RESUMO
The aim of this study was to determine how gossypol affects the viability and activity of polymorphonuclear leukocytes and monocytes in blood obtained from healthy donors. Loss of mitochondrial membrane potential (delta psi m) and apoptosis was maximized in human polymorphonuclear leukocytes and monocytes after incubation with gossypol. Pretreatment with a caspase-9 inhibitor or antioxidants (superoxide dismutase or Trolox) inhibited gossypol-induced loss of the delta psi m and apoptosis. Likewise, we observed participation of caspase -3, -7, and -10 in gossypol-induced apoptosis. Expression of the proapoptotic genes bax, bak, bad and p53/Tp53 increased in polymorphonuclear leukocytes exposed to gossypol. The expression of the anti-apoptotic genes bcl-(XL) and mcl-1 was reduced when polymorphonuclear leukocytes and monocytes were treated with gossypol. Gossypol treatment also inhibited yeast phagocytosis by these cells. We concluded that gossypol induces apoptosis in phagocytic cells and that this effect was dose-dependent. The findings in this report may be important to consider in light of possible gossypol use in clinical strategies for cancer treatment.
Assuntos
Apoptose/efeitos dos fármacos , Gossipol/administração & dosagem , Mitocôndrias/efeitos dos fármacos , Monócitos/efeitos dos fármacos , Neutrófilos/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Adulto , Antioxidantes/metabolismo , Caspases/metabolismo , Cromanos/metabolismo , Ciclina D1/biossíntese , Feminino , Humanos , Masculino , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Proteína de Sequência 1 de Leucemia de Células Mieloides , Fagocitose/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-bcl-2/biossíntese , Superóxido Dismutase/metabolismo , Proteína Supressora de Tumor p53/biossíntese , Adulto Jovem , Proteína Killer-Antagonista Homóloga a bcl-2/biossíntese , Proteína X Associada a bcl-2/biossíntese , Proteína de Morte Celular Associada a bcl/biossínteseRESUMO
The in vivo and in vitro development of apoptosis induced by gamma-irradiation was studied in mouse peritoneal macrophages. The apoptosis index was measured by fluorescence microscopy and DNA electrophoresis. In vivo apoptosis was greatest eight days after 8 Gy total body gamma-irradiation. A DNA ladder electrophoretic pattern was only observed in the gamma-irradiated group. The participation of reactive oxygen species in apoptosis induction was investigated by pretreating mice with the antioxidants superoxide dismutase, catalase, vitamin E or lipopolysaccharide before gamma-irradiation. Measurement of serum lipoperoxides showed oxidative stress in the gamma-irradiated mice and the protection given by the antioxidants. These results were confirmed using in vitro cultures of peritoneal macrophages: gamma-irradiated groups and antioxidant-pretreated gamma-irradiation groups showed results similar to those observed with in vivo irradiation. A loss of mitochondrial membrane potential (delta psi(m)) was also observed by microscopy in the gamma-irradiated cell cultures. Experiments with caspase inhibitors confirmed the participation of caspase 3 and caspase 9.