Applications of synthetic nanoparticles in wide variety of industries are identified to be growing at a faster rate. The potential effects of nano-silicon dioxide and its toxic mechanisms remain unclear. In the present study 5 mg/ L concentration of silicon dioxide nanoparticles were exposed to the freshwater fish, Oreochromis mossambicus for 24 h, 48 h and 96 h. The body weight remained unchanged whereas the hepatosomatic index showed a significant decrease at 96 h. The percentage of mucous secretion was comparatively high in all treatment groups. The activity of superoxide dismutase, catalase, glutathione reductase altered significantly in hepatocytes after 48 h and 96 h. However, the levels of hydrogen peroxide and lipid peroxidation showed a significant increase in treated groups than the control. Alkaline phosphatase, liver marker enzymes showed a significant decrease throughout the exposure. Thus the study revealed that exposure to silicon dioxide nanoparticle generates reactive oxygen species in fish hepatocytes and this could be due to the potential harmful impact of the nanoparticle.
