leukotriene-b4 and Pleurisy

Atropa acuminata Royle Ex Lindl. has been widely used in folk medicine for several inflammatory disorders such as arthritis, asthma, conjunctivitis, encephalitis, pancreatitis, peritonitis, acute infections and neuroinflammatory disorders.. Our aim was to evaluate Atropa acuminata for its anti-inflammatory properties and to delineate its possible mechanism of action on the modulation of the inflammatory mediators.. We investigated the inhibitory action of ethanolic extract of Atropa acuminata (AAEE) on production of NO, TNF-α and IL-1β in lipopolysaccharide (LPS)-stimulated RAW264.7 cells and also assayed it for COX 1/2 and 5-LOX inhibitory activities. Next AAEE was tested in acute inflammatory animal models., carragenean induced rat paw edema, carragenean induce pleurisy in rats and vascular permeability in mice and the effects on NO, PGE2 and LTB4 production in the pleural fluid and paw exudates were evaluated. In addition the effects on leukocyte migration and exudation and vascular permeability were also observed.. Our findings summarized novel anti-inflammatory mechanisms for Atropa acuminata based on dual in vitro cyclooxygenase 1/2/ and 5-Lipoxygenase inhibitory activities and also significant downregulation of nitric oxide (NO) and pro-inflammatory cytokin (TNF-α and Il-1 β) release in LPS-stimulated RAW 246.7 macrophage cell line. In acute inflammatory models in vivo (carragenean induced edema, carragenean induced pleurisy in rats and vascular permeability in mice), AAEE exhibited an extensive diverse mechanism for anti-inflammatory properties. This was indicated on the basis of dose dependent suppression of multi targeted inflammatory mediators., NO, TNF-α and IL-1β, eicosanoids., PGE2 and leukotrienes., LTB4 along with significantly decreased leucocyte migration, exudation and decreased vascular permeability. These effects were more potent and prolonged than traditional NSAIDS, thereby indicating fewer side effects. AAEE was found to be safe for long term administration, as confirmed by the results of acute toxicity studies and MTT assay. The complex mode of action of the herbs was attributed possibly due to the high polyphenolic, flavanol and flavonoid content present in the extracts as observed by means of quantitative screening for phytochemicals.. Our study provides scientific evidence to support the traditional anti-inflammatory uses of Atropa acuminata and is probably due to inhibitory effects on multiple inflammatory mediators which indicates a promising potential for the development of a strong anti-inflammatory agent from this plant.

Topics: Animals; Anti-Inflammatory Agents; Atropa; Capillary Permeability; Cell Line; Cyclooxygenase 1; Cyclooxygenase 2; Dinoprostone; Edema; Ethanol; Female; Inflammation Mediators; Interleukin-1beta; Leukotriene B4; Lipoxygenase; Lipoxygenase Inhibitors; Male; Membrane Proteins; Mice; Nitric Oxide; Phytotherapy; Plant Extracts; Pleurisy; Rats; Rats, Wistar; Solvents; Tumor Necrosis Factor-alpha

Several emerging lines of evidence support an anti-inflammatory role for nicotinamide and other vitamin B components. However, the mechanisms underlying their activity remain unclear. In the present study, we investigated the ability of nicotinamide to inhibit both neutrophil recruitment in IL-8-, LTB(4)- or carrageenan-induced pleurisy in mice and the rolling and adherence of neutrophils. Nicotinamide inhibited IL-8-, LTB(4)- and carrageenan-induced neutrophil migration, KC production and carrageenan-induced neutrophil rolling and adherence. We propose that the effects of nicotinamide in inhibiting neutrophil recruitment in carrageenan-induced pleurisy may be due to the ability of nicotinamide to inhibit the action of IL-8 and LTB(4), decrease KC production, and inhibit early events that regulate leukocyte migration from blood vessels into tissue.

Topics: Animals; Anti-Inflammatory Agents; Carrageenan; Cell Adhesion; Disease Models, Animal; Interleukin-8; Leukocyte Rolling; Leukotriene B4; Male; Mice; Mice, Inbred BALB C; Neutrophil Infiltration; Niacinamide; Pleurisy

5-Lipoxygenase (5-LO) is the key enzyme in the biosynthesis of pro-inflammatory leukotrienes (LTs) representing a potential target for pharmacological intervention with inflammation and allergic disorders. Although many LT synthesis inhibitors are effective in simple in vitro test systems, they frequently fail in vivo due to lack of efficacy. Here, we attempted to assess the pharmacological potential of the previously identified 5-LO inhibitor 2-(4-(biphenyl-4-ylamino)-6-chloropyrimidin-2-ylthio)octanoic acid (HZ52).. We evaluated the efficacy of HZ52 in vivo using carrageenan-induced pleurisy in rats and platelet-activating factor (PAF)-induced lethal shock in mice. We also characterized 5-LO inhibition by HZ52 at the cellular and molecular level in comparison with other types of 5-LO inhibitor, that is, BWA4C, ZM230487 and hyperforin.. HZ52, 1.5 mg·kg⁻¹ i.p., prevented carrageenan-induced pleurisy accompanied by reduced LTB(4) levels and protected mice (10 mg·kg⁻¹, i.p.) against PAF-induced shock. Detailed analysis in cell-based and cell-free assays revealed that inhibition of 5-LO by HZ52 (i) does not depend on radical scavenging properties and is reversible; (ii) is not impaired by an increased peroxide tone or by elevated substrate concentrations; and (iii) is little affected by the cell stimulus or by phospholipids, glycerides, membranes or Ca²⁺.. HZ52 is a promising new type of 5-LO inhibitor with efficacy in vivo and with a favourable pharmacological profile. It possesses a unique 5-LO inhibitory mechanism different from classical 5-LO inhibitors and seemingly lacks the typical disadvantages of former classes of LT synthesis blockers.

Topics: Animals; Anti-Inflammatory Agents; Arachidonate 5-Lipoxygenase; Caprylates; Carrageenan; Leukotriene B4; Lipoxygenase Inhibitors; Male; Mice; Neutrophils; Nuclear Envelope; Platelet Activating Factor; Pleurisy; Protein Transport; Pyrimidines; Rats; Rats, Wistar; Shock

Although proteinase-activated receptor (PAR)-4 has been implicated in inflammation, its role in regulating eosinophil recruitment in response to chemoattractants has not yet been demonstrated. To investigate the contribution of proteinases and PAR-4 activation to eosinophil migration in response to eotaxin-1 or leukotriene B(4) (LTB(4)), the effects of aprotinin or PAR-4 antagonist trans-cinnamoyl-YPGKF-NH(2) (tcY-NH(2)) on eosinophil migration induced by these chemoattractants were investigated.. BALB/c mice were pretreated with aprotinin or tcY-NH(2) (30 μg/mouse) prior to intrapleural injection of LTB(4) or eotaxin-1 and the number of infiltrating eosinophils was determined 48 h later.. Aprotinin (1 mg/kg) inhibited eosinophil recruitment induced by eotaxin-1 (p < 0.01), but not that induced by LTB(4). Moreover, tcY-NH(2) treatment inhibited eosinophil recruitment in response to eotaxin-1 (p < 0.01 by ANOVA/Tukey post-test).. These data suggest that aprotinin-inhibited proteinases participate in eosinophil migration induced by eotaxin-1 and that PAR-4 activation plays an important role in regulating this migration.

Topics: Animals; Aprotinin; Cell Movement; Chemokine CCL11; Cinnamates; Eosinophils; Leukotriene B4; Male; Mice; Mice, Inbred BALB C; Oligopeptides; Ovalbumin; Pleural Cavity; Pleurisy; Receptors, Proteinase-Activated

Myrtucommulone (MC), a nonprenylated acylphloroglucinol contained in the leaves of myrtle (Myrtus communis), has been reported to suppress the biosynthesis of eicosanoids by inhibition of 5-lipoxygenase and cyclooxygenase-1 in vitro and to inhibit the release of elastase and the formation of reactive oxygen species in activated polymorphonuclear leukocytes. Here, in view of the ability of MC to suppress typical proinflammatory cellular responses in vitro, we have investigated the effects of MC in in vivo models of inflammation. MC was administered to mice intraperitoneally, and paw edema and pleurisy were induced by the subplantar and intrapleural injection of carrageenan, respectively. MC (0.5, 1.5, and 4.5 mg/kg i.p.) reduced the development of mouse carrageenan-induced paw edema in a dose-dependent manner. Moreover, MC (4.5 mg/kg i.p. 30 min before and after carrageenan) exerted anti-inflammatory effects in the pleurisy model. In particular, 4 h after carrageenan injection in the pleurisy model, MC reduced: 1) the exudate volume and leukocyte numbers; 2) lung injury (histological analysis) and neutrophil infiltration (myeloperoxidase activity); 3) the lung intercellular adhesion molecule-1 and P-selectin immunohistochemical localization; 4) the cytokine levels (tumor necrosis factor-alpha and interleukin-1beta) in the pleural exudate and their immunohistochemical localization in the lung; 5) the leukotriene B(4), but not prostaglandin E(2), levels in the pleural exudates; and 6) lung peroxidation (thiobarbituric acid-reactant substance) and nitrotyrosine and poly (ADP-ribose) immunostaining. In conclusion, our results demonstrate that MC exerts potent anti-inflammatory effects in vivo and offer a novel therapeutic approach for the management of acute inflammation.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Blotting, Western; Carrageenan; Cyclooxygenase 2; Cytokines; Dinoprostone; Edema; Foot; Immunohistochemistry; Intercellular Adhesion Molecule-1; Interleukin-1beta; Leukotriene B4; Lipid Peroxidation; Male; Mice; Myrtus; P-Selectin; Peroxidase; Phloroglucinol; Pleurisy; Thiobarbituric Acid Reactive Substances; Tumor Necrosis Factor-alpha

