title: [Effect of chemical microenvironment after traumatic brain injury on temperature-sensitive umbilical cord mesenchymal stem cells].
abstract: OBJECTIVE
  To simulate the chemical microenvironment of injured brain tissue, and to explore the effect of this chemical microenvironment on temperature sensitive umbilical cord mesenchymal stem cells (tsUC).
  
  
  METHODS
  Rat models of traumatic brain injury (TBI) were made by fluid percussion injury, and then the brain tissue extracts of the injured regions were acquired. Human umbilical cord mesenchymal stem cells (UC) were isolated and cultured, and the tsUC were obtained through the infection of temperature-sensitive Simian 40 Large T- antigen (ts-SV40LT) retrovirus. After that, both the two kinds of cells were cultured on the polyacrylamide gels which mimicking the elastic modulus of brain. Four groups were included: UC cultured under normal temperature (UC group), UC cultured added brain tissue extract under normal temperature (UC plus extract group), tsUC cultured under mild hypothermia (tsUC group), and tsUC added brain tissue extract under mild hypothermia for 3 days, then normal temperature for 4 days (tsUC plus extract group). After 24 hours, the apoptosis level was checked. Cell growth and morphological changes in each group were given dynamic observation. Seven days later, cell immunofluorescences were implemented for examining neural differentiation level.
  
  
  RESULTS
  Compared with UC plus extract group, the apoptosis and proliferation in UC plus extract group were significantly reduced (P < 0.01) and increased (P < 0.01) respectively. Cell immunofluorescence showed that the both GFAP and Neuron positive cells were significantly enhanced in UC plus extract group than those in tsUC plus extract group.
  
  
  CONCLUSIONS
  tsUC combining with mild hypothermia could significantly reverse injury induced cell apoptosis, improve cell proliferation and neural differentiation under chemical microenvironment after brain injury, which confirmed the adaptation and resistance of tsUC under mild hypothermia after TBI.
authors.forename: Ming-liang
authors.initials: ML
authors.lastname: Zhao
authors.forename: Yi-sheng
authors.initials: YS
authors.lastname: Chen
authors.forename: Xiao-hong
authors.initials: XH
authors.lastname: Li
authors.forename: Jing-jing
authors.initials: JJ
authors.lastname: Wang
authors.forename: Yue
authors.initials: Y
authors.lastname: Tu
authors.forename: Hong-tao
authors.initials: HT
authors.lastname: Sun
authors.forename: Sai
authors.initials: S
authors.lastname: Zhang
authors.forename: Chonga
authors.initials: C
authors.lastname: Chen
mesh_terms: D000818:Animals; D017209:Apoptosis; D001921:Brain / Q000166:cytology / Q000473:pathology*; D001930:Brain Injuries / Q000473:pathology*; D049109:Cell Proliferation; D006801:Humans; D059630:Mesenchymal Stem Cells / Q000737:chemistry*; D009474:Neurons / Q000166:cytology; D051381:Rats; D013696:Temperature; D014470:Umbilical Cord / Q000166:cytology