RESUMO
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 immunohistochemistry 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.