LLLT Effects on He-Ne Lased Bone-marrow Cells Cultured on Titanium Plates

Abstract

The low level laser therapy (LLLT) effects of He-Ne laser irradiation on cultured bone-marrow-derived cells have not been well investigated. The objective of this study was to examine the LLLT effects of He-Ne laser irradiation on cell reaction of bone-marrow cells with a view to applying these effects in clinical settings. Femur-derived bone-marrow cells were obtained from Sprague-Dawley rats. He-Ne lased (1.20 J/cm²) cells in the second passage were incubated in plastic culture dishes, and the proliferation and differentiation were examined. The proliferation was evaluated by the optical density method, and the expression of alkaline phosphatase (ALP), osteopontin (OPN), and/or osteocalcin (OCN) were analyzed by real-time RT-PCR. ALP activity was also examined using culture area- and colorimetry-based assays. LLLT effects on He-Ne lased bone-marrow cells cultured on titanium plates were also examined in the same way. 1. He-Ne laser irradiation accelerated the strong proliferation and ALP (p<0.05) activity of plastic-cultured-bone-marrow cells compared with the non-irradiated cells. These results demonstrated LLLT effects on the proliferation and differentiation of He-Ne laser irradiated plastic-cultured-bone-marrow cells. 2. He-Ne lased bone-marrow cells cultured on titanium plates exhibited significant proliferation and differentiation activities. Real-time RT-PCR showed strong expression of ALP and OPN (p<0.05). These results also revealed LLLT effects on the proliferation and differentiation of He-Ne laser irradiated titanium-cultured-bone-marrow cells. Under the conditions of this study, He-Ne laser irradiation revealed LLLT effects on bone-marrow cells cultured even on titanium plates. Thus, He-Ne laser irradiation around the bone hole is expected to produce LLLT effects for the fixing of implants.