Determination of malondialdehyde (MDA) levels

The MDA levels in the brain sample were assayed using a Lipid Peroxidation (MDA) Assay Kit (Sigma-Aldrich Co.) according to the manufacturer's protocols. Briefly, 45 mg cortex and 5 mg hippocampus tissue from each group of mice were homogenized in MDA lysis buffer containing butylhydroxytoluene (BHT), after which the homogenates were stored at -20℃ until analysis. The sample or standards and TBA solution (70 mM thiobarbituric acid and 5M glacial acetic acid) were incubated at 95℃ for 60 min, then cooled to room temperature in an ice bath for 10 min, after which the reaction absorbance at 532 nm was read using a Versa max plate reader (Molecular Devices).