title: Reduction of osteocalcin expression in aged human dental pulp.
abstract: OBJECTIVE
  To investigate the expression of osteocalcin mRNA in young and in aged human dental pulp tissue to determine the characteristics of osteocalcin expression.
  
  
  METHODS
  Human dental pulp tissues of the third molars were obtained from healthy young (17-23 years) and aged (>50 years) subjects, and total RNA was extracted. Osteocalcin mRNA expression was determined by RT-PCR and by quantitative real-time RT-PCR (QRT-PCR). The threshold cycle (Ct) value, which reflects the amount of PCR, was calculated and the difference between the value in young and aged pulp was statistically analysed.
  
  
  RESULTS
  Osteocalcin mRNA was detected in all samples of human dental pulp tissue homogenates by RT-PCR analysis. Osteocalcin mRNA was expressed in young adult dental pulp but was decreased in aged human dental pulp. QRT-PCR analysis also showed a reduced expression of osteocalcin mRNA in aged human pulp. Expression of osteocalcin in young human pulp was significantly higher (about sixfold) than in aged pulp (P<0.01, Mann-Whitney U-test).
  
  
  CONCLUSIONS
  Reduction of osteocalcin expression may be associated with the loss of viability in human dental pulp tissue, and may be a characteristic of aged human dental pulps.
authors.affiliation: Oral Health Science Center, Tokyo Dental College, Chiba, Japan. tmuramat@tdc.ac.jp
authors.forename: T
authors.initials: T
authors.lastname: Muramatsu
authors.forename: H
authors.initials: H
authors.lastname: Hamano
authors.forename: K
authors.initials: K
authors.lastname: Ogami
authors.forename: K
authors.initials: K
authors.lastname: Ohta
authors.forename: T
authors.initials: T
authors.lastname: Inoue
authors.forename: M
authors.initials: M
authors.lastname: Shimono
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000375:Aging / Q000235:genetics / Q000378:metabolism*; D003782:Dental Pulp / Q000378:metabolism*; D005260:Female; D005786:Gene Expression Regulation; D006801:Humans; D008297:Male; D008875:Middle Aged; D015675:Osteocalcin / Q000032:analysis* / Q000235:genetics; D012333:RNA, Messenger / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014022:Tissue Survival / Q000235:genetics
chemical_list: D012333:RNA, Messenger; D015675:Osteocalcin