820 Nm Gallium Aluminum Arsenide Laser Modulation of Prostaglandin E2 Production in Interleukin I Stimulated Myoblasts

Abstract

A number of clinical studies have reported the efficacy of the 820 nm Gallium Aluminum Arsenide (GaAlAs) laser for the management of musculoskeletal pain, but its mode of action is not clear. The aim of this study was to investigate the effect of 820 nm GaAlAs at energy densities of 4 J/cm2 and 19 J/cm2 on prostaglandin E2 (PGE2) production by myoblast cultures undergoing stimulation with interleukin I alpha (IL-1). The differentiated C2C12 cultures were allocated randomly into 6 groups (6 samples per group). Each group, except the control and the IL-1 supplement groups, was irradiated with 820 nm GaAlAs at energy densities of 4 J/cm2 or 19 J/cm2 on three occasions. The irradiation was undertaken initially and at one hour and two hours. The difference in mean PGE2 at 12 hours among the 6 groups was statistically significantly different as compared by Analysis of Variance, p=0.0001. The result from Scheffe multiple comparison (p = 0.05) showed that the PGE2 production of the culture with IL-1 and the culture with IL-1 irradiated by 820 nm at 4 J/cm2 were higher than the control group. There was no statistically significant difference in PGE2 production among the control group, the laser-irradiated groups without IL-1 supplement and the IL-1 stimulation group irradiated by 820 nm at 19 J/cm2. The results indicate that IL-1 can stimulate PGE2 synthesis in differentiated C2C12 skeletal muscle cells. 820 nm laser irradiation at 19 J/cm2 was found to inhibit that mechanism, while the lower energy density (4 J/cm2) failed to inhibit PGE2 production. © 1999, International Phototherapy Association. All rights reserved.