We previously showed that, in vitro, hyperforin from St. John's wort (Hypericum perforatum) inhibits 5-lipoxygenase (5-LO), the key enzyme in leukotriene biosynthesis. Here, we demonstrate that hyperforin possesses a novel and unique molecular pharmacological profile as a 5-LO inhibitor with remarkable efficacy in vivo. Hyperforin (4 mg/kg, i.p.) significantly suppressed leukotriene B(4) formation in pleural exudates of carrageenan-treated rats associated with potent anti-inflammatory effectiveness. Inhibition of 5-LO by hyperforin, but not by the iron-ligand type 5-LO inhibitor BWA4C or the nonredox-type inhibitor ZM230487, was abolished in the presence of phosphatidylcholine and strongly reduced by mutation (W13A-W75A-W102A) of the 5-LO C2-like domain. Moreover, hyperforin impaired the interaction of 5-LO with coactosin-like protein and abrogated 5-LO nuclear membrane translocation in ionomycin-stimulated neutrophils, processes that are typically mediated via the regulatory 5-LO C2-like domain. Together, hyperforin is a novel type of 5-LO inhibitor apparently acting by interference with the C2-like domain, with high effectiveness in vivo.

Topics: Animals; Arachidonate 5-Lipoxygenase; Binding Sites; Bridged Bicyclo Compounds; Carrageenan; Cells, Cultured; Diglycerides; Humans; Hypericum; Leukotriene B4; Lipoxygenase Inhibitors; Male; MAP Kinase Signaling System; Microfilament Proteins; Neutrophils; Oxidation-Reduction; Phloroglucinol; Phospholipids; Pleurisy; Protein Structure, Tertiary; Protein Transport; Rats; Rats, Wistar; Terpenes; Tryptophan

Wilbrandia ebracteata (WE), a Brazilian medicinal plant used in folk medicine for the treatment of rheumatic diseases, displays anti-inflammatory properties and constitutes a rich source of cucurbitacins and cucurbitacin-related compounds. The current study investigated the potential anti-inflammatory properties of Dihydrocucurbitacin B (DHCB), a cucurbitacin-derived compound isolated from roots of WE, in some in vivo and in vitro experimental models. Intraperitoneal treatment of mice with DHCB reduced both carrageenan-induced paw edema (0.3, 1 and 3 mg/kg caused inhibitions of 26, 44 and 56 % at 2 h after stimulation, respectively) and pleurisy (10 mg/kg inhibited leukocyte numbers and LTB(4) levels in the pleural fluid by 51 and 75% at 6 h after cavity challenge, respectively). In vitro, DHCB (up to 10 microg/mL) failed to modify LTB(4) production by human neutrophils or PGE(2) production by COS-7 cells transfected with COX-1, but PGE(2) production by COX-2 transfected COS-7 cells was markedly inhibited (by 72%). The levels of COX-1 or COX-2 proteins in IL-1alpha-stimulated NIH3T3 cells were unaffected by DHCB. The results corroborate the potential anti-inflammatory properties ascribed to W. ebracteata Cogn. in folk medicine and suggest that they might be attributed, at least in part, to the capacity of one of this plants main constituents, DHCB, to inhibit COX-2 activity (but not its expression) during inflammation.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Carrageenan; Chlorocebus aethiops; COS Cells; Cucurbitaceae; Cyclooxygenase 1; Cyclooxygenase 2 Inhibitors; Cyclooxygenase Inhibitors; Dinoprostone; Edema; Humans; Leukotriene B4; Male; Methylene Chloride; Mice; Neutrophils; NIH 3T3 Cells; Plant Roots; Pleurisy; Solvents; Triterpenes

4-(2',4'- Difluorobiphenyl-4-yl)-2-methylbutyric acid (deoxoflobufen, VUFB 19053, CAS 847475-35-8) has been developed as a new omega-biphenyl-alkanoic acid and studied in comparison with the racemic form of 4-(2',4'-difluorobiphenyl-4-yl)-2-methyl-4-oxobutanoic acid (flobufen, CAS 112344-52-2). The compounds were tested in a series of models including acute inflammation induced by carrageenan, adjuvant arthritis, in vitro inhibition of the leuktotriene B4 (LTB4) production, reaction of the graft versus the host (GVHR), production of specific antibodies against ovalbumin, peritoneal exudate formation induced by thioglycollate and phagocytosis of thioglycollate-stimulated mouse peritoneal macrophages. Deoxoflobufen exhibited strong anti-inflammatory, antiarthritic and immunomodulatory effects in most of the performed tests. Anti-inflammatory and antiarthritic effects are fully comparable with those of flobufen, however, the compound is less toxic and has apparently stronger immunomodulating effects.

Topics: Animals; Anti-Inflammatory Agents; Antibody Formation; Area Under Curve; Arthritis, Experimental; Biphenyl Compounds; Butyrates; Carrageenan; Cell Adhesion; Exudates and Transudates; Female; Graft vs Host Disease; Hypersensitivity, Delayed; Inflammation; Leukotriene B4; Macrophages; Mice; Ovalbumin; Peritonitis; Phagocytosis; Pleurisy; Rats; Structure-Activity Relationship; Thioglycolates

Acute inflammation can be considered in terms of a series of checkpoints where each phase of cellular influx, persistence, and clearance is controlled by endogenous stop and go signals. It is becoming increasingly apparent that in addition to initiating the inflammatory response, eicosanoids may also mediate resolution. This suggests there are two phases of arachidonic acid release: one at onset for the generation of proinflammatory eicosanoids and one at resolution for the synthesis of proresolving eicosanoids. What is unclear is the identity of the phospholipase (PLA2) isoforms involved in this biphasic release of arachidonic acid. We show here that type VI iPLA2 drives the onset of acute pleurisy through the synthesis of PGE2, LTB4, PAF, and IL-1beta. However, during resolution there is a switch to a sequential induction of first sPLA2 (types IIa and V) that mediates the release of PAF and lipoxin A4, which, in turn, are responsible for the subsequent induction of type IV cPLA2 that mediates the release of arachidonic acid for the synthesis of proresolving prostaglandins. This study is the first of its kind to address the respective roles of PLA2 isoforms in acute resolving inflammation and to identify type VI iPLA2 as a potentially selective target for the treatment of inflammatory diseases.

Topics: Acute Disease; Animals; Arachidonic Acid; Carrageenan; Cells, Cultured; Convalescence; Corticosterone; Cyclooxygenase 2; Disease Progression; Enzyme Induction; Epithelial Cells; Fibroblasts; Group II Phospholipases A2; Group IV Phospholipases A2; Group V Phospholipases A2; Group VI Phospholipases A2; Interleukin-1; Isoenzymes; Leukotriene B4; Lipoxins; Macrophages; Male; Phospholipases A; Phospholipases A2; Platelet Activating Factor; Pleurisy; Prostaglandin-Endoperoxide Synthases; Rats; Rats, Wistar

Eosinophils are important inflammatory cells in allergic diseases. In the present study, we have investigated the effects of CCL22 on the recruitment of eosinophils in vivo and in vitro. CCL22 induced a dose- and time-dependent recruitment of eosinophils into the pleural cavity of mice, and this was dependent on the release of platelet-activating factor (PAF) and subsequent generation of CCL11. However, in an allergic pleurisy model, an anti-CCL22 polyclonal antibody given during sensitization or before challenge had no significant effect on eosinophil recruitment. CCL22 did not induce eosinophil chemotaxis in vitro but was able to induce eosinophil degranulation in vitro and in vivo. In conclusion, we show that although exogenously added CCL22 may induce eosinophil migration in vivo via release of PAF and CCL11 (eotaxin), endogenous production of CCL22 does not drive eosinophil migration during allergic inflammation. However, CCL22 may be an important activator of eosinophils once these cells have migrated into tissue.

