Effect of low-power laser therapy in L5 dorsal root ganglion of mice submitted to sciatic nerve crush injury

Abstract

The purpose of this study was to assess the effect of low-power laser therapy (LPLT) on the regenerating peripheral neurons in adult animals. The right sciatic nerve of twelve mice adults was experimentally crushed with a Halstead forceps during 30 seconds. Animals were randomly distributed into three: HeNe, GaAs and NR. HeNe group received radiation laser HeNe (3 J/cm²). The animals of the GaAs group received GaAs laser irradiation (30 mJ) and the remnant animals (NR) were not radiated. The radiation was daily transcutaneously applied to L5 dorsal root ganglion, for 21 days. Other four non-operated animals served as normal controls (NOR). After 21 days, the sciatic nerve was collected and processed for histological assessment and axonal counting. The L5 dorsal root ganglion (DRG) was also removed for morphologic and morphometric evaluation of sensory surviving neurons. No difference was found in the number and size of DRG neurons among the experimental groups. The results indicate that LPLT did not improve regeneration of peripheral nerves in mice. LPLT had no neuroprotective effect on neurons after axonal lesion.