, in mice 2-4 hr after administration of recombinant human TNF to endotoxin-pretreated mice (0.5 mg/kg, intraperitoneally) were markedly higher than in those without endotoxin, whereas the administration of recombinant human TNF significantly decreased the non-protein sulfhydryl level, superoxide dismutase and glutathione peroxide activities in the liver of endotoxin-injected mice compared with those in mice treated with recombinant human TNF or endotoxin alone. Furthermore, findings clearly demonstrated that J774A.1 cells stimulated with recombinant human TNF (1X104 units/ml) can effectively produce nitric oxide in the presence of endotoxin, and the production was dependent on the dose of endotoxin (0.01-10 μg/ml). The level of lipid peroxide in mice 4 hr after administration of recombinant human TNF and lead acetate (50 mg/kg, intravenously) was markedly higher than that in the mice treated with recombinant human TNF alone. By contrast, injection of polymyxin-B (20 mg/kg, intraperitoneally, an anti-endotoxin drug) markedly decreased the lipid peroxide level in the liver of the mice treated with recombinant human TNF and lead acetate. These findings suggest that the oxidative stress caused by TNF occurs as a enhancing effect of endotoxion or by bacterial translocation from the intestinal gut under reduction of reticuloendothelial system function in various disease states, and that the effect of TNF may cause a marked increase of toxicity of oxidative stress by endotoxin.  相似文献   

13.
Lactoferrin immunomodulation of DTH response in mice   总被引:3,自引:0,他引:3  
Improved nontoxic adjuvants, especially adjuvants capable of inducing cell-mediated immunity (CMI), are needed for research in immunology and for development of human and veterinary vaccines. Bovine Lactoferrin, an effector molecule shown to directly participate in host defense, was assessed at various concentrations as an adjuvant component for induction of DTH responses to sheep red blood cells (SRBC). Subcutaneous immunization with Lactoferrin enhanced delayed type hypersensitivity (DTH) in CBA mice in a dose-dependent fashion; DTH responses were most significantly increased when sensitization was accomplished using Lactoferrin at 50 microg/dose and 250 microg/dose. Furthermore, Lactoferrin admixed with suboptimal dose of SRBC enhanced DTH responses by over 17-fold. Peritoneal cells collected from mice intraperitoneally injected with a 100 microg/dose of Lactoferrin demonstrated modest, but significant, production of TNF-alpha, IL-12 and MIP-1alpha when cultured in vitro, compared to saline-injected controls. J774A.1 murine macrophages stimulated with Lactoferrin resulted in increased TNF-alpha protein production, and upregulated IL-12 and IL-15 mRNA. Levels of message for chemokines MIP-1alpha and MIP-2 were also increased in a dose-dependent way. Taken together, these results indicate that Lactoferrin as an adjuvant may stimulate macrophages to generate a local environment likely to push immune responses towards development and maintenance of CMI.  相似文献   

14.
The herb, Chrysanthemum zawadskii var, latilobum commomly known as Gu-Jul-Cho in Korea, used in traditional medicine to treat pneumonia, bronchitis, cough, common cold, pharyngitis, bladder-related disorders, gastroenteric disorders, and hypertension. Linarin is the main active compound and the biological mechanisms of its activity are unclear. It is believed that effects of this herb may be exerted through the pluripotent effectors of linarin due to its ability to treat a variety of afflictions. In this study, the effects of linarin on the mouse macrophages cell line, RAW 264.7, were investigated. It was found that linarin could activate macrophages by producing cytokines. Monocytes and tissue macrophages produce at least two groups of protein mediators of inflammation, interleukin 1 (IL-1) and the tumor necrosis factor (TNF). Recent studies have shown that TNF and IL-1 modulate the inflammatory function of endothelial cells, leukocytes, and fibroblasts. TNF-alpha production by macrophages treated with linarin occured in a dose dependent manner. However, IL-1 production was largely unaffected by this natural product. This study demonstrated the ability of linarin to activate macrophages both directly and indirectly. Linarin also affect both cytokine production and nitric oxide inhibition, in addition to the expression of some surface molecules. Nitric oxide (NO), derived from L-argin-ine, is produced by two forms(constitutive and inducible) of nitric oxide synthase (NOS). The NO produced in large amounts by inducible NOS is known to be responsible for the vasodilation and hypotension observed in septic shock. Linarin was found to inhibit NO production in the LPS-activated RAW 264.7 cells. Linarin may be a useful candidate as a new drug for treating endotoxemia and the inflammation accompanied by NO overproduction. The linarin-treated total lymphocytes exhibited cytotoxicity in a dose dependent manner between 20 microg/ml and 40 microg/ml. These results suggest that linarin may function through macrophage activation.  相似文献   

