Gene expression analysis of acutely traumatized pulps.
BACKGROUND
Vertical root fracture of vital teeth is a relatively rare occurrence. To address early molecular biologic events that take place in the pulp of such cases, we measured mRNA expression levels of selected molecules related to nociception, bacterial pattern recognition, and hard tissue repair/mineralization.


METHODS
Three extracted roots obtained from vital molars diagnosed as vertical root fracture were used. The samples were first analyzed with light and transmission electron microscopy. Then mRNA expression in the apical (root fractured) and coronal portions of the pulp was analyzed by using reverse transcription-polymerase chain reaction (PCR) or real-time PCR after laser capture microdissection.


RESULTS
In all the samples, cracks and vital pulp tissue, but not signs of infection and inflammation, were recognized in the apical portion of the fractured root. The gene expression analysis showed that mRNAs of pattern recognition receptors (CD14, Toll-like receptor 2, and Toll-like receptor 4) and neurokinin-1 receptor were equally expressed in both regions of the pulp. On the other hand, mRNA expression levels of hard tissue-associated proteins (osteopontin, osteonectin, and osteocalcin) and calcium channel voltage-dependent alpha 2 delta subunit 1 (CACNA2D1) in the apical portion of the pulp tissue and periodontal ligaments were significantly up-regulated, as compared with those in the coronal portion of the pulp.


CONCLUSIONS
In the traumatized apical pulp of vertically root-fractured vital teeth, elevated mRNA expression of CACNA2D1, a nociception-related molecule, and proteins related to hard tissue repair/mineralization occurs under noninfectious condition.
Kaneko
Tomoatsu
T
Department of Pulp Biology and Endodontics, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan. tomoendo@tmd.ac.jp
Okiji
Takashi
T
Kaneko
Reika
R
Sunakawa
Mitsuhiro
M
Kaneko
Mitsuhiro
M
Suda
Hideaki
H
D015220:Calcium Channels / Q000096:biosynthesis / Q000235:genetics; D003782:Dental Pulp / Q000293:injuries* / Q000378:metabolism; D020869:Gene Expression Profiling; D006801:Humans; D046529:Microscopy, Electron, Transmission; D015675:Osteocalcin / Q000096:biosynthesis / Q000235:genetics; D015676:Osteonectin / Q000096:biosynthesis / Q000235:genetics; D053495:Osteopontin / Q000096:biosynthesis / Q000235:genetics; D012333:RNA, Messenger / Q000032:analysis; D012038:Regeneration / Q000235:genetics* / Q000502:physiology; D014082:Tooth Fractures / Q000235:genetics*; D014092:Tooth Root / Q000293:injuries*; D014098:Toothache / Q000235:genetics* / Q000378:metabolism; D015854:Up-Regulation
C425903:CACNA2D1 protein, human; D015220:Calcium Channels; D015676:Osteonectin; D012333:RNA, Messenger; D015675:Osteocalcin; D053495:Osteopontin