Low back pain is a common problem, affecting approximately two-thirds of the adult population. Of these individuals, a significant percentage will exhibit symptoms of radicular pain or sciatica. The purpose of this study was to determine the effect of one systemic (2 mg/kg) or intrathecal (0.2 mg/kg) dose of a selective cyclooxygenase-2 inhibitor (SC-236) in decreasing existing mechanical allodynia in a rat model of radiculopathy. Gait disturbance and mechanical allodynia (increased response to non-noxious von Frey monofilament stimuli) were assessed daily until the rats were killed 7 days after surgery. Robust mechanical allodynia developed in the rats in all groups except for those in the sham group by day 1 after surgery. Mechanical allodynia was significantly lower in the rats that received the systemic or the intrathecal dose of SC-236 than in those in the vehicle control group (analysis of variance followed by Bonferroni multiple comparison test, p = 0.002). The intrathecal drug route of administration produced greater attenuation in allodynia than the systemic dose, supporting a central mechanism of action of the cyclooxygenase-2 inhibitor (p = 0.002). The hypothesis that cyclooxygenase-2 is involved in spinal nociceptive processing after a nerve root injury was supported by this study. In addition, these data support continued basic science research to further elucidate central inflammatory processes that follow nerve root injury.
ASJC Scopus subject areas
- Orthopedics and Sports Medicine