In vitro toxicity of multi-walled carbon nanotubes in C6 rat glioma cells.

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.