Immunocytochemical detection of dentine matrix protein 1 in experimentally induced reactionary and reparative dentine in rat incisors.
OBJECTIVE
Although the general mechanisms of dentinogenesis are understood, several aspects regarding tertiary dentine formation still deserve investigation, especially regarding the presence and distribution of some noncollagenous matrix proteins. As dentine matrix protein 1 (DMP 1) is present in primary dentine, it is possible that this protein may also be present in the dentine matrix secreted after injury, but there are no immunocytochemical studies attempting its detection in tertiary dentine. The aim of this study was to examine the ultrastructural immunolocalization of DMP 1 in the tertiary dentine after extrusion of the rat incisor.


METHODS
Upper incisors were extruded 3mm and then repositioned into their sockets. After several periods, the incisors were fixed and processed for transmission electron microscopy and for immunocytochemistry for DMP 1.


RESULTS
Extrusion yielded both types of tertiary dentine, which varied in aspect and related cells. DMP 1 was found in the mineralized matrix of all types of dentine, presenting high affinity for collagen, but rare colloidal gold particles over predentine. DMP 1 was evident in the supranuclear region and inside the nucleus of some odontoblast-like cells.


CONCLUSIONS
The observed association between DMP 1 and collagen seem to be essential for reactionary and reparative dentine formation.
Division of Oral Biology, School of Dentistry, University of São Paulo, Av. Prof. Lineu Prestes 2227, Cidade Universitaria, 05508-900 São Paulo, SP, Brazil.
Marcio Cajazeira
MC
Aguiar
Victor E
VE
Arana-Chavez
D000818:Animals; D002467:Cell Nucleus / Q000648:ultrastructure; D003094:Collagen / Q000648:ultrastructure; D003743:Dental Enamel / Q000648:ultrastructure; D003782:Dental Pulp / Q000648:ultrastructure; D003809:Dentin, Secondary / Q000648:ultrastructure*; D016326:Extracellular Matrix Proteins / Q000032:analysis*; D017979:Gold Colloid; D007150:Immunohistochemistry; D007180:Incisor / Q000293:injuries / Q000648:ultrastructure*; D008297:Male; D046529:Microscopy, Electron, Transmission; D009804:Odontoblasts / Q000648:ultrastructure; D010750:Phosphoproteins / Q000032:analysis*; D051381:Rats; D017208:Rats, Wistar; D014084:Tooth Avulsion / Q000473:pathology; D014090:Tooth Replantation
C081635:Dmp1 protein, rat; D016326:Extracellular Matrix Proteins; D017979:Gold Colloid; D010750:Phosphoproteins; D003094:Collagen