The Effect on Fos Expression in Rat Spinal Cord following Stimulation to Dorsal Root Ganglion by Pulsed Radiofrequency

Objective: To reconfirm the relationship between the Fos expression and the pulsed radiofrequency which very few articles have reported. Method: Thirty-four male Sprague-Dawely rats were enrolled: 8 for lumbar 3rd dorsal root ganglion (DRG) stimulation, 4 for L3 and L4 DRGs, 5 for C5 and C6 DRGs, 8 for sham L3 DRGs, 5 for sham L3 and L4 DRGs, and 4 for sham C5 and C6 DRGs. Without laminectomy, each lumbar DRG was stimulated with PRF for 2 minutes 2 times with 42 degrees C. Sham group was stimulated with PRF electrode but without any stimulation. Three hours after the stimulations, spinal cord was thin sectioned for immunohistoche-mistry and Fos expression was calculated. Individual sections were digitized with 4096 gray levels using a computer assisted image analysis system. With laminectomy, cervical DRGs was stimulated with the same method of lumbar DRGs. Sham stimulation was applied to the sham group. Results: No significant difference of Fos expression was observed on dorsal horn of rat in operated site, 3 hours later after operation, between the PRF and sham group in lumbar DRGs and the PRF and sham groups in cervical DRGs. Conclusion: The expression of Fos was not significantly related with the cervical and the lumbar DRGs stimulation with PRF.