Isolation and partial sequencing of cDNA clones from rat incisor after Nd:YAG laser irradiation in root canal

SummaryObjectiveThe purpose of this study was to identify the genes expressed in odontoblast-like cells and related to osteodentin production of pulp cells in vivo during the repair process.MethodsA pulsed Nd:YAG laser was irradiated in mandibular incisors of rats at 2 W and 20 pulses/s for 5 s. We constructed a unidirectional cDNA library from the non-calcified portion of irradiated incisors, sequenced cDNA clones and classified their sequences by homology search through the GenBank database.ResultsOf the sequences determined, 26% represented sequences of new genes that were not related to any previously reported gene. 65.5% of the clones strongly matched genes and proteins in the databases. Among them, sequences found more than once were amelogenin, ameloblastin, amelin, collagen α1 type 1, osteonectin, nestin, enamelin and osteocalcin. Sequences detected only once were transforming growth factor beta-1 (TGF-β1), growth hormone receptor (Ghr), glypican, enamelysin (Mmp20), amelin 2, integral membrane protein 2B, amelogenin precursor (Ame1), splicing factor 3b, insuline-like growth factor binding protein 5.ConclusionThis library reflects the gene expression during the dentin repair process in vivo including the odontoblast-like cell specific gene expression and osteodentin-production. Using this library, we indicate the candidate genes which might be related to odontoblast-differentiation and formation of osteodentin.