KIT and Bone marrow hypocellularity: In the mouse, HSCs can be isolated by their expression of undetectable levels of lineage markers (such as B220, CD3, Mac‐1) and high levels of c‐Kit and Sca‐1, which are known as the LSK cells.21 If HSC are injured by irradiation, long‐term, or permanent damage to the haematopoietic system occurs and bone marrow failure and death of the organism may occur.22 In the study, we examined whether FG‐4592 could protect HSCs from irradiation‐induced injury.