2.8. Analysis of Catalase (CAT) Activity

CAT activity in the brain cortex tissue was assessed using the EZ-Catalase assay kit (DoGenBio, Seoul, Korea). After the preparation of brain tissue homogenates, a volume of 25 μL of brain sample was mixed with 25 μL of H₂O₂ solution. Subsequently, Oxi-Probe/Horseradish peroxidase solution (100 μM and 0.4 Units/mL dissolved in 1× reaction buffer, pH 7.5) was added to each well and incubated at room temperature for 30 min in the dark. The activity was monitored by measuring fluorescent intensity using a Glomax microplate reader (Promega, Madison, WI, USA). Results were corrected by protein concentration determined with BCA protein assay (Thermo Scientific, Rockford, IL, USA), and expressed as units per mg of brain protein. One unit of catalase was defined as 1 μmol H₂O₂ decomposed per min.