Topics: Animals; Antibodies; Cell Degranulation; Chemokine CCL11; Chemokine CCL22; Chemokines, CC; Chemotactic Factors, Eosinophil; Chemotaxis; Eosinophils; Hypersensitivity; Leukotriene B4; Male; Mice; Mice, Inbred BALB C; Mice, Knockout; Platelet Membrane Glycoproteins; Pleurisy; Receptors, Cell Surface; Receptors, G-Protein-Coupled

The recently identified histamine receptor, H4, was shown to be primarily expressed on leukocytes and has been implicated in the activation of lymphocytes, eosinophils, and mast cells in vitro. Its function in vivo, however, has not yet been characterized. We present evidence for a critical role of H4 receptor in the mast cell-dependent recruitment of neutrophils. Mice injected with zymosan into the pleural cavity developed massive neutrophilia within hours after challenge. Neutrophilia was dose-dependently reduced when mice were pretreated with thioperamide, a known H(3/4) receptor antagonist, whereas H1 and H2 receptor antagonists lacked efficacy. Similarly, a 70 to 80% reduction in neutrophils in the pleural cavity compared with wild-type animals was noted in mice lacking mast cells (W/W(v) mice); mice deficient in MyD88 (MyD88(-/-)); a critical component of the signaling cascade of the major receptor for zymosan, toll-like receptor 2 (TLR2); or in mice pretreated with a functionally antagonistic anti-TLR2 antibody. The residual 20% neutrophil infiltration seen in mast cell-deficient and MyD88(-/-) mice was not further reduced by thioperamide. Neutrophilia was completely restored by transferring wild-type bone marrow-derived mast cells into MyD88(-/-) or W/W(v) mice. Interestingly, when neutrophilia was evoked by carrageenan injection, mast cell depletion and thioperamide had no effect. Various inflammatory mediators were detectable in the pleural cavity of zymosan-challenged mice. Upon pretreatment with thioperamide, reduced levels of the neutrophil chemoattractant leukotriene B4 were observed, providing a mechanistic explanation for the prevention of neutrophilia by H4 receptor antagonism.

Topics: Animals; Bone Marrow Cells; Carrageenan; Cimetidine; Cytokines; Dose-Response Relationship, Drug; Enzyme-Linked Immunosorbent Assay; Histamine Antagonists; Histamine H1 Antagonists; Histamine H2 Antagonists; Histamine Release; Leukotriene B4; Mast Cells; Mice; Mice, Inbred BALB C; Neutrophil Infiltration; Piperidines; Pleurisy; Pyrilamine; Receptors, G-Protein-Coupled; Receptors, Histamine; Receptors, Histamine H3; Receptors, Histamine H4; Zymosan

The understanding of the mechanisms underlying eosinophil recruitment in vivo may aid in the development of novel strategies for the treatment of allergic disorders. In this study, we investigated the role of chemokines in the cascade of events leading to eosinophil recruitment in a stem cell factor (SCF)- and leukotriene B(4) (LTB(4))-dependent allergic pleurisy model in mice. The intrapleural administration of the eosinophil-active chemokines eotaxin, RANTES, and macrophage-inflammatory protein 1alpha (MIP-1alpha) induced a time- and dose-dependent eosinophil recruitment. Pretreatment with anti-eotaxin, but not anti-RANTES or anti-MIP-1alpha, blocked the recruitment of eosinophils following Ag challenge of sensitized animals, and significant eotaxin immunoreactivity was detected in the pleural cavity of these animals. Similarly, only the anti-eotaxin inhibited the eosinophil recruitment induced by injection of SCF in naive animals. However, blockade of SCF did not inhibit the release of eotaxin after Ag challenge of sensitized mice. Akin to its effects on SCF and in the allergic reaction, eotaxin-induced eosinophil recruitment was blocked by the LTB(4) receptor antagonist CP105696. Nevertheless, SCF, but not eotaxin, appeared to regulate the endogenous release of LTB(4) after Ag challenge. Finally, we show that low doses of eotaxin synergized with LTB(4) to induce eosinophil recruitment in the pleural cavity. Overall, the present results show that eotaxin and SCF-induced LTB(4) cooperate to induce eosinophil recruitment into sites of allergic inflammation. Cooperation between inflammatory mediators must be an important phenomenon in vivo, explaining both the ability of lower concentrations of mediators to induce a full-blown functional response and the effectiveness of different strategies at inhibiting these responses.

Topics: Animals; Cell Movement; Chemokine CCL11; Chemokine CCL3; Chemokine CCL4; Chemokine CCL5; Chemokines, CC; Cytokines; Injections, Intraperitoneal; Injections, Subcutaneous; Leukotriene B4; Macrophage Inflammatory Proteins; Male; Mice; Mice, Inbred BALB C; Ovalbumin; Pleura; Pleurisy; Receptors, Chemokine; Respiratory Hypersensitivity; Stem Cell Factor

The effect of four macrolide antibiotics (roxithromycin, clarithromycin, erythromycin, and azithromycin) on the generation of some mediators and cytokines involved in the inflammatory process has been studied both in vivo and in vitro. Rat carrageenin pleurisy was used as a model of acute inflammation, and the macrolides were administered (10, 20, and 40 mg/kg p.o.) 1 h before the carrageenin challenge. Exudate volume and leukocyte accumulation were both dose-dependently reduced by roxithromycin, clarithromycin and erythromycin in either normal or adrenalectomized animals. Furthermore, in normal rats, prostaglandin (PG)E(2), nitrate plus nitrite, and tumor necrosis factor-alpha levels in pleural exudate were significantly reduced by these macrolides. Roxithromycin appeared more effective than erythromycin and clarithromycin, whereas azithromycin only slightly affected the inflammatory reaction. None of the macrolides were able to modify leukotriene B(4) exudate levels. In vitro experiments have shown that the four macrolides (5-80 microM) reduced in a concentration-dependent manner the production of 6-keto-PGF(1alpha), NO(2)(-), tumor necrosis factor-alpha, interleukin-1beta, and interleukin-6 by lipopolysaccharide-stimulated J774 macrophages. In J774 cells, the inhibition of 6-keto-PGF(1alpha) and NO(2)(-) production by roxithromycin and erythromycin was not dependent on direct inhibition of cyclooxygenase-2 and inducible nitric oxide synthase activity because it appears to be related to the inhibition of cyclooxygenase-2 and inducible nitric oxide synthase protein expression. In conclusion, the present study shows that macrolide antibiotics have anti-inflammatory activity, which likely depends on their ability to prevent the production of proinflammatory mediators and cytokines, and suggest that these agents, particularly roxithromycin, can exert therapeutic effects independently of their antibacterial activity.

Topics: 6-Ketoprostaglandin F1 alpha; Adrenalectomy; Anesthesia; Animals; Anti-Bacterial Agents; Anti-Inflammatory Agents; Azithromycin; Carrageenan; Cell Line; Clarithromycin; Cyclooxygenase 2; Cytokines; Dinoprostone; Dose-Response Relationship, Drug; Erythromycin; Inflammation Mediators; Isoenzymes; Leukotriene B4; Macrophages; Mice; Nitrates; Nitric Oxide; Nitric Oxide Synthase; Nitric Oxide Synthase Type II; Nitrites; Pleurisy; Prostaglandin-Endoperoxide Synthases; Rats; Roxithromycin; Time Factors; Tumor Necrosis Factor-alpha

The understanding of the mechanisms underlying eosinophil migration into tissue is an essential step in the development of novel therapies aimed at treating allergic diseases where eosinophil recruitment and activation are thought to play an essential role. In this study, we have examined the effects of the in vivo administration of stem cell factor (SCF) on eosinophil recruitment and tested whether endogenous SCF was involved in mediating eosinophil recruitment in response to Ag challenge in sensitized mice. The intrapleural injection of SCF induced a time- and concentration-dependent recruitment of eosinophils in mice. In allergic mice, SCF message was expressed early after Ag challenge and returned to baseline levels after 8 h. In agreement with the ability of SCF to induce eosinophil recruitment and its expression in the allergic reaction, an anti-SCF polyclonal Ab abrogated eosinophil recruitment when given before Ag challenge. SCF increased the levels of leukotriene B4 (LTB4) in the pleural cavity of mice and an LTB4 receptor antagonist, CP105,696, abrogated the effects of SCF on eosinophil recruitment. Similarly, recruitment of eosinophils in the allergic reaction was virtually abolished by CP105,696. Together, our data favor the hypothesis that the local release of SCF following Ag challenge may activate and/or prime mast cells for IgE-mediated release of inflammatory mediators, especially LTB4. The mediators released in turn drive the recruitment of eosinophils. Inhibition of the function of SCF in vivo may reduce the migration of eosinophils to sites of allergic inflammation and may, thus, be a relevant principle in the treatment of allergic diseases.

Topics: Animals; Antigens; Cell Movement; Eosinophils; Injections; Leukotriene B4; Male; Mice; Mice, Inbred BALB C; Ovalbumin; Pleura; Pleurisy; Respiratory Hypersensitivity; Stem Cell Factor

Symmetrical bis(quinolylmethoxyphenyl)alkylcarboxylic acids were investigated as inhibitors of leukotriene biosynthesis and 4, 4-bis(4-(2-quinolylmethoxy)phenyl)pentanoic acid sodium salt (47.Na) met our design parameters for a drug candidate (ABT-080). This compound was readily synthesized in three steps from commercially available diphenolic acid. Against intact human neutrophils, 47.Na inhibited ionophore-stimulated LTB(4) formation with an IC(50) = 20 nM. In zymosan-stimulated mouse peritoneal macrophages producing both LTC(4) and PGE(2), 47.Na showed 9000-fold selectivity for inhibition of LTC(4) (IC(50) = 0.16 nM) over PGE(2) (IC(50) = 1500 nM). Preliminary pharmacokinetic evaluation in rat and cynomolgus monkey demonstrated good oral bioavailability and elimination half-lives of 9 and 5 h, respectively. Pharmacological evaluation of leukotriene inhibition with oral dosing was demonstrated in a rat pleural inflammation model (ED(50) = 3 mg/kg) and a rat peritoneal passive anaphylaxis model (LTB(4), ED(50) = 2.5 mg/kg; LTE(4), ED(50) = 1.0 mg/kg). In a model of airway constriction induced by antigen challenge in actively sensitized guinea pigs, 47.Na dosed orally blocked bronchoconstriction with an ED(50) = 0.4 mg/kg, the most potent activity we have observed for any leukotriene inhibitor in this model. The mode of inhibitory action of 47.Na occurs at the stage of 5-lipoxygenase biosynthesis as it blocks both leukotriene pathways leading to LTB(4) and LTC(4) but not PGH(2) biosynthesis. However, 47.Na does not inhibit 5-lipoxygenase catalysis in a broken cell enzyme assay; therefore it is likely that 47.Na acts as a FLAP inhibitor.

