Effects of low power laser irradiation on olfactory ensheathing cells in vitro / 中华物理医学与康复杂志

ABSTRACT

Objective To investigate the effects of 810 nm semi-conductor laser irradiation on the proliferation of olfactory ensheathing cells in vitro. Methods Olfactory ensheathing cells obtained from adult rat olfactory mucosa using the method based on different rates of attachment were irradiated with a semi-conductor laser ( wave length 810 nm; power density 10.3 mW/cm2) for 30, 60 or 120 seconds. Laser irradiation was performed 3 times with a 24 h interval. After the last irradiation, the cells were cultured. At the 3rd, 5th and 8th day of cell culture,cell proliferation was assessed with cell counts and a methylthiazoletetrazolium ( MTT) colorometric method. Results After 3 days of cell culture, the number of cells and average MTT values showed no statistically significant difference between the irradiated and control groups. At the Sth and 8th day, the differences among all the laser exposure groups and with the control group were significant, except for the average MTT values of the control group and the 30 s exposure group. Maximal effect was achieved with a 60 s exposure. Conclusions Low power laser irradiation can stimulate the proliferation of olfactory ensheathing cells in vitro, and the effect is time-dose dependent. The optimal irradiation time was found to be 60 s daily for 3 times, with a 24 h interval.