Bone marrow stromal cells injected into lumbar dorsal root ganglia induce changes in thermal and mechanical sensitivities after sciatic nerve constriction

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

Washington DC, USA

Congreso; Society for Neuroscience; 2005

Society for Neuroscience

Single ligature nerve constriction (SLNC) and Bennett neuropathic pain models have been used for the study of pain triggered by peripheral nerve injury. Medium (40-80%) SLNC has been demonstrated to be the most effective in inducing allodynia-like pain behavior. Bone marrow stromal cells (MSCs) have been involved in migration and functional recovery after traumatic injured rat brain and spinal cord. In this study we have analyzed changes in thermal and mechanical pain behavior in animals following SLNC of the sciatic nerve (SN), and also after SLNC and MSC injection into the L4 DRG. Mononuclear cell fraction of whole bone marrow from Sprague-Dawley rats were isolated using a density gradient and plated. MSCs were isolated by their adherence to plastic, cultured until they reached confluence, labeled with Hoechst 33258 and harvested using trypsin-EDTA. Four groups of animals with medium SLNC were prepared. The first group was injected with 300.000 MSCs cells into the L4 DRG. The second group was L4 DRG injected with bone marrow non adherent mononuclear fraction cells. The third group was only constricted and the fourth was the saline sham. Animals were tested for mechanical and thermal withdrawal thresholds before surgery and after 1, 3, 7 days using Von frey and Choi tests respectively. The results showed a normal pain behavioral pattern before lesion and in contralateral footpad of experimental animals. SLNC animals developed ipsilateraly mechanical and thermal allodynia. Animals subjected to SLNC and treatment with MSCs showed a significant decrease in mechanical and thermal allodynia. Animals treated with MCF cells or saline showed no changes in pain response. These results suggest a protective function of MSCs on pain generation in sciatic nerve constricted animals. Further studies should be carried out to evaluate the role of MSCs injected after a peripheral nerve lesion.