Topics: Administration, Oral; Anaphylaxis; Animals; Bronchoalveolar Lavage Fluid; Bronchoconstriction; Carboxylic Acids; Drug Evaluation, Preclinical; Eosinophils; Guinea Pigs; Humans; In Vitro Techniques; Leukotriene Antagonists; Leukotriene B4; Lung; Macaca fascicularis; Mice; Neutrophils; Pentanoic Acids; Peritoneum; Pleurisy; Quinolines; Rats; Structure-Activity Relationship

We evaluated the effects of a new non-steroidal anti-inflammatory drug (NSAID), d-2-[4-(3-methyl-2-thienyl)phenyl]propionic acid (M-5011), and indomethacin on the production of arachidonate metabolites and pro-inflammatory cytokines in male Sprague-Dawley rats with monosodium urate crystal (MSU)-induced pleurisy. Levels of tumor necrosis factor (TNF), interleukin (IL)-1 and IL-6 in the pleural exudate were determined by biological assays, while prostaglandin E2 (PGE2), leukotriene B4 (LTB4) and cytokine-induced chemoattractant-1 (CINC-1) levels were quantified by enzyme immunoassays. Orally administered M-5011 (5 mg/kg) decreased the pleural exudate volume at 3 and 4 hr after MSU injection. Indomethacin (10 mg/kg) decreased the volume at 3-5 hr. These drugs reduced the number of leukocytes in the pleural cavity at 6 hr. Both NSAIDs also reduced the content of PGE2 in the exudate without affecting LTB4 levels. Increased productions of both IL-6 and CINC-1 in the exudate were reduced by pretreatment with M-5011 or indomethacin, and TNF levels in the exudate were increased by pretreatment of these drugs. Thus, M-5011 inhibits the production of both IL-6 and CINC-1 at lower doses than those of indomethacin, and the inhibitory effect of M-5011 on CINC-1, but not IL-6, may partly contribute to the inhibition of leukocyte infiltration in rats with MSU-induced pleurisy.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Cell Line; Cytokines; Dinoprostone; Exudates and Transudates; Humans; Indomethacin; Leukotriene B4; Male; Phenylpropionates; Pleura; Pleural Effusion; Pleurisy; Rats; Rats, Sprague-Dawley; Uric Acid

In the present study we used IL-6 knockout mice (IL-6KO) to evaluate the role of IL-6 in the inflammatory response caused by injection of carrageenan into the pleural space. Compared with carrageenan-treated IL-6 wild-type (IL-6WT) mice, carrageenan-treated IL-6KO mice exhibited a reduced degree of pleural exudation and polymorphonuclear cell migration. Lung myeloperoxidase activity and lipid peroxidation were significantly reduced in IL-6KO mice compared with those in IL-6WT mice treated with carrageenan. Immunohistochemical analysis for nitrotyrosine and poly(A)DP-ribose polymerase revealed a positive staining in lungs from carrageenan-treated IL-6WT mice. No positive staining for nitrotyrosine or PARS was found in the lungs of the carrageenan-treated IL-6KO mice. Staining of lung tissue sections obtained from carrageenan-treated IL-6WT mice with an anti-cyclo-oxygenase-2 Ab showed a diffuse staining of the inflamed tissue. Furthermore, expression of inducible nitric oxide synthase was found mainly in the macrophages of the inflamed lungs from carrageenan-treated IL-6WT mice. The intensity and degree of the staining for cyclo-oxygenase-2 and inducible nitric oxide synthase were markedly reduced in tissue sections obtained from carrageenan-treated IL-6KO mice. Most notably, the degree of lung injury caused by carrageenan was also reduced in IL-6KO mice. Treatment of IL-6WT mice with anti-IL-6 (5 microg/day/mouse at 24 and 1 h before carrageenan treatment) also significantly attenuated all the above indicators of lung inflammation. Taken together, our results clearly demonstrate that IL-6KO mice are more resistant to the acute inflammation of the lung caused by carrageenan injection into the pleural space than the corresponding WT mice.

Topics: Animals; Carrageenan; Cells, Cultured; Cytokines; Dinoprostone; DNA Damage; Enzyme Induction; Interleukin-6; Leukotriene B4; Lung; Macrophages; Male; Malondialdehyde; Mice; Mice, Knockout; Nitrates; Nitric Oxide; Nitric Oxide Synthase; Nitric Oxide Synthase Type II; Peroxidase; Pleura; Pleurisy; Poly(ADP-ribose) Polymerases; Prostaglandin-Endoperoxide Synthases; Prostaglandins F; Tyrosine

An intrapleural injection of carrageenan in rats induced LTB4 and LTC4/D4/E4 biosynthesis, exudate formation, and cellular influx in the pleural cavity. An injection of calcium ionophore (A23187, 100 nmol) 16-18 h after carrageenan injection augmented leukotriene biosynthesis and exudate formation, but not cellular influx. The carrageenan-induced pleurisy model modifid by A23187 administration was used to study the oral effect of CGS 23885 (N-hydroxy-N-[(6-phenoxy-2H-1-benzopyran-3-yl)-methyl]urea), a potent 5-lipoxygenase (5-LO) inhibitor, on inflammatory parameters. CGS 23885 dose-dependently (1 to 30 mg/kg) inhibited the enhanced LTB4 and LTC4/D4/E4 (1 to 10 mg/kg) biosynthesis, but had no effect on enhanced exudate formation. An inhibitory effect of CGS 23885 of small magnitude on cellular influx due to carrageenan stimulation was seen at 30 mg/kg. The concentrations of CGS 23885 in the pleural fluid were dose-related, and a positive correlation (r2=0.989) between pleural fluid concentration of LTB4 and CGS 23885 was observed. The results confirm that CGS 23885 is a specific, orally active 5-LO inhibitor which can achieve concentrations in the pleural cavity sufficient to inhibit production of LTB4 and LTC4/D4/E4 in an ongoing inflammatory response.

Topics: Animals; Chromones; Disease Models, Animal; Dose-Response Relationship, Drug; Hydroxylamines; Leukotriene B4; Lipoxygenase Inhibitors; Male; Pleurisy; Rats; Rats, Sprague-Dawley

On the basis of basic screening for novel, more potent antiarthritics VUFB-16066 (4-(2',4'-difluorobiphenyl-4-yl)-2-methyl-4-oxobutanoic acid, CAS 112344-S2-2) was chosen as a compound with pronounced anti-inflammatory and immunomodulatory effects, with good gastric tolerance and relatively low toxicity. VUFB-16066 is a dual cyclooxygenase and 5-lipoxygenase inhibitor, and it suppresses alloantigen-driven cellular immune response and phagocytosis of stimulated peritoneal cells. VUFB-16066 exhibits prolonged pharmacological activity connected with its major metabolite having a very long half-life. In the model of adjuvant arthritis VUFB-16066 improves most of disease symptoms including immunopathological disturbances, which indicates possible disease-modifying activity of the drug. The beneficial antiarthritic effect of VUFB-16066 has been also confirmed in patients with rheumatoid arthritis.

Topics: Abdominal Pain; Acetic Acid; Animals; Anti-Inflammatory Agents, Non-Steroidal; Arachidonic Acid; Arthritis, Experimental; Butyrates; Carrageenan; Diclofenac; Dinoprostone; Edema; Female; Graft vs Host Reaction; Leukotriene B4; Male; Mice; Mice, Inbred C57BL; Phagocytosis; Phenylbutyrates; Pleurisy; Rats; Rats, Inbred Lew; Stomach Ulcer

Meloxicam is a new nonsteroidal anti-inflammatory drug (NSAID) derived from enolic acid. Preclinical studies have indicated that meloxicam has potent anti-inflammatory activity, together with a good gastrointestinal and renal tolerability profile. This report summarizes studies undertaken to compare meloxicam to other NSAIDs in the inhibition of the inducible cyclooxygenase (COX-2) in inflamed areas (pleurisy of the rat, peritonitis of mice) and their influence on the activity of the constitutive cyclooxygenase (COX-1) in stomach, kidney, brain, and blood. In pleurisy of the rat, meloxicam was twice as potent as tenoxicam, 3 times as potent as flurbiprofen, 8 times as potent as diclofenac, and 20 times as potent as tenidap at inhibiting prostaglandin E2 (PGE2) biosynthesis. In the peritonitis model in mice, meloxicam was approximately twice as active as piroxicam, and more than 10 times as active as diclofenac in the suppression of PGE biosynthesis. Doses of meloxicam sufficient to inhibit PGE2 biosynthesis in the pleural exudate and peritoneal exudate had no influence on leukotriene-B4 (LTB4) or leukotriene-C4 (LTC4) content. The effect of meloxicam on the PGE2 content of rat gastric juice and rat urine was weaker than that of piroxicam or diclofenac. Meloxicam was a weaker inhibitor of the increased PGE2 concentration in brain of rats and mice (induced by convulsant doses of pentetrazole) than piroxicam, diclofenac, or indomethacin. Meloxicam had a weaker effect on serum thromboxane-B2 (TXB2) concentration in rats than piroxicam or tenoxicam. The in vivo findings confirm the results of in vitro tests, conducted separately, showing that meloxicam preferentially inhibits COX-2 over COX-1. COX-2 is the inducible isoenzyme implicated in the inflammatory response, whereas COX-1 has cytoprotective effects in the gastric mucosa. Therefore, a preferential selectivity for one isoenzyme over another, as displayed by meloxicam, may have implications in the clinical setting in terms of a more favorable risk: benefit profile.

