TUNEL Assay

Apoptotic cells were tested by TUNEL assay, the brain tissues and cells were prepared as previously described. In brief, the TUNEL reaction mixture of enzyme solution and labeling solution was added at a ratio of 1:9 (v/v), and the slices of cells were stored at 4°C overnight in the dark. After three washes with PBS, the slices were stained with DAPI for 5 min at room temperature, and images were observed via high-content imaging system (Evons, Thermo, United States). Sixteen fields were randomly selected from each section, and apoptosis was quantified by determining the percentage of TUNEL/DAPI using high-content quantitative system.