Abstract
The recent advent of improved low-level laser irradiation (LLLI) therapy has promoted interest in clinical implantology. It has been reported that LLLI on bony implant sites might have positive effects on the integration of implants. The biostimulatory effect of cell proliferation and bone formation by LLLI has been investigated, but little is known about the molecular basis of biostimulatory mechanisms. Since LLLI will be useful to support implant therapy, it is important to elucidate the mechanism of the biostimulatory effect of LLLI on bone formation.
We previously constructed the cDNA library of mouse osteoblastic cells (MC 3 T 3-E 1), which enhanced gene expression by LLLI using a subtracted gene cloning technology. In the present study, we further analyzed the DNA nucleotide sequence of gene clones, and focused on a gene clone designated MCL-174. The nucleotide sequence of MCL-174 insert was determined and assessed in the standard nucleotide-nucleotide BLAST (blastn) homology-search using NCBI DNA databases. DNA nucleotide sequences of clone MCL-174 inserted DNA exhibited 99% homology with Mus musculus annexin Ⅲ gene. Reverse-transcription PCR analysis showed that the mRNA level was enhanced by LLLI. These findings suggest that LLLI may enhance mRNA transcription and play a role in stimulating proliferation of osteoblasts through the enhancement of annexin Ⅲ gene expression. Annexin Ⅲ was detected in secretory ameloblasts and odontoblasts, and it was thought to be involved in the regulation of cell calcium. These findings suggest that the biostimulatory effect of LLLI on bone formation may relate through gene expression of annexin Ⅲ.
