Biomodulation of Inflammatory Cytokines Related to Oral Mucositis by Low-Level Laser Therapy

This study evaluated the effects of LLLT on the expression of inflammatory cytokines related to the development of oral mucositis by gingival fibroblasts. Primary gingival fibroblasts were seeded on 24-well plates (10(5) cells/well) for 24h. Fresh serum-free culture medium (DMEM) was then added, and cells were placed in contact with LPS (Escherichia coli, 1gmL(-1)), followed by LLLT irradiation (LaserTABLEInGaAsP diode prototype780nm, 25mW) delivering 0, 0.5, 1.5 or 3Jcm(-2). Cells without contact with LPS were also irradiated with the same energy densities. Gene expression of TNF-, IL-1, IL-6 and IL-8 was evaluated by Real-Time PCR, and protein synthesis of these cytokines was determined by enzyme-linked immunosorbent (ELISA) assay. Data were statistically analyzed by the Kruskal-Wallis test, complemented by the Mann-Whitney test (P<0.05). LPS treatment increased the gene expression and protein synthesis of TNF-, IL-6 and IL-8, while the expression of IL-1 was not affected. For LPS-treated groups, LLLT promoted significant decreases in the expression of TNF-, IL-6, and IL-8 at 1.5Jcm(-2) and 3Jcm(-2). These results demonstrate that LLLT promoted a beneficial biomodulatory effect on the expression of inflammatory cytokines related to oral mucositis by human gingival fibroblasts. (AU)