Avaliação dos efeitos de compostos orgânicos de selênio e de telúrio sobre a integridade estrutural e funcional de células sangüíneas humanas

Abstract

In view of the need to expand the toxicologic studies of organochalcogens in biological systems, the aim of this study was to investigate the effect of exposure to organic compounds of selenium (Se) and tellurium (Te) on the structural and functional integrity of human cells in vitro. The erythrocytes and leukocytes cells were isolated and incubated with the vehicle or different compounds of Se and Te at concentrations of 50, 75 and 100 μM. After the incubation period, the structural and functional integrity of erythrocytes were evaluated through the osmotic fragility test, Na+/K+ ATPase and catalase activities, reactive oxygen species and SH levels. In leukocytes was verified the cell viability and DNA damage. The results showed that the hemolysis, measured through the test of osmotic fragility, was significantly increased in erythrocytes exposed to the compound diphenyl selenide (II), diphenyl diselenide (III), diphenyl telluride (IV), diphenyl ditelluride (V ), (S)-2-amino-1-diselenide-3-methylpropanyl (IX), butyl (styryl) telluride (XIII) and 2 - (butyltellurium) furan (XIV) when compared to controls. The organic compounds II and XIII, that had greater hemolytic effect, did not alter the activity of catalase and reactive oxygen species (ROS) and SH levels. However, these compounds caused a significant inhibition on the activity of the enzyme Na+/K+ ATPase in a concentration dependent manner. This inhibition was totally reversed by addition of DTT, showing that the organochalcogens have affinity for thiol groups of the enzyme. Moreover, the rate of oxidation of DTT was significantly increased in the presence of both compounds, suggesting a thiol oxidase activity. Indeed, the compounds II and XIII were genotoxic and cytotoxic to human leukocytes.