Bone marrow mesenchymal stem cells injected into rat lumbar dorsal root ganglia induce changes in NPY, galanin and Y1 receptor expression and in pain behavior after sciatic nerve constriction

P.L. MUSOLINO; M.F. CORONEL; T. HÖKFELT; M.J. VILLAR

Atlanta, USA

Congreso; Society for Neuroscience; 2006

Society for Neuroscience

Peripheral nerve injury, such us single ligature nerve constriction (SLNC), triggers neuropathic pain and induces changes in neuropeptide expression. Following brain, spinal cord and peripheral nerve lesions, bone marrow mesenchymal stem cells (MSCs) have been observed to migrate to the injured tissue and mediate functional recovery. In this study, we have analyzed the expression of neuropeptide tyrosine (NPY), galanin and the NPY-Y1 receptor (Y1R) in rat lumbar dorsal root ganglion (DRG) neurons following SLNC of the sciatic nerve and intraganglionic MSC injection. The thermal and mechanical sensitivities of control and experimental animals were assessed using the von Frey and Choi tests before surgery and 1, 3, 7, 14, 21, 28 and 56 days after SLNC. Unilateral SLNC induced an ipsilateral increase in the number of NPY- and galanin- immunoreactive neurons and a decrease in Y1R-positive DRG neurons. This effect was at least partially reversed by local intraganglionic injection of MSCs, but not by bone marrow non-adherent mononuclear cells or phosphate-buffered saline. In parallel, the ipsilateral mechanical and thermal allodynias induced by SLNC were significantly decreased in rats receiving MSCs. These results suggest that MSCs may modulate pain generation after sciatic nerve constriction. Also, our data support the involvement of the peptides galanin and NPY and of the Y1R in the behavioral effects observed after MSC injection.