View article

Low level laser therapy (LLLT) has been shown to stimulate bone cell metabolism but their impact on the matrix metalloproteinase (MMP) expression and activity is little explored. This study evaluated the influence of LLLT at two different wavelengths, red and infrared, on MC3T3-E1 preosteoblast viability, alkaline phosphatase (ALP) and MMP-2 and -9 activities. To accomplish this, MC3T3-E1 cells were irradiated with a punctual application of either red (660 nm; InGaAIP active medium) or infrared (780 nm; GaAlAs active medium) lasers both at a potency of 20 mW, energy dose of 0.08 or 0.16 J, and energy density of 1.9 J/cm² or 3.8 J/cm², respectively. The control group received no irradiation. Cellular viability, ALP and MMP-2 and -9 activities were assessed by MTT assay, enzymatic activity and zymography, respectively, at 24, 48 and 72 h. The treatment of cells with both red and infrared lasers significantly …