Morphological and biochemical characterization of macrophages activated by carrageenan and lipopolysaccharide in vivo.
ABSTRACT Macrophages are able to recognize, internalize and destroy a large number of pathogens, thus restricting the infection until adaptive immunity is initiated. In this work our aim was to analyze the surface charge of cells activated by carrageenan (CAR) and lipopolysaccharide (LPS) through light and electron microscopy approaches as well as the release of inflammatory mediators in vitro. The ultrastuctural analysis and the light microscopy data showed that in vivo administration of CAR represents a potent inflammatory stimulation for macrophages leading to a high degree of spreading, an increase in their size, in the number of the intracellular vacuoles and membrane projections as compared to the macrophages collected from untreated animals as well as mice submitted to LPS. Our data demonstrated that CAR stimulated-macrophages displayed a remarkable increase in nitric oxide production and PGE2 release as compared to the cells collected from non-stimulated and stimulated mice with LPS in vivo. On the other hand, non-stimulated macrophages as well as macrophages stimulated by LPS produce almost the same quantities of TNF-alpha, while in vivo stimulation by CAR leads to a 30-40% increase of cytokine release in vitro compared to the other groups. In conclusion, our morphological and biochemical data clearly showed that in vivo stimulation with CAR induces a potent inflammatory response in macrophages representing an interesting model to analyze inflammatory responses.
- SourceAvailable from: Michel Salzet[show abstract] [hide abstract]
ABSTRACT: The proprotein convertase 1/3 is expressed in the regulated secretory pathway of neural and endocrine cells. Its major function is in the post-translational processing and activation of precursor proteins. The PC1/3 knock-out (KO) mouse model has allowed us to elucidate its physiological functions in studies focused primarily on neuroendocrine tissues. However, PC1/3 is also expressed in cells of the immune system, mainly in macrophages. The present study explores the effects of innate immune challenge in the PC1/3 KO mouse. PC1/3 KO mice have an enlarged spleen with marked disorganization of the marginal zone and red pulp. Immunohistochemical studies using various markers demonstrate a depletion of dendritic cells in PC1/3 KO spleens. When challenged with lipopolysaccharide, PC1/3 KO mice are more susceptible to septic shock than wild-type controls or other PC KO mice, such as PC2 and PC7 null mice. Plasma levels of proinflammatory cytokines (IL-6, IL-1β, and TNF-α) were very significantly elevated in PC1/3 KO mice, consistent with a hypercytokinemia, i.e. indicative of a major systemic uncontrolled inflammatory response or cytokine storm. Peritoneal macrophages isolated from PC1/3 KO mice also demonstrate elevated cytokine secretion when treated with LPS. Electron micrographs show morphological features indicating a prolonged activation of these cells following LPS stimulation. We also present evidence that the proinflammatory T(h)1 pathway is dominant in the PC1/3 KO mouse model. We conclude that aside from its important role in neuroendocrine functions PC1/3 also has an important role in the regulation of the innate immune system, most likely through the regulation of cytokine secretion in macrophages.Journal of Biological Chemistry 03/2012; 287(18):14703-17. · 4.65 Impact Factor
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ABSTRACT: ETHNOPHARMACOLOGICA RELEVANCE: ]The seeds of Brucea javanica (L.) Merr. (Yadanzi in Chinese) have been used for the treatment of inflammation, dysentery, malaria, and cancer in Chinese traditional medicine. However, the anti-inflammatory mechanism of B. javanica has not been fully elucidated.This study examined the anti-inflammatory activity of ethyl acetate fraction of the seeds of B. javanica (EA-BJ) in vitro and in vivo. MATERIALS AND METHODS: The anti-inflammatory activity of EA-BJ and its ability to modulate the production of NO, PGE2, TNF-α, IL-1β, IL-6 and IL-10 inflammatory mediators in lipopolysaccharide-activated RAW 264.7 macrophage were evaluated. Moreover, the anti-inflammatory activity of EA-BJ was also in vivo assayed by carrageenan induced paw edema in mice. RESULTS: In vitro assays showed remarkable anti-inflammatory activity of EA-BJ, through the inhibition of production of NO, PGE2, TNF-α, IL-1β and IL-6 inflammatory mediators and induction of production of IL-10 anti-inflammatory cytokine. In vivo assays showed anti-inflammatory activity for decrement of the paw edema in carrageenan induced paw edema test. CONCLUSION: The results obtained in vitro and in vivo showed that possible anti-inflammatory effects of EA-BJ may be attributed to inhibition pro-inflammatory mediators production, NO, PGE2, TNF-α, IL-1β and IL-6 and to increase production of IL-10 anti-inflammatory cytokine. The seeds of B. javanica may thus prove beneficial in the treatment of inflammatory diseases.Journal of ethnopharmacology 03/2013; · 2.32 Impact Factor
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ABSTRACT: Introduction: There is a pressing need for research leading to the development of new effective drugs with lower side effects and more efficacy for treating inflammatory bowel disease (IBD). The analgesic and anti-inflammatory properties of 5-Hydroxytryptamine (5-HT)-3 receptor antagonists have been shown in in vivo and in vitro studies. The present study was designed to investigate the effects of tropisetron, a 5-HT3 receptor antagonist, on an immune-based animal model of IBD. Methods: In the present study, the trinitrobenzenesulfonic acid (TNBS) model of colitis in the rat was used. Two hours after induction of colitis in rats, tropisetron (2 mg/kg), dexamethasone (1 mg/kg), meta-chlorophenylbiguanide (mCPBG, 5 mg/kg), a 5-HT3 receptor agonist, or tropisetron + mCPBG were intraperitoneally (i.p.) administrated for 6 days. Animals were then sacrificed; macroscopic, histological, biochemical (myeloperoxidase [MPO]) assessments and ELISA test (tumor necrosis factor-alpha, interleukin-6 and interleukin-1 beta) were performed on distal colon samples. Results: Tropisetron or dexamethasone treatment significantly reduced macroscopic and microscopic colonic damages. In addition, a significant reduction in MPO activity and colonic levels of inflammatory cytokines was seen. The beneficial effects of tropisetron were antagonized by concurrent administration of mCPBG. Conclusion: The present study indicates that the protective effects of tropisetron on TNBS-induced colitis can be mediated by 5-HT3 receptors.BioImpacts : BI. 01/2013; 3(4):169-76.