15.
Lipopolysaccharide (LPS [endotoxin]), a structural component of gram-negative bacteria, is implicated in the pathogenesis of septic shock. Lipid A is an evolutionarily conserved region of LPS that has been identified as the toxic component of LPS. Therapeutic strategies for the treatment of septic shock in humans are currently focused on neutralization of LPS. Here, the anti-endotoxin activity of BNEP, a synthetic peptide derived from the human bactericidal/permeability-increasing protein (BPI; aa 148-161) was investigated in vitro and in experimental animal endotoxemia models in vivo. The ability of BNEP to bind LPS from Escherichia coli O55:B5 and lipid A from Salmonella Re 595 was tested using an affinity sensor assay, and its ability to neutralize LPS was tested using a sensitive Limulus amebocyte lysate (LAL) assay. Polymyxin B (PMB) was used as the positive control in the in vitro experiments and in mouse experiments. We found that BNEP and PMB bound LPS with a similar affinity (Kd values of 25.4 and 25.8 nM, respectively). In contrast, BNEP bound lipid A with a slightly lower affinity than that of PMB (Kd values of 8 and 5.6 nM, respectively). The exact capacity of BNEP binding to LPS was approximately 0.53 microg peptide per 1 ng of LPS, as shown by affinity sensor assay. The LAL test showed that 256 microg of BNEP almost completely neutralized 2 ng LPS. In vivo, mice were randomized, intravenously injected with BNEP (0.5-10 mg/kg) or 1 mg/kg PMB, and then lethally challenged with 20 mg/kg LPS. We found that 5 mg/kg BNEP significantly protected mice from LPS challenge. In an endotoxemia rat model, animals were co-treated with 5 or 10 mg/kg BNEP and 10 mg/kg LPS via cardiac catheter. BNEP treatment resulted in significant reduction of tumor necrosis factor alpha (TNF-alpha) and IL-6, compared with LPS-only control animals. In addition, 10 mg/kg BNEP-treated animals showed a significant decrease in plasma endotoxin levels in comparison to animals treated with LPS alone. These results provide evidence that BNEP effectively neutralizes LPS in vitro and in vivo, and could protect animals from the lethal effects of LPS via decreasing plasma endotoxin and proinflammatory cytokines. Our work suggests that this peptide is worthy of further investigation as a possible novel treatment for septic shock.  相似文献   

16.
Flavonoids, natural compounds widely distributed in the plant kingdom, are reported to affect the inflammatory process and to possess anti-inflammatory as well as immunomodulatory activity in-vitro and in-vivo. Since nitric oxide (NO) produced by inducible nitric oxide synthase (iNOS) is one of the inflammatory mediators, the effects of the ethanol/water (1:1) extract of the leaves of Apium graveolens var. dulce (celery) on iNOS expression and NO production in the J774.A1 macrophage cell line stimulated for 24 h with Escherichia coli lipopolysaccharide (LPS) were evaluated. The extract of A. graveolens var. dulce contained apiin as the major constituent (1.12%, w/w, of the extract). The extract and apiin showed significant inhibitory activity on nitrite (NO) production in-vitro (IC50 0.073 and 0.08 mg mL(-1) for the extract and apiin, respectively) and iNOS expression (IC50 0.095 and 0.049 mg mL(-1) for the extract and apiin, respectively) in LPS-activated J774.A1 cells. The croton-oil ear test on mice showed that the extract exerted anti-inflammatory activity in-vivo (ID50 730 microg cm(-2)), with a potency seven-times lower than that of indometacin (ID50 93 microg cm(-2)), the non-steroidal anti-inflammatory drug used as reference. Our results clearly indicated the inhibitory activity of the extract and apiin in-vitro on iNOS expression and nitrite production when added before LPS stimulation in the medium of J774.A1 cells. The anti-inflammatory properties of the extract demonstrated in-vivo might have been due to reduction of iNOS enzyme expression.  相似文献   

17.
丁建潮  胡富强  袁弘 《药学学报》2004,39(11):876-880
目的考察单硬脂酸甘油酯固体脂质纳米粒(monostearin solid lipid nanoparticles,MSLN)经PEG2000修饰后,对A549细胞摄取MSLN及J774A1细胞吞噬MSLN的影响。方法采用溶剂扩散法制备MSLN,测定其粒径和zeta电位;以罗丹明B(Rhodamine B)为荧光标记物,研究A549细胞对MSLN的摄取作用和J774A1细胞对MSLN的吞噬作用。结果MSLN的细胞毒性较低,A549细胞对MSLN的摄取可快速接近饱和,其摄取百分率与MSLN在细胞外的浓度呈负相关。结论MSLN经PEG2000修饰,可显著抑制J774A1细胞对MSLN的吞噬,但可增加A549细胞对MSLN的摄取。  相似文献   

