title: Platelet factor 4 protects bone marrow mesenchymal stem cells from acute radiation injury.
abstract: OBJECTIVE
  The aim of this study was to find a new radiation protector, platelet factor 4 (PF4) and to identify its effect on haemopoietic microenvironment in vitro and in vivo.
  
  
  METHODS
  Radiation damage on bone marrow mesenchymal stem cells ex and in vitro was set up as models. Growth curve analysis, clonogenic survival assay, FACSCalibur™ (BD Immunocytometry Systems, San Jose, CA), 5-ethynyl-2'-deoxyuridine immunofluorescence staining and quantitative reverse transcription-polymerase chain reaction were employed to assess the characterization of bone marrow mesenchymal stem cells (BMSCs), proliferation, apoptosis, cell cycle and gene expression.
  
  
  RESULTS
  A dose- and time-dependent enhancement of cell viability and survival was observed for PF4 treatment along with 500 cGy γ-radiation in vitro. The same phenomena were noted in vivo, including enhancement of adherence and proliferation ability while inhibition of cell apoptosis, which were associated with a short-term decrease in the G0/G1 ratio owing to S phase arrest. These were accompanied with enhanced Bcl-2 expression and p53/p21 loss.
  
  
  CONCLUSIONS
  These results uncover that PF4 might be a novel therapeutic approach, which could reduce DNA damage and increase survival of BMSCs, in part, by inhibiting p53/p21 axis and facilitating DNA damage repair.
  
  
  CONCLUSIONS
  This study explores the feasibility of a new radioprotector and hence may be clinically important.
authors.affiliation: 1 Department of Hematology, Tangdu Hospital, Fourth Military Medical University, Xi'an, China.
authors.forename: J-J
authors.initials: JJ
authors.lastname: Chen
authors.forename: Y
authors.initials: Y
authors.lastname: Gao
authors.forename: Q
authors.initials: Q
authors.lastname: Tian
authors.forename: Y-M
authors.initials: YM
authors.lastname: Liang
authors.forename: L
authors.initials: L
authors.lastname: Yang
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000528:radiation effects; D001854:Bone Marrow Cells / Q000187:drug effects / Q000528:radiation effects*; D002453:Cell Cycle / Q000187:drug effects / Q000528:radiation effects; D002455:Cell Division / Q000187:drug effects / Q000528:radiation effects; D049109:Cell Proliferation / Q000187:drug effects / Q000528:radiation effects; D002470:Cell Survival / Q000187:drug effects / Q000528:radiation effects; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000378:metabolism; D004249:DNA Damage; D005720:Gamma Rays; D008297:Male; D059630:Mesenchymal Stem Cells / Q000187:drug effects* / Q000528:radiation effects*; D008810:Mice, Inbred C57BL; D010978:Platelet Factor 4 / Q000494:pharmacology*; D011833:Radiation Injuries, Experimental / Q000517:prevention & control*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013194:Staining and Labeling
chemical_list: D050759:Cyclin-Dependent Kinase Inhibitor p21; D010978:Platelet Factor 4