Effects of low-power laser irradiation on the bone formation by the rat osteoblast

Abstract

Low-power laser irradiation provides healing acceleration, and is supposed to accelerate for bone formation after fracture. However, the mechanism of laser healing is not well known. In the present study, we investigated the effects of laser irradiation on the osteoblastic bone formation. When osteoblastic cells from 3-days-old rat calvaria were irradiated in a variety of condition. The greatest bone formation was observed by the laser irradiation at the first week after seeding and in irradiation energy of 3.75 J/cm². The laser irradiation induced the increase of ALP activity at 7 days after seeding, and the increased number of cells at 4 days and after. These results suggest that cell proliferation was enhanced by laser irradiation in the early stage of culture, and the increased number of cells and stimulated osteoblast differentiation results in the increase of bone formation.