title: Comparing the cultivated cochlear cells derived from neonatal and adult mouse.
abstract: BACKGROUND
  Previous reports showed the presence of limited numbers of stem cells in neonatal murine cochlear sensory epithelia and these cells are progressively lost during the postnatal development. The goal of this study was to investigate whether stem cells can be derived from mature mouse cochleae under suspension culture conditions, and to analyze the expression of the stem cell and inner ear progenitor cell markers in cells dissociated from neonatal and adult mouse organs of Corti.
  
  
  METHODS
  Organs of Corti were dissected from postnatal day 1 (P1) or postnatal day 60 (P60) mouse. The dissociated cells were cultivated under suspension cultures conditions. Reverse transcription-polymerase chain reaction (RT-PCR) and immunocytochemistry were conducted for phenotype characterization.
  
  
  RESULTS
  The number of cochlear stem cells (otospheres) yielded from P1 organ of Corti was significantly higher than that of the P60 organ of Corti. RT-PCR analyses showed that the stem markers, such as nanog, sox2, klf4, and nestin can be found to be distributed similarly in the cells derived from both of organisms, but the inner ear developmental/progenitor cell markers showed lower expression in P60 organ of Corti compared to P1. Immunocytochemistry results also revealed the evidence that P60 otospheres lacking of differentiation potential in vitro, which opposed to the strong differentiation potential of otospheres at P1 stage.
  
  
  CONCLUSIONS
  Our findings suggest that the loss of numbers and features of stem cells in the adult organ of Corti is associated with the substantial down-regulation of inner ear progenitor key-markers during maturation of the cells in organ of Corti.
authors.forename: Xiangxin
authors.initials: X
authors.lastname: Lou
authors.forename: Youyi
authors.initials: Y
authors.lastname: Dong
authors.forename: Jing
authors.initials: J
authors.lastname: Xie
authors.forename: Xianliu
authors.initials: X
authors.lastname: Wang
authors.forename: Liangliang
authors.initials: L
authors.lastname: Yang
authors.forename: Masaaki
authors.initials: M
authors.lastname: Tokuda
authors.affiliation: Department of Bioengineering, College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, 2999 North Renmin Road, Shanghai 201620, China. yzzhang@dhu.edu.cn.
authors.forename: Yanzhong
authors.initials: Y
authors.lastname: Zhang
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001483:Base Sequence; D049109:Cell Proliferation; D002478:Cells, Cultured; D017931:DNA Primers; D000090062:Kruppel-Like Factor 4; D051379:Mice; D009925:Organ of Corti / Q000166:cytology*; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D017931:DNA Primers; C000715468:Klf4 protein, mouse; D000090062:Kruppel-Like Factor 4