Orientador: Edson Antunes

Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas

Resumo: Poliaminoácidos básicos tais como a polilisina e poliarginina produzem uma variedade de efeitos biológicos incluindo aumento da permeabilidade vascular, infiltração de leucócitos, inflamação pulmonar, agregação de plaquetas e ativação de mastócitos. Neste estudo, investigamos os mecanismos...

Resumo: Poliaminoácidos básicos tais como a polilisina e poliarginina produzem uma variedade de efeitos biológicos incluindo aumento da permeabilidade vascular, infiltração de leucócitos, inflamação pulmonar, agregação de plaquetas e ativação de mastócitos. Neste estudo, investigamos os mecanismos envolvidos na desgranulação de mastócitos induzida por poliarginina e polilisina usando-se mastócitos peritoneais isolados de ratos. Mastócitos de 10 ratos machos Wistar (200 a 300 g) foram obtidos por injeção de solução Krebs Ringer Fosfato (KRF) na cavidade peritoneal. O lavado peritoneal foi removido e centrifugado a 300 9 por 5 minutos à temperatura ambiente. A suspensão de células foi lavada com KRF e incubada com C4C]serotonina (C4C]5-HT; 40 nCi/ml) por 60 minutos. As células foram então lavadas 3 vezes em KRF. Alíquotas da suspensão celular foram
aqueci das a 37°C por 20 minutos. Os agentes desgranuladores foram adicionados à suspensão. As células foram então centrigugadas (300 g, 10 minutos) e o sobrenadante removido para determinação da C4C]5-HT. A concentração de C4C]5-HT (%) foi determinada medindo-se a cintilação em contador f3 ...Observação: O resumo, na íntegra, poderá ser visualizado no texto completo da tese digital

Abstract: Basic polyaminoacids such as polylysine and polyarginine produce a variety of biological effects including increase in vascular permeability, leucocytic infiltration, lung infllammation, platelet aggregation and mast cell activation. In this study we have further investigated the...

Abstract: Basic polyaminoacids such as polylysine and polyarginine produce a variety of biological effects including increase in vascular permeability, leucocytic infiltration, lung infllammation, platelet aggregation and mast cell activation. In this study we have further investigated the mechanisms involved in the mast cell degranulation induced by polyarginine and polylysine using isolated rat peritoneal mast cells. Mast cells of 10 male Wistar rats (200 - 300 g) were obtained by the injection of Krebs-Ringer Phosphate solution (KRP) into peritoneal cavity. The fluid was withdrawn and centrifuged at 300 9 for 5 min at roem temperaature. The cell suspension was washed twice in KRP and incubated with 40 nCi/ml of C"C]5-HT at 37C by 60 min. The cells were then washed three times in KRP. Aliquots of the peritoneal cell suspension were warmed at 37°C for 20 mino The stimulus were added to the suspension. The cells were then centrifuged (300 g, 10 min) aand the supematant removed for [1"C]5-HT determination. The [1"C]5
HT concentrations (%) was determined by measuring the radioactivity in a y counter. Poly-l-arginine caused a dose-dependent C"C]5-HT release (139.2 kD; 11 :t 5, 67 :t 4.4 and 70.4 :t 0.6% for 0.01, 0.1 and 1J,LM, respectively; n = 4). Similar responses were observed for either poly-D-Iysine (94.9 kD; 4 :t 0.6, 28 :t 6 and 41 :t 14 for 0.01,0.1 and 1 IlM, respectively; n = 4) and poly-l-Iysine (80.4 kD; 30 :t 1 and 61 :t 3.3% for 0.1 and 1 J,LM, respectively; n=12). The polyarginine-induced C4C]5-HT release was also dependent on the molecular weight of the polycation (5 1: 2 and 27 1: 7% for 11.6 kD and 139.3 kD, respectively; n = 6). Heparin (15 - 250 U/ml) and dermatan sulfate (0.1 mg I ml) virtually abolished the [14C] 5-HT release induced by polyarginine. In contrast,
the enzymes chondroitinase AC, heparitinase I, heparitinase 11 and heparinase had no effect on the polyarginine-induced [14C] 5-HT release