Topics: Administration, Oral; Animals; Anti-Inflammatory Agents, Non-Steroidal; Arachidonic Acid; Brain; Convulsants; Cyclooxygenase Inhibitors; Dinoprostone; Female; Gastric Juice; Inflammation; Isoenzymes; Kidney; Leukotriene B4; Male; Meloxicam; Mice; Pentylenetetrazole; Pleurisy; Rats; Stomach; Thiazines; Thiazoles

In the present study, A23187-induced pleurisy in mice was used to investigate the anti-inflammatory effect of magnolol, a phenolic compound isolated from Chinese medicine Hou p'u (cortex of Magnolia officinalis). A23187-induced protein leakage was reduced by magnolol (10 mg kg-1, i.p.), indomethacin (10 mg kg-1, i.p.) and BW755C (30 mg kg-1, i.p.). A23187-induced polymorphonuclear (PMN) leucocyte infiltration in the pleural cavity was suppressed by magnolol and BW755C, while enhanced by indomethacin. Like BW755C, magnolol reduced both prostaglandin E2 (PGE2) and leukotriene B4 (LTB4) levels in the pleural fluid of A23187-induced pleurisy, while indomethacin reduced PGE2 but increased LTB4 formation. In the rat isolated peripheral neutrophil suspension, magnolol (3.7 microM) and BW755C (10 microM) also suppressed the A23187-induced thromboxane B2 (TXB2) and LTB4 formation. These results suggest that magnolol, like BW755C, might be a dual cyclo-oxygenase and lipoxygenase inhibitor. The inhibitory effect of magnolol on the A23187-induced pleurisy is proposed to be, at least partly, dependent on the reduction of the formation of eicosanoids mediators in the inflammatory site.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Arachidonic Acid; Biphenyl Compounds; Body Fluids; Calcimycin; Dinoprostone; Disease Models, Animal; Leukotriene B4; Lignans; Mice; Mice, Inbred ICR; Plant Extracts; Pleura; Pleurisy; Proteins; Rats; Rats, Sprague-Dawley

The role of leukotriene B4 (LTB4) in leukocyte infiltration in zymosan-induced rat pleurisy was investigated by studying the effects of 5-lipoxygenase inhibitors, T-0757 and AA-861, and a cyclooxygenase inhibitor, indomethacin, on leukocyte infiltration and LTB4 levels in the inflammatory exudate of rat pleurisy induced by intrapleural injection of zymosan (20 mg/rat). T-0757 and AA-861 inhibited the infiltration of leukocytes, mainly neutrophils, 3 h after injection of zymosan at a dose of 100 mg/kg, p.o., but indomethacin did not do so at a dose of 5 mg/kg, p.o. LTB4 was detected in the exudate 1 h after zymosan injection, and its level peaked at 3 h (45.4 +/- 8.6 ng/rat) and decreased thereafter. These LTB4 levels were depressed by T-0757 and AA-861 in a dose-dependent manner. T-0757 completely prevented LTB4 production at a dose of 100 mg/kg. These observations suggest that the inhibition of leukocyte infiltration is mediated by the inhibition of LTB4 production, and that LTB4 is one of the main chemical mediators of leukocyte infiltration in zymosan-induced rat pleurisy.

Topics: Amides; Animals; Benzoquinones; Guinea Pigs; Indomethacin; Leukocytes; Leukotriene B4; Lipoxygenase Inhibitors; Male; Pleurisy; Rats; Rats, Wistar; Zymosan

A23187-induced pleurisy in the mouse was demonstrated in this study. The protein leakage, leukocyte accumulation, LTB4 and PGE2 production in the pleural cavity of mice were increased by A23187 in a dose-dependent manner. At 7.5 nmole A23187 intrapleural injection, the protein level peaked at 0.5-2 h, PMN leukocytes accumulation peaked at 3-4 h, and LTB4 and PGE2 production peaked at 0.5-1 h. In this in vivo model we investigated the anti-inflammatory effect of norathyriol, isolated from Tripterospermum lanceolatum. A23187-induced protein leakage was reduced by norathyriol (ID50 was about 30.6 mg/kg i.p.), indomethacin and BW755C. A23187-induced PMN leukocytes accumulation was suppressed by norathyriol (ID50 was about 16.8 mg/kg, i.p.) and BW755C, while enhanced by indomethacin. Like BW755C, norathyriol reduced both LTB4 and PGE2 production (ID50 was about 18.6 and 29.1 mg/kg i.p., respectively), while indomethacin reduced PGE2 but not LTB4 generation. We also demonstrated the analgesic effect of norathyriol on the acetic acid-induced writhing response. Acetic acid-induced writhing response was depressed by norathyriol (ID50 was about 27.9 mg/kg i.p.), indomethacin and ibuprofen. These results suggest that norathyriol, like BW755C, might be a dual, yet weak, cyclooxygenase and lipoxygenase pathway blocker. The inhibitory effect of norathyriol on the A23187-induced pleurisy and acetic acid-induced writhing response in mice is proposed to be dependent on the reduction of eicosanoids mediators formation in the inflammatory site.

Topics: 4,5-Dihydro-1-(3-(trifluoromethyl)phenyl)-1H-pyrazol-3-amine; Analgesia; Animals; Calcimycin; Dinoprostone; Female; Indomethacin; Kinetics; Leukocyte Count; Leukotriene B4; Mice; Neutrophils; Pleurisy; Radioimmunoassay; Xanthenes

The anti-inflammatory effects of Ph CL28A, a potentiator of prostacyclin output and inhibitor of leukotriene (LT) synthesis, were assessed in two models of acute inflammation. In paw oedema induced by carrageenan in rats, Ph CL28A (10-100 mg/kg), given i.p. at the same time as the carrageenan, inhibited oedema for up to 4 h. When indomethacin or Ph CL28A was given locally into the paw with carrageenan, indomethacin inhibited oedema formation but Ph CL28A potentiated the oedema for up to 4 h. As Ph CL28A does not inhibit cyclo-oxygenase, its anti-inflammatory effects in this model may reflect its ability to increase prostacyclin output. In pleurisy induced by carrageenan in rats, there were increases in leukocytes, LTB4, thromboxane B2 (TxB2) and 6-oxo-prostaglandin F1 alpha (6-oxo-PGF1 alpha) in the pleural fluid over 3 h. In this model, Ph CL28A (30 mg/kg) given i.p. decreased leukocyte numbers and LTB4 but did not affect TxB2 or 6-oxo-PGF1 alpha. Indomethacin decreased both prostanoids but did not affect leukocyte accumulation. The beneficial effects of Ph CL28A in two different models of acute inflammation suggests that it may have potential as an anti-inflammatory agent.

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Anti-Inflammatory Agents, Non-Steroidal; Azo Compounds; Blood Pressure; Carrageenan; Edema; Epoprostenol; Hydroxyprostaglandin Dehydrogenases; Indomethacin; Leukotriene B4; Male; Pleurisy; Radioimmunoassay; Rats; Rats, Wistar; Thromboxane B2

A series of pyrazolo[1,5-a]pyrimidin-7-ones (1c-17c) were synthesized to evaluate in vivo and in vitro effects induced by structural modifications at the 2 position of 4,7-dihydro-4-ethyl-2-phenylpyrazolo[1,5-a]pyrimidin-7-one (FPP028). This substance, which has been previously studied, is a weak inhibitor of prostaglandin biosynthesis and a nonacid analgesic and anti-inflammatory agent devoid of ulcerogenic properties. To gain more insight into the mechanism of action of this class of compounds, several in vivo tests were carried out, such as carrageenan-induced rat paw edema and pleurisy. In vitro tests include some studies of leukocyte functions, such as superoxide production and myeloperoxidase release. In vitro effects on arachidonic acid-, adenosine 5'-diphosphate-, and platelet-activating factor-induced platelet aggregation were also studied. Different anti-inflammatory activities were observed, depending on the nature of substituents at the 2 position; these differences are probably linked to the capacity of these compounds to inhibit leukotrienes and/or prostaglandin biosynthesis with different selectivity. 4,7-Dihydro-4-ethyl-2(2-thienyl)pyrazolo[1,5-a]pyrimidin-7-one (7c) proved to be the most interesting compound of the novel synthesized series, showing powerful pharmacological activity in vivo as well as in vitro, together with very weak acute toxicity.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Blood Platelets; Chemotaxis, Leukocyte; Edema; Humans; In Vitro Techniques; Leukotriene B4; Neutrophils; Peroxidase; Platelet Aggregation Inhibitors; Pleurisy; Pyrazoles; Pyrimidines; Rats; Rats, Wistar; Superoxides; Thromboxane B2

