calcimycin and Pleurisy

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

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

Intrapleural injection of zymosan into rats induces acute inflammation characterized by plasma leakage and cellular influx. The level of type II phospholipase A2 (PLA2) increased in the pleural fluid as well as in exudating leukocytes after the injection of zymosan. Rather low PLA2 activity was found in cell lysates, though treatment of such lysates at low pH increased the PLA2 activity drastically. The appearance of "acid-extracted" PLA2 activity in leukocytes preceded that of the extracellular enzyme activity, suggesting that pleural leukocytes might be one of the origins of the extracellular enzyme. Treatment of exudating pleural leukocytes with purified rat type II PLA2 elicited the production of prostaglandin E2, but not platelet-activating factor appreciably. These findings indicate that type II PLA2 might play a role in the progression of inflammation through the production of eicosanoids in the present inflammation model.

Topics: Animals; Calcimycin; Dinoprostone; Kinetics; Leukocyte Count; Leukocytes; Male; Neutrophils; Phospholipases A; Phospholipases A2; Pleural Effusion; Pleurisy; Rats; Rats, Sprague-Dawley; Zymosan

Intrapleural injection of A-23187 (10 micrograms), a calcium ionophore, elicited rapid increase in biosynthesis of prostaglandins and leukotrienes in a time-dependent manner. 6-Keto-prostaglandin-F1 alpha (6-KPA) was the principal cyclooxygenase product with modest increases in levels of thromboxane B2 and prostaglandin-E2. Orally administered indomethacin, a selective cyclooxygenase inhibitor, and three selective 5-lipoxygenase inhibitors, zileuton, A-78773 and ICI-D-2138 markedly attenuated respective arachidonate pathways with projected ED50 values of < 1-2 mg/kg. Furthermore, a single oral administration of either ICI-D-2138 or A-78773 (each 20 mg/kg, po) resulted in persistent inhibition of 5-lipoxygenase pathway for up to 24 hr. These results indicate zileuton, A-78773 and ICI-D-2138 to be potent and selective inhibitors of 5-LO and document the utility of A-23187-induced pleural inflammation in evaluating efficacy of inhibitors of arachidonic acid metabolism in vivo.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Calcimycin; Disease Models, Animal; Drug Evaluation, Preclinical; Eicosanoids; Hydroxyurea; Leukotrienes; Lipoxygenase Inhibitors; Male; Pleurisy; Prostaglandins; Pyrans; Quinolones; Rats; Rats, Sprague-Dawley

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

Intrapleural injection of the ionophore A23187 in rats induced leukotriene (LT) production, prostaglandin E2 production, plasma exudation and leukocyte accumulation in the pleural cavity. We evaluated the inhibitory effects of orally administered drugs on 5-lipoxygenase activity by their ability to reduce the content of both peptido-LTs (LTC4, LTD4 and LTE4) and LTB4 in this model. TZI-41127, a novel selective 5-lipoxygenase inhibitor, significantly reduced the peptido-LTs and LTB4 content with ED50 values of 4.2 and 6.1 mg/kg, respectively, whereas it only reduced the prostaglandin E2 content (cyclooxygenase activity) by 31.1% even after 100 mg/kg. Phenidone inhibited 5-lipoxygenase activity more selectively than cyclooxygenase activity. BW755C inhibited cyclooxygenase activity more selectively than 5-lipoxygenase activity. Indomethacin selectively inhibited cyclooxygenase activity. These results suggest that: (1) A23187-induced pleurisy is an convenient in vivo model for studying drug effects on 5-lipoxygenase and cyclooxygenase activities and (2) TZI-41127 is an orally active and comparatively selective inhibitor of 5-lipoxygenase activity.

Topics: 4,5-Dihydro-1-(3-(trifluoromethyl)phenyl)-1H-pyrazol-3-amine; Animals; Calcimycin; Chromatography, High Pressure Liquid; Cyclooxygenase Inhibitors; Dinoprostone; Indoles; Leukocytes; Leukotrienes; Lipoxygenase Inhibitors; Male; Pleura; Pleurisy; Radioimmunoassay; Rats; Rats, Inbred Strains

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

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