title: Localization of metallothionein (MT) and expression of MT isoforms induced by cadmium in rat dental pulp.
abstract: We investigated the induction of metallothionein (MT) by cadmium (Cd) in the dental pulp of rat incisors. Time-course studies of MT mRNA expression after single Cd injection were observed by Northern-blot analysis. The isoform-specific expressions of MT mRNAs (MT-I, MT-II and MT-III) were observed using the reverse transcriptase-polymerase chain reaction (RT-PCR) method. Both MT-I and MT-II mRNA levels increased within 3 h, peaked at 3 h and then decreased. These findings demonstrated that MT-I and MT-II mRNA were rapidly induced by Cd in dental pulp. MT-III mRNA was constitutively expressed in rat dental pulp, but the expression level did not change by Cd treatment. The localization of MT protein in Cd-treated rat dental pulp was determined by immunohistochemical staining using anti-MT antibody against MT-I and MT-II. MT protein was localized in the specific cell type of odontoblasts (secretory odontoblasts and resting odontoblasts). In conclusion, it is likely that stained MT in the immunohistochemical study should be MT-I and/or MT-II. Furthermore, MT-I and/or MT-II in Cd-treated rat dental pulp was localized in odontoblasts, in which accumulation of Cd were reported. The cell-specific synthesis of MT may be associated with its metal storage and detoxification role in dental tissues.
authors: Department of Dental Pharmacology, Okayama University Dental School, Japan. caoki@md.okayama-u.ac.jp
authors: C A
authors: CA
authors: Sogawa
authors: N
authors: N
authors: Sogawa
authors: T
authors: T
authors: Yamamoto
authors: N
authors: N
authors: Oda
authors: T
authors: T
authors: Inoue
authors: K
authors: K
authors: Onodera
authors: H
authors: H
authors: Furuta
mesh_terms: D000818:Animals; D015152:Blotting, Northern; D002104:Cadmium / Q000494:pharmacology*; D003782:Dental Pulp / Q000187:drug effects / Q000378:metabolism*; D007150:Immunohistochemistry; D007536:Isomerism; D008297:Male; D008668:Metallothionein / Q000096:biosynthesis / Q000378:metabolism*; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors
chemical_list: D012333:RNA, Messenger; D002104:Cadmium; D008668:Metallothionein