Modulating nitric oxide levels in dorsal root ganglion neurons of rat with low-level laser therapy

Nitric oxide （NO） and nitric oxide synthase （NOS） have an important role in pain signaling transmission in animal models. Low-level laser therapy （LLLT） is known to have an analgesic effect, but the mechanism is unclear. The aim of the study is to investigate the influence of LLLT on NO release and NOS synthesis in dorsal root ganglion （DRG） neurons, in order to find whether LLLI can ameliorate pain through modulating NO production at the cellular level. The results show that in stress con- ditions, the laser irradiation at 658 nm can modulate NO production in DRG neurons with soma diameter of about 20 μm in a short time after illumination, and affect NOS synthesis in a dose-dependent manner. It is demonstrated that LLLT might treat pain by altering NO release directly and indirectly in DRG neurons.