The relationship between the cusp pattern and plural stem cell compartments in Guinea pig cheek teeth by chasing BrdU-labeling.
Continuously growing rodent incisors have a special epithelial structure for maintaining adult stem cells that shows a bulbous epithelial protrusion at the apical end and is referred to as an "apical bud". Guinea pig cheek teeth (premolars and molars), also continuously growing teeth, have a complex crown shape consisting of plural cusps. The present study clarifies the existence of apical buds in guinea pig premolars/molars as it examines the relationship between the crown shape and the orientation of the apical buds by micro-computed tomography (micro-CT) and immunohistochemistry for 5-bromo-2'-deoxyuridine (BrdU). One premolar and three molar teeth in each side of the maxillae and mandibles assumed characteristic features: each horizontally-sectioned tooth showing a complex zigzag shape was composed of a core of dentin covered by a layer of enamel on all axial surfaces except the buccal of the uppers and the lingual of the lowers. Furthermore, four bulbous epithelial protrusions--including the stellate reticulum--were recognized in the apical end of each tooth, where slow-cycling long-term label-retaining cells resided 20 days after a peritoneal injection of BrdU. These data indicate that guinea pig premolars/molars have four apical buds where the epithelial adult stem cells reside. In contrast, rodent incisors, which show a single cone appearance, are covered by enamel on the labial side and possess only one apical bud. The results of this study suggest that plural apical buds, being arranged bucco-lingually and mesio-distally, produce the crown mold in a zigzag fashion.
Hashimoto
Emi
E
Department of Tissue Regeneration and Reconstruction, Niigata University Graduate School of Medical and Dental Sciences, and Pediatric Dentistry, Niigata University Medical and Dental Hospital, Niigata, Japan.
Nakakura-Ohshima
Kuniko
K
Kenmotsu
Shin-ichi
S
Suzuki
Hironobu
H
Nakasone
Naohiro
N
Saito
Chikara
C
Harada
Hidemitsu
H
Ohshima
Hayato
H
D000818:Animals; D001973:Bromodeoxyuridine / Q000378:metabolism*; D002610:Cheek / Q000033:anatomy & histology*; D003481:Cuspid / Q000033:anatomy & histology / Q000166:cytology* / Q000000981:diagnostic imaging / Q000254:growth & development; D004847:Epithelial Cells / Q000166:cytology; D006168:Guinea Pigs; D007700:Kinetics; D013194:Staining and Labeling; D013234:Stem Cells / Q000166:cytology*; D055114:X-Ray Microtomography; D014965:X-Rays
D001973:Bromodeoxyuridine