The splenic toxicity of water soluble multi-walled carbon nanotubes in mice

Spleen is an important immune organ and a constituting part of the reticuloendothelial system (RES). CNTs in vivo can be readily scavenged from blood and mainly entrapped by liver, spleen and lungs. Herein, water soluble multi-walled carbon nanotubes (S-MWCNTs) were used as a model to investigate the possible toxicity of carbon nanotubes (CNTs) to mouse spleen. The toxicity of various doses of S-MWCNTs was examined by carbon clearance measurement, oxidative stress assay, histopathologic and electron-microscopic examination. Compared with the control group, phagocytic activity of RES, activity of reduced glutathione, superoxide dismutase and malondialdehyde in splenic homogenate did not change significantly in 2 months. The histopathologic examination showed no observable sign of damage in spleen; however, the accumulated S-MWCNTs gradually transferred from the red pulp to the white pulp over the exposure time and might initiate the adaptive immune response of spleen.