Nanosized
colloidal silver (NCS) with primary nanoparticles (NPs) size in the range of 10-80 nm in aqueous
suspension was administered to rats with initial weight 80±10 gfor the first 30 day intragastrically and for lasting 62 days with the diet consumed in doses of 0.1; 1.0 and 10 mg/kg of
body weight b.w) per day based on
silver (Ag). The control animals received deionized water and carrier of NPs - aqueous
solution of stabilizer
polyvinylpyrrolidone. Activity (Vmax) was determined in liver of microsomal mixed function
monooxygenase isoforms CYP 1A1, 1A2 and 2B1 against their specific substrates, the activity of liver conjugating
enzymes (
glutathione-S-transferase and
UDP-glucuronosyltransferase) in the microsomal fraction and a cytosol, and the overall and non-sedimentable activities of lysosomal
hydrolases. In blood plasma there were evaluated malonic dialdehyde, PUFA diene conjugates, in erythrocytes - the activity of
antioxidant enzymes. A set of standard biochemical indicators of blood serum was also determined. The studies revealed changes in a number of molecular markers of
toxic action. Among them - the increase in the activity of key
enzymes I and II stages of detoxification of
xenobiotics, indicating its functional overvoltage; reducing the activity of
glutathione peroxidase (GP), the total
arylsulfatase A and B, β-
galactosidase (in the absence of changes in their non-sedimentable activity), levels of
uric acid, increased
alkaline phosphatase activity. These changes occurred mainly at the dose Ag of 10 mg/kg b.w., except for the GP to which the threshold dose was 1 mg/kg b.w. No significant changes in the studied markers in a dose Ag 0,1 mg/kg b.w. were identified. Possible mechanisms of the
toxic action of
silver NPs are discussed.