The Pulsed Nd:YAG Laser Therapy Enhanced Nerve Regeneration via Apoptosis Inhibition in a Rat Crushed Sciatic Nerve Model.

ABSTRACT

The study was aimed to validate the efficacy of the pulsed NdYAG laser on nerve regeneration in a rat sciatic nerve crushed model. 54 Wistar rats were randomly assigned into three groups shame control, crush control, and laser treated group. For the laser treated group, the pulsed NdYAG laser (10 Hz) with 350 mJ per pulse in energy density and 50 J/cm2 in fluence was applied extracorporeally at the lesion site for 12 min to daily deliver 500 J immediately and consecutive 9 days following the crush injury. At week 1, the apoptosis-related activities in the injured nerve were examined (n = 8/each group). The sciatic functional index (SFI) was measured preoperatively and weekly until 4 weeks after the index procedure. The injured nerve and the innervated gastrocnemius muscle histology were assessed at week 4 (n = 10/each group). At week 1, the laser group showed the significant less TUNEL-positive ratio (P < 0.05), and the lower expression of cleaved caspase3/procaspase-3 and beclin-2/beclin-2-associated protein X ratios compared with the crush control. Furthermore, the laser group revealed significantly better SFI since week 1 and throughout the study (P < 0.05, all) compared with the crush control. At week 4, the laser group showed significantly higher axon density, lower myelin g-ratio, and the corresponding higher glycogen expression (P < 0.05, all) in the gastrocnemius muscle compared with those in the crush control. The pulsed NdYAG might enhance the injured nerve regeneration via apoptosis inhibition.