Resumo

Strategies aiming to improve spinal cord regeneration after trauma are still challenging neurologists and neuroscientists throughout the world. Many cell-based therapies have been tested by several groups, with limited success in terms of the functional outcome. However, there are not many studies using neither human cells nor being done in the chronic phase after lesion. In this study, we investigated the effects of human dental-pulp cells in a mouse model of compressive spinal cord injury. These cells present some advantages, such as the ease of the extraction process, and expression of trophic factors and embryonic markers from both ecto- and mesenchymal components. Young adult female C57/Bl6 mice were subjected to laminectomy at T9 and compression of the spinal cord with a vascular clip, for 1 minute. The cells were transplanted 7 days or 28 days after the lesion, in order to compare the recovery when treatment is applied in a subacute or chronic phase. We performed quantitative analysis of white-matter preservation, trophic-factor expression and quantification, and ultrastructural and functional analyses. Our results for the HDPC-transplanted animals, showed better white-matter preservation than the DMEM groups, higher values of BDNF tissue expression, better tissue organization, and the presence of many axons being myelinated by either Schwann cells or oligodendrocytes, in addition to the presence of some healthy-appearing intact neurons with synapse contacts on their cell bodies. The functional analysis also showed locomotor improvement in these animals. So, our results suggest that the cellular therapy used in this work showed a beneficial effect either in acute or chronic phase, indicating that this treatment increases white matter sparing, nervous fibers preservation and contributes to functional recovery. In addition, we also conclude that HDPC may be feasible candidates for therapeutic intervention after spinal cord injury and Central Nervous System disorders in humans .