The 5-lipoxygenase inhibitors WY-50,295 tromethamine, A-64,077, L-663,536 and ICI-207,968 were compared in a reverse passive Arthus reaction-induced pleurisy model of eicosanoid biosynthesis in the rat. When a 1 h pretreatment schedule was employed, all four inhibitors equivalently blocked leukotriene B4 (LTB4) production with ED50 values of 2.0-2.9 mg/kg p.o. Conversely, WY-50,295 tromethamine (225 mg/kg p.o.) and L-663,536 (100 mg/kg p.o.) did not significantly alter thromboxane B2 (TxB2) levels, whereas A-64,077 (50 mg/kg p.o.) and ICI-207,968 (100 mg/kg p.o.) significantly reduced TxB2 by 50 and 72%, respectively. When 3 and 18 h pretreatment schedules were employed, WY-50,295 tromethamine demonstrated a longer duration of action than the other 5-lipoxygenase inhibitors with ED50 values of 1.7 and 6.3 mg/kg p.o., respectively. At doses of 50 and 100 mg/kg p.o., all drugs tested significantly inhibited inflammatory cell influx by 15-27%, albeit in a non-dose-related manner. However, only A-64,077 significantly lowered fluid extravasation by 35%, presumably due to inhibition of cyclooxygenase product formation. These results demonstrate that in this rat reverse passive Arthus pleurisy model, WY-50,295 tromethamine potently and selectively inhibits 5-lipoxygenase in vivo, and possesses a longer duration of action than the other 5-lipoxygenase inhibitors employed.

Topics: Animals; Arthus Reaction; Biomarkers; Dose-Response Relationship, Drug; Eicosanoids; Exudates and Transudates; Inflammation; Leukotriene B4; Lipoxygenase Inhibitors; Male; Pleurisy; Radioimmunoassay; Rats

1. The effect of disulfiram and A-64077 on leukotriene B4 biosynthesis was investigated using human polymorphonuclear leukocyte preparations and an in vivo rat pleurisy assay. 2. Disulfiram inhibited the calcium ionophore-induced release of LTB4 by human leukocytes in vitro with an IC50 of 4.6 +/- 0.3 microM, a value similar to that observed with the 5-lipoxygenase inhibitor A-64077 (IC50 = 1.2 +/- 0.3 microM). These inhibitors were at least 100-fold more potent than diethyldithiocarbamate, the primary metabolite of disulfiram. 3. In a rat pleurisy model, the administration of A-64077 (p.o., 2 hr pretreatment) caused a marked decrease in LTB4 levels measureable after ionophore stimulation at doses of 3 and 10 mg kg (67 and 96% inhibition, respectively). Disulfiram was about a 100-fold less potent, inhibiting LTB4 release by 65% at 300 mg kg (p.o., 6 hr pretreatment). 4. In contrast to A-64077, the inhibitory effect of disulfiram on LTB4 production by isolated leukocytes from the pleural cavity was reduced by the addition of the cell-free pleural exudate, suggesting that protein binding or conversion of disulfiram to inactive species contributes to diminish the potency of the drug. 5. The results indicate that disulfiram, after oral administration in rats, causes an inhibition of leukotriene biosynthesis in the pleural cavity and further illustrate the limited specificity of this drug as an inhibitor of aldehyde dehydrogenase at doses generally used to inhibit this enzyme in vivo.

Topics: Aldehyde Dehydrogenase; Animals; Carrageenan; Colitis, Ulcerative; Disulfiram; Exudates and Transudates; Humans; Hydroxyurea; In Vitro Techniques; Leukocytes; Leukotriene B4; Lipoxygenase Inhibitors; Male; Pleurisy; Rats; Rats, Inbred Strains

CGS 22745, and aralkyl hydroxamic acid, inhibited 5-hydroxyeicosatetraenoic acid (5-HETE) and leukotriene B4 (LTB4) synthesis in guinea pig leukocytes (IC50 = 0.6 microM). The compound did not appreciably affect cyclooxygenase (ram seminal vesicles), 12-lipoxygenase and thromboxane synthase (human platelets) or 15-lipoxygenase (human neutrophils). CGS 22745 inhibited A23187-induced formation of LTB4 in blood (IC50's of 4.3, 0.56 and 3.2 microM for human, dog and rat, respectively). At 1 mg/kg i.v. in dogs, it caused 96% inhibition of A23187-stimulated LTB4 formation ex vivo after 5 min. Its effective biological half-life was greater than 160 min. In dogs at 3 and 10 mg/kg p.o., CGS 22745 inhibited ex vivo A23187-stimulated LTB4 formation at 3 hr by 48% and 97%, respectively. The inhibition persisted up to 6 hr (26% at 3 mg/kg; 49% at 10 mg/kg). CGS 22745 (3, 10 and 30 mg/kg p.o.) inhibited exudate formation, mononuclear cells and PMN accumulation in a dose-dependent manner during the late phase (48 and 72 hr) of carrageenan-induced pleurisy in the rat.

Topics: Administration, Oral; Animals; Anti-Inflammatory Agents, Non-Steroidal; Arachidonic Acid; Biological Availability; Blood Platelets; Calcimycin; Dogs; Guinea Pigs; Half-Life; Humans; Hydroxamic Acids; In Vitro Techniques; Leukocytes; Leukotriene B4; Lipoxygenase Inhibitors; Neutrophils; Pleurisy; Pyrroles; Rats; Sheep

We have compared the early development (0-4h) of two acute non-specific inflammatory reactions induced by the intrapleural injection of isologous serum or a suspension of CaPP crystals. The intensity of the reactions was assessed in terms of the exudate volume, the number and ratio of pleural cells and different cell functions and secretions. The number of exudative cells elicited by isologous serum was higher than with CaPP but the PMN/Monocytes ratio was the same. The amount of protein in the serum-induced exudate was constant from 1 h to 4 h and was similar in the CaPP-induced pleural exudate at the latter time. The amount of complement increased similarly in the two models. The chemotactic potency of the exudates and cell supernatants following incubation showed similar values in the two models. Eicosanoid levels were higher in CaPP--than in isologous serum-induced exudates. Prostacyclin and peptidoleukotrienes were released in specially large amounts at the very outset of the inflammatory reactions.

Topics: Acute Disease; Animals; Calcium Phosphates; Cells, Cultured; Eicosanoids; Epoprostenol; Leukocytes, Mononuclear; Leukotriene B4; Male; N-Formylmethionine Leucyl-Phenylalanine; Pleurisy; Rats; Rats, Inbred Strains; SRS-A; Thromboxane B2

The first phase of the healing process is characterized by the development of an inflammatory reaction involving migration of inflammatory cells and release of inflammatory mediators. In a previous study, we have demonstrated that the water soluble tetrachlorodecaoxygen complex (TCDO), first synthetized to promote wound healing, inhibits polymorphonuclear (PMN) migration. The aim of the present study was to investigate the activity of TCDO on the progression of an acute non-specific inflammatory reaction, on the release of 6-keto-PGF1 alpha and PGE2 and on PMN oxidative metabolism in the rat. Injected in the pleural cavity, TCDO (15 mumoles/rat) significantly decreased the number of exudative cells while 1.5 mumoles/rat inhibited PMN oxidative metabolism ex vivo (assessed by chemiluminescent assay and measurement of O2- generation) after stimulation of the cells by opsonized zymosan. Similar observations were made in vitro after incubation of PMNs with various concentrations of TCDO (300 to 3 microM). The effect was dose-related and highly significant up to the concentration of 3 microM. In parallel, TCDO decreased the amounts of 6-keto-PGF1 alpha and PGE2 in exudates harvested 1 hour after the intrapleural injection of isologous serum. Effects were significantly different from control levels, from 1.5 to 0.03 mumoles/rat for 6-keto-PGF1 alpha and from 1.5 to 0.01 mumoles/rat for PGE2. This effect was observed when TCDO was injected at the same time or 1 hour before the isologous serum but not later. TCDO also inhibited LTB4 generation in vitro after PMN stimulation by calcium ionophore A23187, at concentrations up to 150 microM. The effects of TCDO in vivo and in vitro on rat PMN functions and inflammatory mediator release mimic certain activities of anti-inflammatory drugs. These properties may be beneficial in the very early stages of the wound healing process.

