Introduction

Apoptosis is one of the basic characteristics of cells, which plays a very important role in embryonic development, tissue repair and internal environment stability.? In normal cells, phosphatidylserine (PS) is only distributed in the inner side of the lipid bilayer of the cell membrane, but in the early stage of apoptosis, the phosphatidylserine (PS) in the cell membrane flips from the inner side to the outer side.? Annexin ⅴ is a Ca-dependent phospholipid binding protein with a molecular weight of 35-36kD that binds specifically to PS with high affinity during cell apoptosis.??

1 Methods

1.1 Suspended cells were collected by centrifuge, and the centrifuge speed was 2000RPM for 5min. The medium was discarded.

1.2 The cells were washed twice with cold PBS. ?

1.3 The cells were suspended by 400ul 1X Binding Buffer with a concentration of about 1X 10 cells/ mL. ?

1.4 Annexin V-FITC 5ul was added to the cell suspension and was mixed gently. The cells were incubated at 2-8°C under dark conditions for 15 min.??5. Add 10ul PI, mix gently, and incubate at 2-8°C under dark conditions for 5 minutes.??

1.5 Flow cytometry or fluorescence microscopy was used within 1 hour.??