title: [Reactive oxygen species mediate the injury and deficient hematopoietic supportive capacity of umbilical cord derived mesenchymal stem cells induced by iron overload].
abstract: OBJECTIVE
  To explore the effects of iron overload on umbilical cord derived mesenchymal stem cells (UC-MSC) and elucidate the involvement of reactive oxygen species (ROS) in this process.
  
  
  METHODS
  The iron overload model of MSC was established by in vitro addition of ferric ammonium citrate (FAC) into culture medium. Cell proliferation and apoptosis were determined by Annexin V/PI double staining and population doubling time (DT) respectively. Co-culture system was used to assess the hematopoietic support capacity of UC-MSC in different groups. Thereafter the ROS level was detected with fluorescent probe 2', 7'-dichlorofluorescin diacetate (DCFH-DA). And the ROS related signaling factors of p-p38MAPK, p38 MAPK, P53 were measured by Western blot.
  
  
  RESULTS
  (1) The DT of UC-MSC in iron overload group was significantly longer than that of control ((24.43 ± 2.72) h vs (16.03 ± 2.31) h, P < 0.05). But the difference was insignificant after two passages (P > 0.05). (2) Apoptosis in iron overload group was higher than that of control (12.75% ± 0.32% vs 3.63% ± 0.80%, P < 0.05). (3) The colony forming capacity of mononuclear cell (MNC) co-cultured with UC-MSC of iron overload group for 1/2 weeks significantly decreased. (4) The ROS level of UC-MSC with iron overload was higher than that of control in time and concentration-dependent fashions and it peaked at 400 µmol/L of FAC for 12 h (1499 ± 86 vs 548 ± 97, P < 0.05). (5) The expressions of p-p38MAPK and P53 increased in response to FAC compared with control. But such an effect was partially inhibited after the use of antioxidants.
  
  
  CONCLUSIONS
  Iron overload may impair the proliferation, survival and hematopoiesis supportive function of UC-MSC by enhancing the generation of ROS. And ROS stimulates the signaling pathways of p-p38MAPK and P53.
authors.affiliation: Department of Hematology & Oncology, Tianjin Medical University, Tianjin, China.
authors.forename: Wen-yi
authors.initials: WY
authors.lastname: Lu
authors.forename: Ming-feng
authors.initials: MF
authors.lastname: Zhao
authors.forename: Xiao
authors.initials: X
authors.lastname: Chai
authors.forename: Juan-xia
authors.initials: JX
authors.lastname: Meng
authors.forename: Nan
authors.initials: N
authors.lastname: Zhao
authors.forename: Sajin
authors.initials: S
authors.lastname: Rajbhandary
authors.forename: Xin-nü
authors.initials: XN
authors.lastname: Xu
authors.forename: Li
authors.initials: L
authors.lastname: Ma
authors.forename: Yu-ming
authors.initials: YM
authors.lastname: Li
mesh_terms: D049109:Cell Proliferation; D002478:Cells, Cultured; D003470:Culture Media; D006413:Hematopoietic System; D006801:Humans; D019190:Iron Overload; D059630:Mesenchymal Stem Cells / Q000166:cytology*; D017382:Reactive Oxygen Species / Q000378:metabolism*; D015398:Signal Transduction; D014470:Umbilical Cord / Q000166:cytology
chemical_list: D003470:Culture Media; D017382:Reactive Oxygen Species