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Temporospatial localization of dentine matrix protein 1 following direct pulp capping with calcium hydroxide in rat molars
Author(s) -
Shigetani Y.,
Yoshiba K.,
Kuratate M.,
Takei E.,
Yoshiba N.,
Yamanaka Y.,
Ohshima H.,
Okiji T.
Publication year - 2015
Publication title -
international endodontic journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.988
H-Index - 119
eISSN - 1365-2591
pISSN - 0143-2885
DOI - 10.1111/iej.12351
Subject(s) - dmp1 , odontoblast , nestin , osteopontin , pulp capping , pulp (tooth) , chemistry , molar , calcium hydroxide , pathology , anatomy , microbiology and biotechnology , biology , viral matrix protein , dentistry , medicine , biochemistry , endocrinology , stem cell , neural stem cell , gene
Aim To examine the temporospatial expression of dentine matrix protein 1 ( DMP 1; a noncollagenous protein involved in mineralized tissue formation), osteopontin (another noncollagenous protein detected during reparative dentinogenesis) and nestin (a marker of differentiating/differentiated odontoblasts), following direct pulp capping with calcium hydroxide in rat molars. Methodology The maxillary first molars of 8‐week‐old Wistar rats had their pulps exposed and capped with calcium hydroxide. The pulp‐capped teeth were collected from 6 h to 14 days postoperatively and processed for immunohistochemistry for DMP 1, osteopontin and nestin. Cell proliferation was monitored using 5‐bromo‐2′‐deoxyuridine (BrdU) labelling. Results The capped pulps initially exhibited superficial necrotic changes followed by the formation of new matrix and its mineralization. DMP 1 immunoreactivity was observed in the matrix beneath the necrotic layer from 6 h onwards and present in the outer portion of the newly formed mineralized matrix from 7 days onwards. Osteopontin displayed a similar expression pattern, although it occupied a narrower area than DMP 1 at 6 and 12 h. Nestin‐immunoreactive cells appeared beneath the DMP 1‐immunoreactive area at 1 day, were distributed beneath the newly formed matrix at 5 days and exhibited odontoblast‐like morphology by 14 days. BrdU‐positive cells significantly increased at 2 and 3 days ( P < 0.05) and then decreased. Conclusions The deposition of DMP 1 at exposed pulp sites preceded the appearance of nestin‐immunoreactive cells, active cell proliferation and new matrix formation after pulp capping with calcium hydroxide in rat molars, suggesting that DMP 1 acts as a trigger of pulp repair. The colocalization of DMP 1 and osteopontin suggests that these two proteins play complementary roles.