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LPS-induced Increase (LPS-induce + increase)

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Medical Sciences	100%

Selected Abstracts

Augmentation of endogenous cannabinoid tone modulates lipopolysaccharide-induced alterations in circulating cytokine levels in rats

IMMUNOLOGY, Issue 2 2008
Michelle Roche
Summary The endogenous cannabinoid system plays an important role in regulating the immune system. Modulation of endogenous cannabinoids represents an attractive alternative for the treatment of inflammatory disorders. This study investigated the effects of URB597, a selective inhibitor of fatty acid amide hydrolase (FAAH), the enzyme catalysing degradation of the endogenous cannabinoid anandamide, and AM404, an inhibitor of anandamide transport, on lipopolysaccharide (LPS)-induced increases in plasma cytokine levels in rats. Both URB597 and AM404 potentiated the LPS-induced increase in plasma tumour necrosis factor-, (TNF-,) levels. The peroxisome proliferator-activated receptor , (PPAR,) antagonist, GW9662, attenuated the AM404-induced augmentation of TNF-, levels. Furthermore, the selective cannabinoid CB1 and CB2 receptor antagonists, AM251 and AM630 respectively, and the transient receptor potential vanilloid receptor-1 (TRPV1) antagonist, SB366791, reduced LPS-induced TNF-, plasma levels both alone and in combination with AM404. In contrast, AM404 inhibited LPS-induced increases in circulating interleukin-1, (IL-1,) and IL-6. AM251 attenuated the immunosuppressive effect of AM404 on IL-1,. None of the antagonists altered the effect of AM404 on LPS-induced IL-6. Moreover, AM251, AM630 and SB366791, administered alone, inhibited LPS-induced increases in plasma IL-1, and IL-6 levels. In conclusion, inhibition of endocannabinoid degradation or transport in vivo potentiates LPS-induced increases in circulating TNF-, levels, an effect which may be mediated by PPAR, and is also reduced by pharmacological blockade of CB1, CB2 and TRPV1. The immunosuppressive effect of AM404 on IL-1, levels is mediated by the cannabinoid CB1 receptor. Improved understanding of endocannabinoid-mediated regulation of immune function has fundamental physiological and potential therapeutic significance. [source]

Influence of progesterone on myometrial contractility in pregnant mice treated with lipopolysaccharide

JOURNAL OF OBSTETRICS AND GYNAECOLOGY RESEARCH (ELECTRONIC), Issue 6 2007
Hiroshi Anbe
Abstract Aim:, To evaluate the effect of progesterone on interleukin (IL)-6, prostaglandin (PG) E2 and nitric oxide (NO) metabolite (NOx) production and contractile activity by NO in pregnant mice treated with lipopolysaccharide (LPS). Methods:, Pregnant C57BL mice on day 14 of gestation were killed 6 h after i.p. injection of LPS (400 ,g/kg) or vehicle. Progesterone (2 mg) was subcutaneously injected 2 h before LPS treatment. Uterine rings were equilibrated in Krebs-Henseleit solution (37°C) bubbled with 20% O2 and 5% CO2 (pH 7.4) for sampling and isometric tension recording. IL-6, PGE2 and NOx productions were measured from the bathing solution. Changes in spontaneous contractile activity in response to cumulative concentrations of l -arginine, diethylamine/nitric oxide (DEA/NO, the NO donor), and 8-bromo-cGMP (8-br-cGMP) were compared. Integral contractile activity over 10 min after each concentration was calculated and expressed as percentage change from basal activity. Statistical analyses were performed using one-way anova followed by Dunnett's test (significance was defined as P < 0.05). Results:, Interleukin-6 (34.7 ± 6.0 pg/g tissue), PGE2 (66.8 ± 6.7 pg/g tissue) and NOx (51.0 ± 5.4 pmol/2 mL/g wet tissue) production were significantly stimulated by LPS treatment (138.2 ± 23.2, 147.0 ± 29.0, 98.6 ± 16.2, respectively; P < 0.05). l -arginine, DEA/NO and 8-br-cGMP concentration-dependently inhibited spontaneous contractions in uterine rings both in LPS-treated and -untreated animals. Treatment with LPS significantly attenuated the maximal inhibition induced by l -arginine, DEA/NO and 8-br-cGMP in uterine rings from pregnant mice. Progesterone significantly decreased the levels of IL-6 production (74.9 ± 12.1, P < 0.05), but not PGE2 and NOx production, and contractile responses by l -arginine, DEA/NO and 8-br-cGMP. Conclusions:, The administration of LPS is associated with increases in IL-6, PGE2 and NO, and these increases may or may not have a role to play in LPS-induced preterm labor. Progesterone reduced the LPS-induced increase in IL-6 production and this may be one of the ways that progesterone reduces the risk of preterm labor. [source]

