title: Mapping of BrdU label-retaining dental pulp cells in growing teeth and their regenerative capacity after injuries.
abstract: Recent studies have demonstrated that human dental pulp contains adult stem cells. A pulse of the thymidine analog BrdU given to young animals at the optimal time could clarify where slow-cycling long-term label-retaining cells (LRCs), putative adult stem cells, reside in the pulp tissue. This study focuses on the mapping of LRCs in growing teeth and their regenerative capacity after tooth injuries. Two to seven peritoneal injections of BrdU into pregnant Wistar rats revealed slow-cycling long-term dense LRCs in the mature tissues of born animals. Numerous dense LRCs were postnatally decreased in number and reached a plateau at 4 weeks after birth when they mainly resided in the center of the dental pulp, associating with blood vessels. Mature dental pulp cells were stained with Hoechst 33342 and sorted into (<0.76%) side population cells using FACS, which included dense LRCs. Some dense LRCs co-expressed mesenchymal stem cell markers such as STRO-1 or CD146. Tooth injuries caused degeneration of the odontoblast layer, and newly differentiated odontoblast-like cells contained LRCs. Thus, dense LRCs in mature pulp tissues were supposed to be dental pulp stem cells possessing regenerative capacity for forming newly differentiated odontoblast-like cells. The present study proposes the new hypothesis that both granular and dense LRCs are equipped in the dental pulp and that the dense LRCs with proliferative capacity play crucial roles in the pulpal healing process following exogenous stimuli in cooperation with the granular LRCs.
authors.affiliation: Division of Anatomy and Cell Biology of the Hard Tissue, Department of Tissue Regeneration and Reconstruction, Niigata University Graduate School of Medical and Dental Sciences, 2-5274 Gakkocho-dori, Chuo-ku, Niigata 951-8514, Japan.
authors.forename: Yuko
authors.initials: Y
authors.lastname: Ishikawa
authors.forename: Hiroko
authors.initials: H
authors.lastname: Ida-Yonemochi
authors.forename: Hironobu
authors.initials: H
authors.lastname: Suzuki
authors.forename: Kuniko
authors.initials: K
authors.lastname: Nakakura-Ohshima
authors.forename: Han-Sung
authors.initials: HS
authors.lastname: Jung
authors.forename: Masaki J
authors.initials: MJ
authors.lastname: Honda
authors.forename: Yumiko
authors.initials: Y
authors.lastname: Ishii
authors.forename: Nobukazu
authors.initials: N
authors.lastname: Watanabe
authors.forename: Hayato
authors.initials: H
authors.lastname: Ohshima
mesh_terms: D053687:Adult Stem Cells / Q000502:physiology*; D000818:Animals; D001973:Bromodeoxyuridine; D002454:Cell Differentiation; D049109:Cell Proliferation; D003737:Dental Cavity Preparation; D003782:Dental Pulp / Q000166:cytology* / Q000502:physiology; D005260:Female; D059630:Mesenchymal Stem Cells / Q000166:cytology*; D011247:Pregnancy; D051381:Rats; D017208:Rats, Wistar; D012038:Regeneration; D058985:Side-Population Cells / Q000166:cytology; D018677:Tooth Injuries / Q000503:physiopathology; D014090:Tooth Replantation
chemical_list: D001973:Bromodeoxyuridine