title: Differential expression of pluripotent and germ cell markers in ovarian surface epithelium according to age in female mice.
abstract: BACKGROUND
  Many studies have proposed that putative ovarian stem cells (OSCs) derived from the ovarian surface epithelium (OSE) layer of adult mammalian ovaries can produce oocytes. Few studies have reported that ovaries of aged mammalian females including mice and women possess rare premeiotic germ cells that can generate oocytes. However, no studies have reported the changes of OSCs according to the age of the female. Therefore, this study evaluated pluripotent and germ cell marker expression in the intact ovary, scraped OSE, and postcultured OSE according to age in female mice.
  
  
  METHODS
  C57BL/6 female mice of 2 age groups (6-8 and 28-31 weeks) were superovulated by injection with 5 IU equine chorionic gonadotropin (eCG). Both ovaries were removed after 48 hours and scrapped to obtain OSE. Gene expressions of pluripotent (Oct-4, Sox-2, Nanog) and germ cell markers (c-Kit, GDF-9, and VASA) were evaluated by RT-PCR. VASA and GDF-9 were immune-localized in oocyte-like structures.
  
  
  RESULTS
  Expressions of germ cell markers in the intact ovary were significantly decreased in aged females, whereas expressions of pluripotent markers were not detected, regardless of age. Scraped OSE expression of all pluripotent and germ cell markers, except for c-Kit, was similar between both age groups. Three weeks postcultured OSE had significantly decreased expression of GDF-9 and VASA , but not c-Kit, in old mice, as compared to young mice; however there was no difference in the expression of other genes. The number of positively stained Oct-4 by immunohistochemistry in postcultured OSE was 2.5 times higher in young mice than aged mice. Oocyte-like structure was spontaneously produced in postcultured OSE. However, while that of young mice revealed a prominent nucleus, zona pellucida-like structure and cytoplasmic organelles, these features were not observed in old mice.
  
  
  CONCLUSIONS
  These results show that aged female mice have putative OSCs in OSE, but their differentiation potential, as well as the number of OSCs differs from those of young mice.
authors.forename: Bo Sun
authors.initials: BS
authors.lastname: Joo
authors.forename: In Kook
authors.initials: IK
authors.lastname: Jung
authors.forename: Min Jung
authors.initials: MJ
authors.lastname: Park
authors.forename: Jong Kil
authors.initials: JK
authors.lastname: Joo
authors.forename: Ki Hyung
authors.initials: KH
authors.lastname: Kim
authors.affiliation: Department of Obstetrics and Gynecology, Medical Research Institute, Pusan National University School of Medicine, Busan, Korea. kuslee@pusan.ac.kr.
authors.forename: Kyu-Sup
authors.initials: KS
authors.lastname: Lee
mesh_terms: D000367:Age Factors; D000375:Aging / Q000235:genetics*; D000818:Animals; D002467:Cell Nucleus / Q000378:metabolism; D002478:Cells, Cultured; D006063:Chorionic Gonadotropin / Q000494:pharmacology; D053487:DEAD-box RNA Helicases / Q000235:genetics / Q000378:metabolism; D004847:Epithelial Cells / Q000378:metabolism*; D005260:Female; D055429:Growth Differentiation Factor 9 / Q000235:genetics / Q000378:metabolism; D018398:Homeodomain Proteins / Q000235:genetics; D006736:Horses; D007150:Immunohistochemistry; D008810:Mice, Inbred C57BL; D000071317:Nanog Homeobox Protein; D050814:Octamer Transcription Factor-3 / Q000235:genetics / Q000378:metabolism; D009865:Oocytes / Q000166:cytology / Q000378:metabolism*; D010053:Ovary / Q000166:cytology / Q000187:drug effects; D039904:Pluripotent Stem Cells / Q000166:cytology / Q000378:metabolism*; D019009:Proto-Oncogene Proteins c-kit / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D055748:SOXB1 Transcription Factors / Q000235:genetics; D013480:Superovulation / Q000187:drug effects; D059467:Transcriptome
chemical_list: D006063:Chorionic Gonadotropin; D055429:Growth Differentiation Factor 9; D018398:Homeodomain Proteins; D000071317:Nanog Homeobox Protein; C475540:Nanog protein, mouse; D050814:Octamer Transcription Factor-3; C494174:Pou5f1 protein, mouse; D055748:SOXB1 Transcription Factors; C527783:Sox2 protein, mouse; D019009:Proto-Oncogene Proteins c-kit; C090864:Ddx4 protein, mouse; D053487:DEAD-box RNA Helicases