Eugenosedin-A amelioration of lipopolysaccharide-induced up-regulation of p38 MAPK, inducible nitric oxide synthase and cyclooxygenase-2

JOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 6 2007
Kuo-Ping Shen
In this study, we investigate the protective effects of eugenosedin-A on p38 mitogen-activated protein kinase (MAPK), inflammatory nitric oxide (NO) and cyclooxygenase-2 (COX-2) pathways in a rat model of endotoxin shock. Rats were pretreated with eugenosedin-A, trazodone, yohimbine (1 mg kg,1, i.v.), aminoguanidine or ascorbic acid (15 mg kg,1, i.v.) 30 min before endotoxin challenge. Endotoxaemia was induced by a single i.v. injection of lipopolysaccharide (LPS, 10 mg kg,1). In rats not treated with eugenosedin-A, LPS increased plasma concentrations of NO and prostaglandin E2 (PGE2), and levels of p38 MAPK, inducible NO synthase (iNOS) and COX-2 proteins in the liver, lung, aorta and lymphocytes. In the pre-treated rats, eugenosedin-A not only inhibited the LPS-induced NO and PGE2 levels but also attenuated the LPS-induced increase in p38 MAPK and iNOS levels in the liver, aorta and lymphocytes. Eugenosedin-A also reduced LPS-induced COX-2 proteins in the aorta and lymphocytes. Likewise, aminoguanidine, ascorbic acid, yohimbine and trazodone were also found to decrease NO and PGE2 concentrations after endotoxin challenge. While aminoguanidine and ascorbic acid also attenuated the LPS-induced increase in p38 MAPK, iNOS and COX-2 proteins in the aorta and lymphocytes, trazodone and yohimbine inhibited only the increase in p38 MAPK, iNOS and COX-2 proteins in lymphocytes. Finally, eugenosedin-A (10,10 -10,8 M) significantly inhibited the biphasic response induced by hydrogen peroxide (10,6 -3 × 10,5 M) in rat denudated aorta. Taken together, the results of this study indicate that eugenosedin-A, as well as ascorbic acid, can attenuate free-radical-mediated aortic contraction and relaxation. It may therefore be able to reduce the damage caused by septic shock by inhibiting formation of p38 MAPK, iNOS, COX-2 and free radicals. [source]

In Vivo and In Vitro Evidence of the Involvement of CXCL1, a Keratinocyte-Derived Chemokine, in Equine Laminitis

JOURNAL OF VETERINARY INTERNAL MEDICINE, Issue 5 2009
R.R. Faleiros
Background: C-X-C motif ligand 1 (CXCL1) is an important chemokine of epithelial origin in rodents and humans. Objectives: To assess in vivo and in vitro the regulation of CXCL1 in equine laminitis. Animals: Twenty adult horses. Methods: Real-time quantitative polymerase chain reaction (PCR) was used to assess expression of CXCL1 in samples of laminae, liver, skin, and lung from the black walnut extract (BWE) model of laminitis, and in cultured equine epithelial cells (EpCs). Tissue was obtained from control animals (CON, n = 5), and at 1.5 hours (early time point [ETP] group, n = 5), at the onset of leukopenia (developmental time point [DTP] group, n = 5), and at the onset of lameness (LAM group, n = 5) after BWE administration. EpCs were exposed to Toll-like/Nod receptor ligands, oxidative stress agents, and reduced atmospheric oxygen (3%). In situ PCR was used to localize the laminar cell types undergoing CXCL1 mRNA expression. Results: Increases in laminar CXCL1 mRNA concentrations occurred in the ETP (163-fold [P= .0001]) and DTP groups (21-fold [P= .005]). Smaller increases in CXCL1 expression occurred in other tissues and organs. In cultured EpCs, increases (P < .05) in CXCL1 mRNA concentration occurred after exposure to lipopolysaccharide (LPS [28-fold]), xanthine/xanthine oxidase (3.5-fold), and H2O2 (2-fold). Hypoxia enhanced the LPS-induced increase in CXCL1 mRNA (P= .007). CXCL1 gene expression was localized to laminar EpCs, endothelial cells, and emigrating leukocytes. Conclusion and Clinical Importance: These findings indicate that CXCL1 plays an early and possibly initiating role in neutrophil accumulation in the BWE laminitis model, and that laminar keratinocytes are an important source of this chemokine. New therapies using chemokine receptor antagonists may be indicated. [source]