Infrared low-level diode laser on serum chemokine MCP-1 modulation in mice

The effect of the low-level laser therapy (LLLT) in the modulation of cells related to inflammatory processes has been widely studied, with different parameters. The objective was to investigate the immediate and cumulative effect of infrared LLLT on chemokine monocyte chemotactic protein-1 (MCP-1) modulation in mice. Fifty-two isogenic mice were distributed in seven groups: control (n = 10, no surgical procedure), laser I (n = 7, surgical procedure and a single LLLT exposure 12 h after the surgery), laser II (n = 7, surgery followed by two LLLT exposures, 12 and 36 h after surgery), and laser III (n = 7, surgery followed by three LLLT exposures, 12, 36, and 60 h after surgery). For each group, a sham group (n = 21) underwent surgery without laser application. The animals in the laser groups received an infrared diode continuous laser exposure (AsGaAl, 780 nm wavelength, power of 20 mW, energy density of 10 J/cm(2), spot size of 0,04 cm(2)) on three points (20 s per point), and a final energy of 0.4 J. The animals were sacrificed 36 h (laser I and sham I groups), 60 h (laser II and sham II), and 84 h (laser III and sham III groups) after surgery. The MCP-1 concentrations were measured by cytometric bead array. There was no significant difference between the three periods in the sham group (p = 0.3). There was a lower concentration of MCP-1 in the laser III group compared to the laser I group (p = 0.05). The infrared LLLT showed a cumulative effect in the modulation of chemokine MCP-1 concentration. Three LLLT exposures were necessary to achieve the MCP-1 modulation.