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Anti-Inflammatory Agents, Non-Steroidal; Calcimycin; Chlorine; Dinoprostone; Leukotriene B4; Luminescent Measurements; Male; Neutrophils; Oxidation-Reduction; Oxides; Pleura; Pleurisy; Rats; Rats, Inbred Strains; Superoxides; Wound Healing

Previous studies have shown that leukotriene B4 is metabolized by polymorphonuclear leukocytes (PMNL) by a 20-hydroxylase, a 19-hydroxylase, and a reductase. We have now identified for the first time LTB4 metabolites formed by a combination of the reductase and omega-oxidation pathways. We have also discovered that rat PMNL metabolize LTB4 by a novel pathway to 18-hydroxy products. Dihydro metabolites of LTB4 have formerly been reported only after incubation of exogenous LTB4 with PMNL, but we have now shown that they are formed to the same extent from endogenous arachidonic acid after stimulation of PMNL with the ionophore, A23187. The following metabolites have been identified after incubation of either LTB4 or arachidonic acid with rat PMNL: 10,11-dihydro-LTB4, 10,11-dihydro-12-epi-LTB4, 10,11-dihydro-12-oxo-LTB4, 19-hydroxy-LTB4, 19-hydroxy-10,11-dihydro-LTB4, 19-oxo-10,11-dihydro-LTB4, 18-hydroxy-LTB4, 18-hydroxy-10,11-dihydro-LTB4, and 18-hydroxy-10,11-dihydro-12-oxo-LTB4. Negligible amounts of 20-hydroxylated products were formed. Incubation of PMNL with 10,11-dihydro-LTB4 resulted in the formation of all of the above dihydro metabolites. However, none of the omega-oxidized metabolites of LTB4 was further metabolized to a significant extent when incubated with PMNL, possibly at least partially because they were not substrates for a specific LTB4 uptake mechanism. We found that the biosynthesis and metabolism of LTB4 is considerably enhanced in PMNL from an inflammatory site (carrageenan-induced pleurisy) compared with peripheral PMNL. When arachidonic acid was the substrate, the greatest increase was observed for products formed by the reductase pathway, which were about eight times higher in pleural PMNL. The rates of formation of both LTA hydrolase and omega-hydroxylase products were about three times higher, whereas the total amounts of 5-lipoxygenase products were about twice as high in pleural PMNL. The amounts of products formed by the above enzymatic pathways reached maximal levels about 4-6 h after injection of carrageenan and then declined.

Topics: Animals; Arachidonate 5-Lipoxygenase; Arachidonic Acid; Arachidonic Acids; Calcimycin; Carrageenan; Chromatography, High Pressure Liquid; Cytochrome P-450 Enzyme System; Cytochrome P450 Family 4; Epoxide Hydrolases; Hydroxylation; Leukotriene B4; Male; Mass Spectrometry; Mixed Function Oxygenases; Neutrophils; Oxidation-Reduction; Oxidoreductases; Pleurisy; Rats; Rats, Inbred Strains

Acute non-specific inflammation was induced in rats by injection of isologous serum into the pleural cavity. Pleural and peritoneal cells were collected at various times after pleurisy induction and tested for production of leukotriene B4 (LTB4), prostaglandin E2 (PGE2) and prostacyclin (PGI2) after in-vitro stimulation with calcium ionophore A23187. Cells obtained by lavage of pleural and peritoneal cavities of normal rats were used as controls. Increased production of LTB4, PGE2 and PGI2 by pleural cells was observed 3 days after pleurisy induction, but with a significant depression of PGI2 release at 3 h. As the relative proportions of polymorphonuclear cells (PMN) and macrophages in the inflammatory exudate varied during the development of inflammation, these cells were examined separately for LTB4 production. PMN and macrophages contributed equally to the liberation of this mediator in normal and inflamed rats. Similar qualitative and quantitative changes in LTB4 production by pleural cells were observed, irrespective of the type of irritant used (isologous serum, dextran, carrageenan, microcrystals). In contrast, intrapleural injection of saline had no significant effect. In order to determine whether local inflammation may influence mediator release by phagocytic cells at remote sites, peritoneal cells were collected 3 or 72 after pleurisy induction. The production of LTB4, PGE2 and PGI2 was increased at 72 h. Mediator production by peritoneal macrophages was observed in both normal and inflamed rats. In conclusion, acute non-specific inflammation provoked increased arachidonic acid metabolite generation by phagocytes both locally and at a distance: this occurred more than 24 h after pleurisy resolution.

Topics: 6-Ketoprostaglandin F1 alpha; Acute Disease; Animals; Cells, Cultured; Dinoprostone; Eicosanoids; Epoprostenol; Leukotriene B4; Macrophages; Male; Neutrophils; Pleurisy; Rats; Rats, Inbred Strains; Tuftsin

A single injection of a streptococcal preparation, OK-432, with fresh frozen plasma (FFP) (or fresh human serum) into the peritoneal or pleural cavity for the treatment of malignant ascites or pleurisy resulted in a complete reduction of ascitic fluid or pleural effusion in 5 out of 11 patients. FFP was used a further source of complement for the effective accumulation of antitumor polymorphonuclear leukocytes (PMNs) by complement-derived chemotactic factors in the cavity. C5a increased in the fluids 3-9 h after the injection and preceded a massive increase in PMNs. C1 inhibitor (C1INH) and C3b inactivator (C3bINA) decreased in several cases 6 h after the treatment. Chemotactic arachidonic acid metabolites, thromboxane B2(TXB2) as a characteristics of TXA2, and leukotriene B4(LTB4) also increased at the same time even in cases where C5a changed only minimally, and may play a role in accumulating antitumor PMNs in the cavity.

Topics: Adult; Aged; Aged, 80 and over; Ascites; Biological Products; Complement Activation; Complement C5; Complement C5a; Female; Freezing; Humans; Immunization, Passive; Leukotriene B4; Male; Middle Aged; Neoplasms; Neutrophils; Picibanil; Pleurisy; Thromboxane B2

Topics: Animals; Arachidonate 5-Lipoxygenase; Arachidonic Acid; Arachidonic Acids; Cell Count; Cyclooxygenase Inhibitors; Eicosanoids; Hydroxyeicosatetraenoic Acids; L-Lactate Dehydrogenase; Leukotriene B4; Lipoxygenase Inhibitors; Macrophages; Male; Neutrophils; Pleura; Pleurisy; Prostaglandin-Endoperoxide Synthases; Rats; Rats, Inbred Strains

CGS 8515 inhibited 5-hydroxyeicosatetraenoic acid (5-HETE) and leukotriene B4 synthesis in guinea pig leukocytes (IC50 = 0.1 microM). The compound did not appreciably affect cyclooxygenase (sheep seminal vesicles), 12-lipoxygenase (human platelets), 15-lipoxygenase (human leukocytes) and thromboxane synthetase (human platelets) at concentrations up to 100 microM. CGS 8515 inhibited A23187-induced formation of leukotriene products in whole blood (IC50 values of 0.8 and 4 microM, respectively, for human and rat) and in isolated rat lung (IC50 less than 1 microM) in vitro. The selectivity of the compound as a 5-lipoxygenase inhibitor was confirmed in rat whole blood by the 20-70-fold separation of inhibitory effects on the formation of leukotriene from prostaglandin products. Ex vivo and in vivo studies with rats showed that CGS 8515, at an oral dose of 2-50 mg/kg, significantly inhibited A23187-induced production of leukotrienes in whole blood and in the lung. The effect persisted for at least 6 h in the ex vivo whole blood model. CGS 8515, at oral doses as low as 5 mg/kg, significantly suppressed exudate volume and leukocyte migration in the carrageenan-induced pleurisy and sponge models in the rat. Inhibitory effects of the compound on inflammatory responses and leukotriene production in leukocytes and target organs are important parameters suggestive of its therapeutic potential in asthma, psoriasis and inflammatory conditions.

Topics: Animals; Arachidonate Lipoxygenases; Arachidonic Acid; Arachidonic Acids; Benzoquinones; Biotransformation; Blood Platelets; Calcimycin; Dexamethasone; Guinea Pigs; Humans; Hydroxyeicosatetraenoic Acids; Indomethacin; Leukocytes; Leukotriene B4; Lipoxygenase Inhibitors; Male; Naphthoquinones; ortho-Aminobenzoates; Pleurisy; Quinones; Rats; Rats, Inbred Strains; Sheep

Immunoreactive leukotriene B4 (iLTB4), detected in the pleural cavity following induction of a reverse passive Arthus reaction (RPAR), was inhibited by the mixed lipoxygenase-cyclooxygenase inhibitors, phenidone and BW 755C, but not by cyclooxygenase inhibitors or by chlorpheniramine or methysergide. Both iLTB4 production and the subsequent pleural inflammation were dependent upon the dose of BSA antigen employed to elicit the RPAR pleurisy. However, inasmuch as BW 755C and phenidone were not distinguished from the cyclooxygenase inhibitors in their effects on fluid accumulation and cellular infiltration in RPAR pleurisy, it is doubtful that LTB4 plays a functional role in this inflammation model.

Topics: Animals; Antigens; Arthus Reaction; Leukotriene B4; Male; Pleurisy; Rats; Rats, Inbred Lew; Serum Albumin, Bovine

Arachidonic acid-induced pleurisy in the rat was evaluated for testing inhibitors of arachidonic acid (AA) metabolism. The model involves the administration of AA intrapleurally and the determination of LTB4 and PGE2 as indicators of 5-lipoxygenase and cyclooxygenase activities in the exudate/wash. This model is suitable for the in vivo evaluation of potential inhibitors of the 5-lipoxygenase pathway but not the cyclooxygenase pathway of AA cascade.

