Effect of Low - Level Helium - Neon Laser Irradiation on Proliferation Rate of Cultured Human Fibroblasts in High Glucose Medium

This study aimed to evaluate the effects of low level laser on human fibroblasts which were cultured in high glucose cultures. The human skin fibroblasts were maintained in Dulbecco's Modified Eagle's Medium (DMEM) in a humidified air-5% CO2 atmosphere. The cells were cultured. Irradiation was carried out with Helium-Neon (He-Ne) laser unit with power output of 1.5 mW and the diameter of irradiating beam of 1.7 cm on the case groups. In the next step the cells were cultured in high glucose culture medium (15mM/L) for one week before laser irradiation. The irradiation was carried out with the same laser unit with power output of 1.5 mW and the diameter of irradiating beam of 1.7 cm on the case groups. Control cells did not receive laser. The cells were irradiated with three doses of 0.5, 1 and 2 J/cm2 on three consecutive days. Cell proliferation was evaluated by dimethylthiazol-diphenyltetrazolium bromide (MTT) assay. Data were analyzed by student t test or Mann-Whitney-U test. Laser treatments of 0.5 (p-value=0.002) and 1 (p-value=0.046) had a stimulatory effect and three irradiations of 2 J/cm2 had a negative effect (p-value=-0.011) on proliferation rate of fibroblasts which were cultured in normal culture medium compared to non irradiated cells. All three doses of 0.5 (p-value=0.042), 1 (p-value≈0.00) and 2 J/cm2 (p-value≈0.00) had a stimulatory effect on proliferation rate of fibroblasts which were cultured in culture medium with high glucose concentration (15mM/L) in comparison with hyper glycemic non irradiated cells. Low level laser irradiation with helium-neon unit on cultured human fibroblasts in normal and high glucose mediums increased their growth and proliferation.