18.
1. Laminitis, an important cause of lameness in domestic ungulates, occurs as a result of altered digital perfusion. Endotoxin and cytokines may mediate the vascular derangements observed through alterations in nitric oxide production. In this study, the vascular responses of the isolated ovine digital artery were examined and the influence of endotoxin and cytokines investigated. 2. Neither removal of the endothelium nor incubation with N(G)-nitro-L-arginine methyl ester (L-NAME, 300 microM) altered the response to phenylephrine (PE, 1 nM to 300 microM). Indomethacin (10 microM) decreased PE log EC(50) from -6.22+/-0.08 to -6.55+/-0.07. Acetylcholine (1 nM to 1 mM) and bradykinin (BK, 100 pM to 3 microM) induced endothelium-dependent relaxation. Bradykinin-induced relaxation was reduced by L-NAME, E(max) falling from -61.7+/-7.4 to -34.0+/-2.1%. Addition of indomethacin further reduced BK E(max) to -9.6+/-2.8%. Sodium nitroprusside (1 nM to 300 microM) produced endothelium-independent relaxation that was unaffected by L-NAME or indomethacin. 3. Following a 6 h incubation with endotoxin (3 microml(-1)), arterial responses to PE and BK did not differ from polymyxin B-treated controls (10 microg ml(-1)). Arteries incubated for 6 h with interferon-gamma (IFN-gamma, 10 ng ml(-1)) and tumour necrosis factor-alpha (TNF-alpha, 5 ng ml(-1)) exhibited greater relaxation to BK (E(max)-50.0+/-5.1%) than polymyxin B-treated controls (E(max)-33.1+/-4.0%), but did not differ in their response to PE. 4. Prolonged incubation (16 h) with endotoxin (3 microg ml(-1)) did not alter the response to PE, however incubation with IFN-gamma (10 ng ml(-1)), TNF-alpha (5 ng ml(-1)) and interleukin-1beta (20 ng ml(-1)) for 16 h increased PE log EC(50) from -6.44+/-0.09 to -6. 10+/-0.11. 5. Nitric oxide is an important mediator of endothelium-dependent relaxation in ovine digital arteries but does not modulate PE-induced vasoconstriction. Incubation with cytokines decreased the sensitivity of digital arteries to PE.  相似文献   

19.
This study was performed to investigate whether the toxic effects of Loxosceles gaucho venom on cells might be exerted via stimulators of TNF-alpha release generated by sphingomyelinase D--a major component of the venom. It was demonstrated that L. gaucho venom alone is unable to induce TNF-alpha release by J774A.1 cells, while in the presence of exogenous sphingomyelin it induces a high level of TNF-alpha release which is significantly increased by incubation with non-inactivated serum. Ceramide phosphate also induces TNF-alpha release in J774A.1 cells, but (unlike sphingomyelin/sphingomyelinase) the level of release is not influenced by the presence or otherwise of non-inactivated serum. L. gaucho venom does not induce proliferation of J774A.1 cells and even at high concentrations it does not affect their viability. J774A.1 cells, which prior to venom treatment were elongated and clumped, round up after venom treatment, but, revert to their original morphology after incubation with fresh medium. TNF-alpha resistant MRC-5 cells and TNF-alpha sensitive MCF-7 cells are susceptible to the toxic effect of both L. gaucho venom and ceramide phosphate. The results obtained in this study demonstrate that exogenous sphingomyelin can modulate, in vitro, the release of TNF-alpha induced by L. gaucho venom in mouse macrophages. In addition, the results also indicate that ceramide phosphate and L. gaucho venom are toxic to several different cell types, via a variety of mechanisms, some, but not all, of which may involve TNF-alpha as an intermediary.  相似文献   

20.
Thymosin beta(4) (Tbeta(4)), a highly conserved peptide with immunomodulatory properties, is the major actin-sequestering peptide in mammalian cells. Recent studies have established that Tbeta(4) can accelerate wound healing in full thickness skin wounds and following burn injuries to the cornea. In the eye studies, the accelerated healing due to Tbeta(4) was accompanied by a significant reduction in polymorphonuclear leukocyte (PMN) infiltration and a several-fold decrease in interleukin-1beta (p< or =0.015) and 6-keto-prostaglandin F(1alpha) (6-keto-PGF1alpha, p< or =0.05). Given the recognized role of proinflammatory cytokines in septic shock and of extracellular F- and G-actin in the pathophysiology of multiple organ dysfunction, we have investigated the role of Tbeta(4) in sepsis. We report that an LD(50) dose of LPS (24 mg/kg) in rats resulted in a significant reduction of Tbeta(4) levels in the blood. Furthermore, administration of 100 microg of Tbeta(4) immediately following and at 2 and 4 h after an LD(50) dose of LPS (60 mg/kg) in mice significantly reduced mortality rates (p< or =0.024) and lowered blood levels of a number of inflammatory cytokines, eicosanoids, and other molecules that are highly elevated following endotoxin administration. In studies in human subjects given low doses of endotoxin (4 ng/kg LPS) and in patients with septic shock, we have also observed significant decreases in blood levels of Tbeta(4). The rapid disappearance of Tbeta(4) in the blood following LPS administration or during septic shock suggests that Tbeta(4) may be involved in early events leading to activation of the inflammatory cascade and ultimately the clinical sequelae of sepsis. The results of this study indicate that Tbeta(4) may have utility in the clinic in the treatment of septic shock and in syndromes associated with actin toxicities.  相似文献   

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