TUNEL Detection of Cell Apoptosis

Cell slides fixed with 4% paraformaldehyde (DF0135, Leagene Biotechnology Co., Ltd., Beijing, China) were washed with Phosphate-Buffered Saline (PBS) (G0002, Servicebio Biotechnology, Wuhan, China). A suitable amount of 0.3% Triton X-100 permeabilization solution (T795, Beyotime Biotechnology, Shanghai, China) was added to the slides. Subsequently, TUNEL staining was performed according to the instructions of the one-step TUNEL apoptosis detection kit (FITC green fluorescence) (G1501, Sevier Biotechnology Co., Ltd., Wuhan, China). Detection solution (TdT enzyme: fluorescent labeling solution= 1:9) was added by drops, and the samples were incubated at 37 °C for 1 hour in the dark. After one cycle of PBS washing, 4ʹ,6-diamidino-2-phenylindole (DAPI) was added in drops to stain for 5 minutes, and slides were dehydrated and mounted with neutral resin (10004160, Sinopharm, Beijing, China). Image acquisition of the slices was conducted using a Mshot inverted microscope (MF53, Guangzhou Mingmei Photoelectric Technology Co., Ltd., Guangzhou, China). The nuclei of apoptotic cells emitted green fluorescence, while the DAPI-stained nuclei emitted blue fluorescence.