RESUMO
The present study aimed to evaluate the potential toxicity and the general mechanism involved in multi-walled carbon nanotubes (MWCNT)-induced cytotoxicity in C6 rat glioma cell line. Two kinds of MWCNT, which were coded as MWCNT1 (measured 10-20 nm in diameter and 2 µm in average length) and MWCNT2 (measured 40-100 nm in diameter and 10 µm in average length), were used in this study. To elucidate the possible mechanisms of cytotoxicity induced by MWCNT, MTT assay and flow cytometry analysis for apoptosis and cell cycle, MDA and SOD assays for oxidative stress were quantitatively assessed. The exposure of C6 rat glioma cells to different sizes of two kinds of carbon nanotubes at concentrations between 25 and 400 µg/ml decreased the cell viability in a concentration- and time-dependent manner. The exposure of C6 rat glioma cells to MWCNT (200-400 µg/ml) resulted in a concentration dependent cell apoptosis and G1 cell cycle arrest, and increased the level of oxidative stress. Results demonstrate that smaller size of MWCNT seems to be more toxic than that of larger one. MWCNT-induced cytotoxicity in C6 cells is probably due to the increased oxidative stress.
Assuntos
Apoptose/efeitos dos fármacos , Nanotubos de Carbono/toxicidade , Estresse Oxidativo/efeitos dos fármacos , Análise de Variância , Animais , Anexina A5/metabolismo , Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Citometria de Fluxo , Glioma/patologia , Microscopia Eletrônica de Transmissão , Nanotubos de Carbono/classificação , Nanotubos de Carbono/ultraestrutura , Propídio , Ratos , Fatores de TempoRESUMO
The effects of nano particles of CuO on voltage-dependent potassium currents were studied in acutely isolated CA1 pyramidal neurons of rat hippocampus using the whole-cell patch-clamp techniques. Nano particles of CuO had small effects on transient outward potassium current (I(A), no statistical significance) and mainly inhibited delayed rectifier potassium current (I(K)) in the concentration of 5 x 10(-5) g/mL. Nano particles of CuO didn't shift the steady-state activation curve of I(K) and I(A) but negatively shifted the inactivation curve of I(K). The effects on inactivation curve of I(A) had no statistical significance. These results suggested that blockades of K+ currents by nano particles of CuO could be preferential for I(k) for the first time. This may interfere with the normal function of nerve cells.
