title: Proliferation and differentiation of progenitor cells throughout the intact adult rat spinal cord.
abstract: The existence of multipotent progenitor populations in the adult forebrain has been widely studied. To extend this knowledge to the adult spinal cord we have examined the proliferation, distribution, and phenotypic fate of dividing cells in the adult rat spinal cord. Bromodeoxyuridine (BrdU) was used to label dividing cells in 13- to 14-week-old, intact Fischer rats. Single daily injections of BrdU were administered over a 12 d period. Animals were killed either 1 d or 4 weeks after the last injection of BrdU. We observed frequent cell division throughout the adult rodent spinal cord, particularly in white matter tracts (5-7% of all nuclei). The majority of BrdU-labeled cells colocalized with markers of immature glial cells. At 4 weeks, 10% of dividing cells expressed mature astrocyte and oligodendroglial markers. These data predict that 0.75% of all astrocytes and 0.82% of all oligodendrocytes are derived from a dividing population over a 4 week period. To determine the migratory nature of dividing cells, a single BrdU injection was given to animals that were killed 1 hr after the injection. In these tissues, the distribution and incidence of BrdU labeling matched those of the 4 week post injection (pi) groups, suggesting that proliferating cells divide in situ rather than migrate from the ependymal zone. These data suggest a higher level of cellular plasticity for the intact spinal cord than has previously been observed and that glial progenitors exist in the outer circumference of the spinal cord that can give rise to both astrocytes and oligodendrocytes.
authors.affiliation: The Salk Institute for Biological Studies, Laboratory of Genetics, La Jolla, California 92037, USA. fgage@salk.edu
authors.forename: P J
authors.initials: PJ
authors.lastname: Horner
authors.forename: A E
authors.initials: AE
authors.lastname: Power
authors.forename: G
authors.initials: G
authors.lastname: Kempermann
authors.forename: H G
authors.initials: HG
authors.lastname: Kuhn
authors.forename: T D
authors.initials: TD
authors.lastname: Palmer
authors.forename: J
authors.initials: J
authors.lastname: Winkler
authors.forename: L J
authors.initials: LJ
authors.lastname: Thal
authors.forename: F H
authors.initials: FH
authors.lastname: Gage
mesh_terms: D000367:Age Factors; D000818:Animals; D000963:Antimetabolites / Q000032:analysis / Q000493:pharmacokinetics; D001253:Astrocytes / Q000737:chemistry / Q000166:cytology*; D015415:Biomarkers; D001973:Bromodeoxyuridine / Q000032:analysis / Q000493:pharmacokinetics; D002454:Cell Differentiation / Q000502:physiology; D002455:Cell Division / Q000502:physiology; D002465:Cell Movement / Q000502:physiology; D002467:Cell Nucleus; D029721:Drosophila Proteins; D008297:Male; D018613:Microscopy, Confocal; D009474:Neurons / Q000737:chemistry / Q000166:cytology*; D009836:Oligodendroglia / Q000737:chemistry / Q000166:cytology; D051381:Rats; D011916:Rats, Inbred F344; D012471:Salivary Proteins and Peptides / Q000032:analysis; D013116:Spinal Cord / Q000166:cytology* / Q000254:growth & development; D013234:Stem Cells / Q000737:chemistry / Q000166:cytology*
chemical_list: D000963:Antimetabolites; D015415:Biomarkers; D029721:Drosophila Proteins; D012471:Salivary Proteins and Peptides; C081603:ng2 protein, Drosophila; D001973:Bromodeoxyuridine