• The Journal of Korean Physical Therapy
• /
• v.21 no.3
• /
• pp.95-102
• /
• 2009

Purpose: This study evaluates MCP-1 expression in the dorsal horn of a rat model of lumbar disc herniation by an autograft of the nucleus pulposus to the spinal nerve. Methods: After a coccygeal nucleus pulposus graft to the left $5^{th}$ lumbar spinal nerve, proximal to dorsal root ganglion, mechanical allodynia and thermal hyperalgesia were assessed 1 day before surgery, and 1, 10, 20, 30 days after surgery. The mRNA of MCP-1 in the dorsal horn was assessed by real time PCR to compare the temporal pattern of neuropathic pain of the lumbar disc herniation model. Results: In the ipsilateral side of the lumbar disc herniation models, mechanical allodynia and thermal hyperalgesia reached a maximum at 10 days after surgery with significant difference from the control group. Pain was also provoked in the contralateral side of the lumbar disc herniation models with less intensity than the ipsilateral side. The level of MCP-1 mRNA expression in the dorsal horn reached a peak at 20 days after surgery. Conclusion: Mechanical allodynia and thermal hyperalgesia was induced by nucleus pulposus in a rat lumbar disc herniation model, similar to a previously reported peripheral nerve injury model. The level of MCP-1 expression was higher in the dorsal horn of the ipsilateral and contralateral sides. These results suggest that MCP-1 might play a role in the maintenance of neuropathic pain.