Effect of colloidal silver against the cytotoxicity of hydrogen peroxide and naphthazarin on primary cultured cortical astrocytes.

One major pathogenesis in degenerative disorders of the central nervous system (CNS), including Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, and ischemia, is the oxidative stress induced by reactive oxygen species (ROS). The present study investigated the protective effect of colloidal silver, which is widely marketed as a dietary supplement for diseases like diabetes, AIDS, cancer, and various infections, upon the oxidative brain damage induced by H(2)O(2) or naphthazarin treatment. LDH release from primary cultured astrocytes was enhanced by naphthazarin treatment, and this elevation of the LDH concentration in medium was blocked by colloidal silver treatment. However, hydrogen peroxide was little affected by the colloidal silver. Fluorescence of DCF (peroxides) increased in astrocytes incubated with hydrogen peroxide or naphthazarin compared to the control. When exposed to naphthazarin-induced cells, ROS formation appeared to be reduced by colloidal silver. However, intracellular ROS formation in hydrogen peroxide-treated cells slightly reduced by colloidal silver. These results suggest that colloidal silver has a protective activity against the oxidative stress induced by naphthazarin, but not by hydrogen peroxide.