Exposure to carbon nanotubes may induce cytotoxicity and increase protein expression of Bax in mouse skin fibroblasts

Abstract

Background: Discovery of carbon nanotubes is one of the greatest discoveries in nanotechnology. Carbon nanotubes are used in many applications in modern technology, however the related risks of long-term toxicity of those materials remain to be elucidated.Since we are widely exposed to nanoparticles and the main mechanism of nanoparticles toxicity is not yet known, the effect of carbon nanotubes on cell viability and the possible mechanism in mouse skin fibroblasts was investigated.Methods: Cytotoxicity of characterized-carbon nanotubes on cell viability was examined by MTT assay. Intracellular generation of ROS was measured by fluorometric and lactate secretion was determined by photometric method. Western blot analysis was used for detection of Bax as a key factor in apoptosis pathway.Results: MTT results showed a significant decreased in cell viability and also increase of ROS generation was observed in fibroblast treated with carbon nanotubes. Western blot analysis revealed a significant increase of Bax as a key protein in apoptosis, reflecting the effects of carbon nanotubes on cell death. Cellular lactate secretion, as a necessary component for fibroblast proliferation and collagen synthesis, showed a significant decreased in cells treated with carbon nanotubes.Conclusion: Consequently, both carbon nanotubes should be considered as the potential toxic substances for skin fibroblasts which is the body's first line of defense. Carbon nanotubes by increasing ROS and Bax may induce apoptosis in fibroblasts via Bax apoptotic-pathways. Also, suppression of lactate generation could reduce collagen production which may speed up aging process especially in the skin.