Effect of Low-Level Laser Irradiation on IGF-II and IGFBP-2 Gene Expressions in Osteoblasts

Abstract

A number of studies have attempted to elucidate the biostimulatory effects of bone formation by low-level laser irradiation (LLLI) ; however, the molecular basis of the mechanism remains obscure. The administration of IGF-II/IGFBP-2 prevents the loss of bone mineral density in osteoporosis and stimulated bone formation. In the present study, to elucidate the mechanism of LLLI on bone formation, osteoblast-like cells MC3T3-E1 established from mouse calvaria cells were irradiated with LLLI and the IGF-II and IGFBP-2 mRNA gene expression levels were analyzed. Reverse transcription-polymerase chain reaction (RT-PCR) demonstrated that IGF-II and IGFBP-2 mRNA levels were increased by LLLI. The quantitative analysis of increased mRNA level was also confirmed by real-time PCR. These findings suggest that the increased IGF-II and IGFBP-2 gene expressions by LLLI in osteoblastic cells may be involved in the stimulation of bone formation.