Intrathecal spinal progenitor cell transplantation for the treatment of neuropathic pain

Injury to, or dysfunction of, the nervous system can lead to spontaneous pain, hyperalgesia, and/or allodynia. It is believed that the number and activity of GABAergic neurons gradually decreases over the dorsal horn. Glutamic acid decarboxylase (GAD) immunocompetence has been demonstrated on spinal progenitor cells (SPCs) cultivated in vitro. The intrathecal implantation of these cultivated progenitor cells may provide a means of alleviating neuropathic pain. Chronic constriction injury (CCI) of the sciatic nerve was used to induce chronic neuropathic pain in the hind paw of rats. SPCs (1 × 10⁶) were implanted intrathecally on the third day after the CCI surgery. The behavioral response to thermal hyperalgesia was observed and recorded during the 14 days postsurgery. Various techniques were utilized to trace the progenitor cells, confirm the differentiation, and identify the neurotransmitters involved. GAD immunoactivity was revealed for 65% of the cultivated spinal progenitor cells in our study. We also determined that transplanted cells could survive more than 3 weeks postintrathecal implantation. Significant reductions were demonstrated for responses to thermal stimuli for the CCI rats that had received intrathecal SPC transplantation. A novel intrathecal delivery with SPCs reduced CCI-induced neuropathic pain.