2.9. Assay of SOD, CAT, and GSH-Px activities

The enzymatic activities were all determined by assay kits (Beyotime). For the determination of superoxide dismutase (SOD) activity, the 2-(4-iodophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium (WST-1) method was used, where in the SOD activity can be calculated by measuring the absorbance of formazan dye at 450 nm. The assay for catalase (CAT) was based on its ability to scavenge H2O2. Glutathione peroxidase (GSH-Px) catalyst activity was assayed by quantifying the rate of oxidation of the reduced glutathione to the oxidized glutathione by H2O2. As such, cells (1×106 mL-1 at passage 4) were plated in 60 mm petri dishes. After 0 or 100 mM trehalose treatment for 24 h, cells were washed twice in ice-cold PBS and homogenized. The homogenate was centrifuged for 10 min at 10 000 rpm at 4 ∘C, and supernatant was used for determining SOD, CAT, and GSH-Px activities according to the manufacturer's instructions.