Ultrasound Therapy of Injury Site Modulates Gene and Protein Expressions in the Dorsal Root Ganglion in a Sciatic Nerve Crush Injury Rat Model

The aim of this study was to verify the effects of ultrasound on dorsal root ganglion (DRG) neurons at the injury site in a rat model of sciatic nerve crush injury. We evaluated the mRNA expression of neurotrophic and pro-inflammatory factors by quantitative reverse transcription polymerase chain reaction 7 and 14 d post-injury. We also evaluated the protein levels of brain-derived neurotrophic factor (BDNF) 7 and 14 d post-injury. Axon regeneration and motor function analyses were performed 21 days after injury to confirm the facilitative effect of ultrasound on nerve regeneration. In the ultrasound group, BDNF and interleukin-6 mRNA expression of the DRG was significantly reduced 7 d post-injury. Compared with the sham group, the BDNF protein expression of the DRG in the ultrasound group remained at a higher level 14 d post-injury. Motor function, myelinated fiber density and myelin sheath thickness were significantly higher in the ultrasound group than in the sham group 21 d post-injury. These results indicate that ultrasound therapy at the injury site promotes nerve regeneration and modulates gene and protein expression in the DRG of a rat model of a sciatic nerve crush injury.