Open AccessLocalization of Metallothionein (MT) and Expression of MT Isoforms Induced by Cadmium in Rat Dental Pulp
Author(s) -
Chiharu Sogawa,
Norio Sogawa,
Tetsuro Yamamoto,
Nariaki Oda,
Tetsuyoshi Inoue,
Kenji Onodera,
Hiroaki Furuta
Publication year - 2001
Publication title -
japanese journal of pharmacology/japanese journal of pharmacology
Language(s) - English
Resource type - Journals
eISSN - 1347-3506
pISSN - 0021-5198
DOI - 10.1254/jjp.86.65
Subject(s) - odontoblast , metallothionein , microbiology and biotechnology , messenger rna , pulp (tooth) , gene isoform , immunohistochemistry , western blot , chemistry , cadmium , biology , pathology , biochemistry , immunology , gene , medicine , organic chemistry
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.