Abstract
Although it has been reported that low level laser irradiation (LLLI) appears to stimulate bone formation, little is known in detail about its possible role in osteoblast function. The present study examines the effect of LLLI on the function of rat calvarial osteoblast cells (ROB) and rat osteoblast cell lines (ROS 17/2.8) in terms of cell proliferation, alkaline phosphatase (ALP) activity, and calcified nodule formation. To determine the effects of LLLI on the osteoblast cell function, the ROB and ROS 17/2.8 cells were cultured and were treated with LLLI. An unirradiated group served as the control. LLLI irradiated cells demonstrated a slight increase in proliferation and slight decrease in the number of dead cells compared with the control,, but the differences were not statistically significant. LLLI increased the ALP activity in culture of ROBs and ROS 17/2.8 cells with a statistically significant difference (ANOVA and multiple comparison tests) compared with the unirradiated controls (p ‹ 0.0001 in both groups). LLLI irradiated cells also showed a statistically significantly greater increase in bone nodule formation for both ROBs (p = 0.0421) and ROS 17/28 cells (p = 0.0119) using an unpaired t-test. These results offer the possibility that LLLI could promote osteoblast-modulated bone formation by stimulating osteoblast function in addition to bone mineralization.
