ABSTRACT
Reported here are the results of a study carried out in order to assess the possible influence of the major circulating active metabolite of nabumetone, 6-methoxy-2-naphthylacetic acid, on some aspects of polymorphonuclear leukocytes activation. The action of 6-methoxy-2-naphthylacetic acid was tested on the following features of polymorphonuclear leukocytes activation: reactive oxygen species production in polymorphonuclear leukocytes stimulated with different agonists, reactive oxygen species production in polymorphonuclear leukocytes treated with pertussis toxin, NADPH-oxidase activity. The findings showed that 6-methoxy-2-naphthylacetic acid decreased reactive oxygen species production in polymorphonuclear leukocytes stimulated with N-formyl-methionyl-leucyl-phenylalanine, phorbol myristate acetate, and opsonized zymosan, but failed to provoke a decrease of reactive oxygen species production when the cells were stimulated with calcium ionophore A23187. Moreover, 6-methoxy-2-naphthylacetic acid did not influence the transduction of the signal following the binding of stimuli to membrane receptors, and NADPH-oxidase activity. Finally, our findings showed that 6-methoxy-2-naphthyl acetic acid had no scavenger effect on reactive oxygen species production.
Subject(s)
Anti-Inflammatory Agents, Non-Steroidal/metabolism , Butanones/metabolism , Naphthaleneacetic Acids/pharmacology , Neutrophils/drug effects , Free Radical Scavengers , Humans , In Vitro Techniques , Luminescent Measurements , NADH, NADPH Oxidoreductases/blood , NADPH Oxidases , Nabumetone , Pertussis Toxin , Virulence Factors, Bordetella/pharmacologyABSTRACT
The aim of this research was to evaluate in vitro interactions between platelets and polymorphonuclear leukocytes. The effects of supernatant from thrombin-activated platelets and two platelet release products (adenosine triphosphate and beta-thromboglobulin) were tested on the following features of polymorphonuclear leukocytes activation: opsonized zymosan and phorbol myristate acetate stimulated chemiluminescence, release of membrane bound calcium, NADPH-oxidase activity, and membrane fluidity (fluorescent polarization). The results showed that the addition of platelet supernatant to polymorphonuclear leukocytes induces a significant activation of cells. On the other hand, after three hours of preincubation of polymorphonuclear leukocytes with platelet supernatant, a decreased response of polymorphonuclear leukocytes to stimulation with phorbol myristate acetate, a significant decrease in NADPH-oxidase activity, and a lowered membrane fluidity were observed. Adenosine triphosphate modulated only opsonized zymosan stimulated chemiluminescence, with and without preincubation with polymorphonuclear leukocytes. Beta-thromboglobulin caused a decrease of the chemiluminescent response of polymorphonuclear leukocytes, using both agonists, with and without preincubation with polymorphonuclear leukocytes. Moreover beta-thromboglobulin only caused a decrease of the polymorphonuclear leukocytes membrane fluidity without preincubation with the cells. These results support the thesis that platelets have a "time-related" modulating activity on polymorphonuclear leukocytes.
Subject(s)
Neutrophils/physiology , Platelet Activation/physiology , Adenosine Triphosphate/pharmacology , Calcium/metabolism , Fluorescence Polarization , Humans , Luminescent Measurements , Membrane Fluidity/drug effects , Membrane Fluidity/physiology , Membranes/metabolism , NADH, NADPH Oxidoreductases/analysis , NADPH Oxidases , Neutrophils/drug effects , Platelet Activation/drug effects , Tetradecanoylphorbol Acetate/pharmacology , Thrombin/pharmacology , Zymosan/pharmacology , beta-Thromboglobulin/pharmacologyABSTRACT
The aim of this paper was to evaluate the "in vitro" interaction between beta-thromboglobulin, one specific platelet release product and polymorphonuclear leukocytes. The effects of beta-thromboglobulin were tested on the following features of polymorphonuclear leukocytes activation: opsonized zymosan and phorbol myristate acetate stimulated chemiluminescence, release of membrane bound calcium, NADPH-oxidase activity, and membrane fluidity. Beta-thromboglobulin caused a decrease of the chemiluminescent response of polymorphonuclear leukocytes, using both agonists, with and without preincubation with polymorphonuclear leukocytes. We observed that beta-thromboglobulin caused a decrease also in the activity of NADPH-oxidase but not in the release of membrane bound calcium. Moreover beta-thromboglobulin caused a decrease of the polymorphonuclear leukocytes membrane fluidity. Our results suggest that the beta-thromboglobulin could play a role in the reciprocal interactions between platelets and polymorphonuclear leukocytes.