Topics: 4,5-Dihydro-1-(3-(trifluoromethyl)phenyl)-1H-pyrazol-3-amine; Animals; Arachidonate Lipoxygenases; Arachidonic Acids; Cyclooxygenase Inhibitors; Dinoprostone; Disease Models, Animal; Indomethacin; Leukotriene B4; Lipoxygenase Inhibitors; Male; Pleurisy; Prostaglandins E; Pyrazoles; Rats; Rats, Inbred Strains; Time Factors

The metabolism of leukotrienes (LTs) in the cell-containing inflammatory exudate of rat pleurisy was studied in vitro. The exudates of both nonallergic carrageenin-induced pleurisy and IgG immune complex-mediated pleurisy converted 3H-LTB4 to 20-OH LTB4, but virtually did not metabolized 3H-LTC4 or 3H-LTE4 up to 2 hrs. 3H-LTD4 was changed to LTC4 by the exudate of non-allergic pleurisy, whereas 3H-LTD4 was metabolized to LTE4 by that of allergic pleurisy. Reflecting on the different metabolism, the gamma-glutamyl transpeptidase activity in the exudate of carrageenin-induced pleurisy was significantly higher than that in IgG immune complex mediated pleurisy. The enzyme activity was not derived from the blood itself, but from the infiltrated polymorphonuclear leukocytes. The activity of the cell homogenate in both exudates was not significantly different. Thus, it could be concluded that the difference in the metabolism of LTD4 between the nonallergic and allergic pleural exudates in vitro was mainly attributable to the enhanced activity of the gamma-glutamyl transpeptidase released in the exudate.

Topics: Animals; Antigen-Antibody Complex; Carrageenan; gamma-Glutamyltransferase; Immunoglobulin G; In Vitro Techniques; Inflammation; Kinetics; Leukotriene B4; Male; Pleurisy; Rats; Rats, Inbred Strains; SRS-A

In studies of the role of leukotrienes in inflammatory reactions, the induction of rat reversed passive Arthus pleurisy (a type III allergic reaction) was employed. Increases of exudate volume, vascular permeability, and migration of inflammatory cells in the pleural cavity were observed. The vascular permeability was enhanced biphasically during 0-30 min (early response) and during 3-6 h (late response) after induction of the pleurisy. The infiltration of inflammatory cells, mainly polymorphonuclear leukocytes, into the cavity increased and reached a maximum 6 h after the pleurisy was induced. Leukotriene B4 (LTB4), 5-monohydroxyeicosatetraenoic acid (5-HETE), and slow-reacting substance of anaphylaxis (SRS-A), consisting of LTC4, LTD4 and LTE4, were detected in the exudate by reversed-phase high-performance liquid chromatography during the early response. The contents of LTC4 reached a maximum 10 min after the challenge, followed by a rapid decrease within 1 h. The rise and decay of LTC4 correlated with the increase in vascular permeability during the early phase. AA-861, a 5-lipoxygenase inhibitor, given intrapleurally inhibited the increase in vascular permeability, cell migration, and generation of leukotrienes during the early phase of the pleurisy. These results indicate that products of the 5-lipoxygenase pathway, such as LTC4 and LTB4, may play an important role as chemical mediators in the inflammatory reaction.

Topics: Animals; Arachidonate Lipoxygenases; Arthus Reaction; Benzoquinones; Biological Assay; Capillary Permeability; Chemotaxis, Leukocyte; Eosinophils; Female; Hydroxyeicosatetraenoic Acids; Leukotriene B4; Lipoxygenase Inhibitors; Male; Mice; Monocytes; Neutrophils; Pleurisy; Pyrilamine; Quinones; Rabbits; Rats; SRS-A

Carrageenin pleurisy was induced in adrenalectomised (ADX) and sham-operated (SHO) rats. The magnitude and duration of inflammation, as estimated by fluid exudation and cell migration, was greatly increased (approximately doubled) in ADX rats compared with that in their SHO controls. The content of eicosanoids (6-keto-prostaglandin F1 alpha (6-keto-PGF 1 alpha), thromboxane B2 (TXB2), and leukotriene B4 (LTB4] in inflammatory exudates from ADX rats was significantly (2-4 fold) greater than that of their SHO controls. Resident macrophages obtained from ADX rats produced more eicosanoids per cell per unit time when stimulated in vitro with zymosan, than did cells from the SHO controls. Administration of glucocorticoids blocked the inflammatory response and reduced the release of eicosanoids both in vitro and in vivo in both groups of rats. These data are consistent with the notion that physiological amounts of glucocorticoids exert a tonic inhibitory action on phospholipase activity in normal animals and that the increased secretion of these hormones during the inflammatory response serves to check and control the development of inflammation.

Topics: 6-Ketoprostaglandin F1 alpha; Acute Disease; Adrenalectomy; Animals; Annexins; Carrageenan; Glucocorticoids; Glycoproteins; In Vitro Techniques; Inflammation; Leukotriene B4; Phospholipases A; Pleurisy; Rats; Thromboxane B2

Rat IgE pleurisy was induced by the injection of di-nitrophenol-conjugated bovine serum albumin (DNP-BSA) 48 hours after the intrapleural injection of rat anti-DNP-IgE serum. IgG-BSA complex pleurisy was also induced by the intrapleural injection of IgG-BSA complexes produced at the optimum ratio in vitro. Plasma exudation was markedly increased in the first 20 minutes, but not observed thereafter, in IgE pleurisy, whereas marked plasma exudation in the first 20 minutes was followed by weak exudation at three and five hours in IgG-BSA complex pleurisy. Leukotrienes (LTs) E4 (100 ng/rat), D4 (32) and B4 (16) were detected on HPLC in the pleural exudate in the first 20 minutes of IgG-BSA complex pleurisy, but less (9 ng/rat) LTE4 alone was detected in the five-hour exudate. The first 20-minute pleural exudate contained 13 ng/rat of LTE4 in IgE pleurisy. The plasma was completely inhibited by simultaneous treatment of rats with pyrilamine (2.5 mg/kg, i.p.) and methysergide (3 mg/kg, i.p.), as it was in compound 48/80-induced pleurisy. In IgG-BSA complex pleurisy, 90% of the pleural exudate for the first 20 minutes was inhibited by the same treatment, and the rest was completely suppressed by simultaneous treatment with an intrapleural injection of AA-1777, a selective 5-lipoxygenase inhibitor. AA-1777 alone did not reduce the plasma exudation significantly. The 5-lipoxygenase inhibitor was also very effective in reducing the migrating numbers of polymorphonuclear and mononuclear leukocytes to half, without affecting the eosinophils of mast cells.

Topics: Animals; Antigen-Antibody Complex; Benzoquinones; Chemotaxis, Leukocyte; Chromatography, High Pressure Liquid; Disease Models, Animal; Exudates and Transudates; Immunoglobulin E; Immunoglobulin G; Leukotriene B4; Leukotriene E4; Lipoxygenase Inhibitors; Methysergide; Pleurisy; Pyrilamine; Quinones; Rats; Rats, Inbred Strains; Receptors, Histamine; Receptors, Serotonin; Respiratory Hypersensitivity; SRS-A

Leukotriene B4 (LTB4) has been implicated as a mediator in the inflammatory process by virtue of its potent chemotactic activity. At present, very little is known of the stability of this compound in vivo; therefore, the present study was designed to determine the half-life and metabolic fate of radiolabeled LTB4 during a 2-hr intrapleural incubation in rats with acute carrageenan pleurisy. After injection of 0.2 ml of 1% sodium carrageenan (Viscarin), inflammation was allowed to develop for 4 hr. A small polyethylene cannula was then inserted into the chest, and 0.1 microCi of [14C]LTB4 was injected into the chest. Samples for radioactivity determination were taken at 0, 1, 2, 3, 4, 5, 7, 10, 15, 20, 30, 45, 60, 90 and 120 min via the cannula, and at 120 min the entire content of the chest was collected. The half-life for the disappearance of radioactivity from the chest was 45.8 +/- 3.5 min. The 120-min samples were treated with acetone to precipitate protein and extracted with Sep-Paks. The extracts were analyzed by reversed phase high performance liquid chromatography using an ultraviolet detector set at 269 nm and a radioactivity detector. An additional experiment was run using multi-[3H]LTB4, and the only major metabolites detected were omega-hydroxylated compounds. It can be concluded from these results that LTB4 is relatively stable in vivo and could be present for long enough at the inflammatory site to have an influence upon inflammatory cell migration.

Topics: Animals; Carrageenan; Cell Movement; Chromatography, High Pressure Liquid; Female; Half-Life; Kinetics; Leukotriene B4; Pleural Effusion; Pleurisy; Rats

AA-861, a selective 5-lipoxygenase inhibitor, suppressed A23187-induced formations of 5-HETE and LTB4 in rat peritoneal macrophages. Immunologically-stimulated generation of SRS-A was also inhibited in guinea pig lung and rat peritoneal cavity. AA-861 had no effects on histamine release from rat mast cells or passive cutaneous anaphylaxis in rats. Essentially no antagonistic activity to LTD4 or histamine was observed. This compound exerted an obvious inhibition of allergic bronchoconstriction in guinea pigs and a moderate reduction of carrageenin-induced paw edema and pleurisy in rats. These findings suggest that SRS-A plays an important role in asthmatic and inflammatory reactions.

Topics: Animals; Arachidonate Lipoxygenases; Asthma; Benzoquinones; Edema; Female; Guinea Pigs; Histamine Release; Hydroxyeicosatetraenoic Acids; Leukotriene B4; Lipoxygenase Inhibitors; Lung; Macrophages; Male; Mast Cells; Passive Cutaneous Anaphylaxis; Pleurisy; Quinones; Rats; Rats, Inbred Strains; SRS-A