Human umbilical cord-derived mesenchymal stromal cells promote sensory recovery in a spinal cord injury rat model

While paralysis is widely appreciated to impact the quality-of-life after spinal cord injuries (SCIs), neuropathic chronic pain may also occur in many cases. In this study, we investigated whether human umbilical cord-derived mesenchymal stromal cells (hUCMSCs) possess the therapeutic potential to reduce neuropathic pain following SCI in rats. Spinal cord hemitransection, which was used as a rat SCI pain model, induced tactile hypersensitivity in the hind paw and hyperexcitability of wild dynamic range neurons in response to natural cutaneous stimuli. Following hemitransection, we transplanted hUCMSCs into the spinal cord. Attenuation of neuronal hyperexcitability was observed in the hUCMSCtreated group compared with that observed in the vehicle-treated group. Immunohistochemistry showed that the transplanted hUCMSCs retained the expression of gammaamino butyric acid (GABA). The results suggest that transplanted hUCMSCs ameliorate GABAergic inhibition in the spinal cord. In summary, the production of GABA plays a critical role in the plasticity of neuropathic pain after implantation of hUCMSCs.