Laser phototherapy and in vitro release of fibroblast growth factors

Objectives: Phototherapy with low-power laser is able to stimulate wound healing, a process dependent on the interaction of epithelium and connective tissue influencing cellular proliferation and migration. Growth factors are directly involved in these mechanisms. The aim of this study was to analyze the effects of phototherapy using visible red and infrared lasers on secretion of fibroblast growth factors by human gingival fibroblasts in vitro. Methods: Fibroblasts from a primary culture were irradiated twice (6h-interval), with continuous diode laser (GaAlAs- 780nm or InGaAlP- 660nm) in punctual and contact mode, 40mW, spot size of 0.042cm², 3 and 5J/cm² (3s and 5s, respectively). The positive (10% FBS) and negative (1% FBS) controls were not irradiated. The production of keratinocyte growth factor (KGF) and basic fibroblast growth factor (bFGF) was quantified by ELISA. The data were statistically compared by ANOVA followed by the Tukey's test (p≤0.05). Results: The characterization of the cell line indicated a mesenchymal nature. The KGF release was similar in all groups. The bFGF was significantly higher (1.49-fold) in groups treated with infrared laser than positive control. Conclusions: Based on the conditions of this study, we concluded that although phototherapy with low power laser has no influence on KGF production; there is an important positive effect on bFGF production depending on the laser parameters used. The laser phototherapy could be of importance for wound healing, once infrared laser (3 and 5J/cm²) has positive effect on bFGF production.