thromboxane-b2 and methyl-2-((3-4-dihydro-3-4-dioxo-1-naphthalenyl)amino)benzoate

Interleukin-6 (IL-6) is a cytokine involved in the terminal differentiation of B-cells, T-cell activation, and secretion of hepatic acute phase proteins. The production of IL-6 is regulated by many factors, including IL-1 and lipopolysaccharide (LPS). Because IL-6 may be an important contributor to the effects of LPS in inflammation and septic shock, we investigated the ability of LPS to induce IL-6 release from peritoneal macrophages (m phi) in vitro. M phi were isolated from male Long-Evans rats, and cultured in 96-well tissue culture plates at 1 x 10(5) cells/well in serum-free RPMI-1640 medium. Following a 2-hr attachment period, the cells were rinsed twice to remove the nonadherent cells. LPS (0.006-100 ng/ml) stimulated IL-6 release by six- to 12-fold during a 4 hr incubation. In contrast, IL-1 beta (0.006-100 ng/ml) had no effect. Because cyclooxygenase metabolites of arachidonic acid are increased by LPS, we determined the effects of indomethacin (a cyclooxygenase inhibitor) and CGS8515 (a 5-lipoxygenase inhibitor) on LPS-induced IL-6 release. Neither indomethacin (10 microM) nor CGS8515 (2.5 microM) had any effect on basal or LPS-induced IL-6 release. Very low concentrations of LPS (0.01-1,000 pg/ml) stimulated IL-6 by two- to threefold. Pertussis toxin (10 ng/ml), which inactivates Gi protein, had no effect on LPS-induced IL-6 release from mø. Thromboxane B2 (TXB2) concentrations were also elevated with as little as 0.1 pg/ml LPS; however, pertussis toxin inhibited LPS-stimulated TXB2 release.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Antigens, CD; Antigens, Differentiation, Myelomonocytic; In Vitro Techniques; Indomethacin; Interleukin-1; Interleukin-6; Lipopolysaccharide Receptors; Lipopolysaccharides; Macrophages, Peritoneal; Male; Naphthoquinones; ortho-Aminobenzoates; Pertussis Toxin; Rats; Signal Transduction; Thromboxane B2; Virulence Factors, Bordetella

We evaluated the effect of tumor necrosis factor-alpha (TNF-alpha) and interleukin-1 alpha (IL-1 alpha) on pig cardiopulmonary function by intravenously infusing each cytokine individually or in combination (0.5 microgram/kg from 0 to 0.5 h + 5 ng.kg-1 x min-1 from 0.5 to 6 h for each cytokine). The role of eicosanoids in mediating the TNF-alpha + IL-1 alpha-induced cardiopulmonary dysfunction was also investigated by pretreating cytokine-infused pigs with CGS 8515 (5-lipoxygenase inhibitor) or indomethacin (cyclooxygenase inhibitor). Coinfusion of TNF-alpha with IL-1 alpha caused additive increases (P < 0.05) in total peripheral resistance and plasma concentrations of 6-keto-prostaglandin F1 alpha (PGF1 alpha). The increases in mean pulmonary arterial pressure (Ppa), pulmonary vascular resistance (PVR), alveolar-arterial O2 gradient (AaDO2), alveolar dead space-to-tidal volume ratio (VD/VT), and plasma concentrations of thromboxane B2 were either additive or synergistic. CGS 8515 blocked the TNF-alpha + IL-1 alpha-induced increases (P < 0.05) in mean aortic pressure, total peripheral resistance (4-6 h), VD/VT (5-6 h), and, at 6 h, attenuated the increases in Ppa, PVR, and AaDO2. Indomethacin blocked or attenuated the cytokine-induced increases (P < 0.05) in Ppa, PVR, AaDO2, VD/VT, and plasma concentrations of thromboxane B2 and 6-keto-PGF1 alpha. The 1-to 2-h systemic hypotension, caused by TNF-alpha + IL-1 alpha, was not abrogated by either indomethacin or CGS 8515. The cytokines did not alter plasma concentrations of leukotriene B4 or 5-hydroxyeicosatetraenoic acid. We conclude that coinfusion of TNF-alpha with IL-1 alpha induces physiological responses that are additive or synergistic and that cyclooxygenase and 5-lipoxygenase products (other than leukotriene B4 and 5-hydroxyeicosatetraenoic acid) importantly mediate cardiopulmonary dysfunction in pigs infused with TNF-alpha + IL-1 alpha.

