4.17. Caspase 3 and Caspase 9 Activity Assay

The activation of caspases was detected using colorimetric assay kits (BioVision, Palo Alto, CA, USA). Briefly, cortical neurons were harvested and lysed on ice for 15 min. After centrifugation, the resulting supernatants were collected as fresh 1.5 mL centrifuge tubes for protein concentration assay. Then, the labeled substrates DEVD-pNA and LEHD-pNA were used to assess the activity of caspase 3 and caspase 9, respectively. The absorbance of pNA catalyzed by caspases in the sample was measured at 405 nm using a microplate reader (Biotek, Winooski, VT, USA).