Abstract
Recently, much attention has been paid to the analgesic and anti-inflammatory effects of low power laser irradiation.However,the mechanism remains unclear. In the present study, we have performed experiments of in vitro laser irradiation on cultured synovial cells from patients with RA in order to investigate the effect on DNA synthesis.
Cultured synovial cells were prepared from synovial tissue obtained during knee joint surgery from six patients with RA. A continuous wave He-Ne laser was irradiated on the cells, with a wave length of 632. 8 nm and a power output of 8.5 mW±20% (11.5 mW measured). Following the irradiation at energy densities varying from 5 to 2000 mJ/cm2, DNA syntheses of irradiated cells were measured by 3H-thymidine incorporation.
In all six cases,DNA synthesis was significantly inhibited,but each of the cultures showed a different inhibitory response to the irradiation.Morphological observation by a phase-contrast microscope revealed no destructive change by heat energy of laser irradiation.
Thus, the results suggest that, under the conditions in this experiment,low power He-Ne laser has a direct effect on cultured synovial cells from patients with RA, and inhibits aberrant cell proliferation through a certain non-thermal action mechanism.