Topics: 6-Ketoprostaglandin F1 alpha; Albumins; Animals; Arachidonic Acids; Bronchoalveolar Lavage Fluid; Chromatography, High Pressure Liquid; Cyclooxygenase Inhibitors; Cytokines; Dinoprost; Drug Synergism; Eicosanoids; Heart; Heart Diseases; Hydroxyeicosatetraenoic Acids; Indomethacin; Injections, Intravenous; Interleukin-1; Leukotriene B4; Lipoxygenase Inhibitors; Lung; Lung Diseases; Naphthoquinones; ortho-Aminobenzoates; Swine; Thromboxane B2; Tumor Necrosis Factor-alpha; Vascular Resistance

We hypothesized that 5-lipoxygenase and cyclooxygenase products might be mediators of cardiopulmonary and systemic vascular effects induced by a 4 h continuous infusion of platelet-activating factor (PAF, 10 ng/kg/min) in anesthetized pigs. Indomethacin (cyclooxygenase inhibitor) potentiated and CGS 8515 (5-lipoxygenase inhibitor) attenuated PAF-induced increases in total peripheral resistance (TPR) from 2.5 to 4 h. However, the 5-lipoxygenase inhibitor failed to modify pulmonary vasoconstriction and hypertension caused by PAF. Except for a delay in onset (approximately 44 s) and rate of development of pulmonary hypertension during the initial 10 min of PAF infusion, the pulmonary hemodynamic changes were also not attenuated by indomethacin. On the other hand, at 4 h, the PAF-induced pulmonary hypertension and systemic vasoconstriction were completely or partially reversed, respectively, by WEB 2086 (PAF receptor antagonist). The PAF-induced increases in plasma thromboxane B2 (TXB2) were blocked by indomethacin but not by CGS 8515, and at 4 h the 5-lipoxygenase inhibitor potentiated the levels of TXB2 in pigs treated with PAF. The plasma concentrations of 6-keto-PGF1 alpha and leukotriene B4 (LTB4) were not modified by PAF or CGS 8515 + PAF. We conclude that PAF-induced increases in TPR (2.5-4 h) are potentiated by indomethacin and are dependent on 5-lipoxygenase products other than LTB4. Although the early pulmonary vascular response (< 10 min) to PAF is dependent on cyclooxygenase products, the sustained response (after 10 min) cannot be explained by either 5-lipoxygenase or cyclooxygenase products but may be mediated directly by PAF receptors.

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Azepines; Blood; Calcimycin; Chromatography, High Pressure Liquid; Cyclooxygenase Inhibitors; Hemodynamics; Hypertension, Pulmonary; In Vitro Techniques; Indomethacin; Infusions, Intra-Arterial; Leukotriene B4; Lipoxygenase Inhibitors; Naphthoquinones; ortho-Aminobenzoates; Platelet Activating Factor; Swine; Thromboxane B2; Triazoles

The effects of a highly selective 5-lipoxygenase inhibitor, CGS8515 [methyl 2-[(3,4-dihydro-3,4-dioxo-1-naphthalenyl) amino]benzoate], on endotoxic shock sequelae and eicosanoid synthesis by peritoneal macrophages were evaluated in the rat. Pretreatment of peritoneal macrophages in vitro with CGS8515 significantly inhibited the synthesis (P less than .01) of immunoreactive leukotriene C4/leukotriene D4 stimulated by the calcium ionophore (A23187). Inhibition of 5-lipoxygenase produced significant shunting to immunoreactive thromboxane B2 formation (P less than .05). In rats sedated with ketamine.HCl (82.5 mg/kg) and xylazine. HCl (27.5 mg/kg), i.v. injection of Salmonella enteritidis endotoxin (25 mg/kg i.v.) produced significant decreases at 30 min in mean arterial pressure (from 89 +/- 4 to 44 +/- 8 mm Hg, N = 5, P less than .001); in white blood cell count (from 10.8 +/- 0.6 to 6.5 +/- 0.8 x 10(3)/mm3, N = 5, P less than .01); in platelet count (from 687 +/- 66 to 392 +/- 65 x 10(3)/mm3, N = 5, P less than .01); and produced an increase of hematocrit (from 46 +/- 1.2 to 57.4 +/- 1.8%, N = 5, P less than .03). CGS8515 (5 mg/kg i.v. 30 min before endotoxin injection, N = 6) blunted the endotoxin-induced hypotension by 35% (P less than .001), the leukopenia by 24% (P less than .03), the thrombocytopenia by 45% (P less than .006) and the hemoconcentration by 16% (P less than .03), compared to the shocked control rats 30 min after endotoxin injection.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Arachidonate Lipoxygenases; Blood Pressure; Hematocrit; Leukopenia; Lipoxygenase Inhibitors; Male; Naphthoquinones; ortho-Aminobenzoates; Rats; Shock, Septic; Thrombocytopenia; Thromboxane B2