Injection of Mononuclear Stem Cells from Human Umbilical Cord and Placenta into Mice after 3 and 6 weeks of Experimental Spinal Cord Lesion

Abstract Study design: experimental study. Objective: To evaluate nerve regeneration and motor recovery in Balb C mice with surgically induced paraplegia in response to the use of mononuclear stem cells, in the chronic phase, from human umbilical cord and placental blood after 3 weeks and 6 weeks of spinal cord injury (SCI). Setting: Spinal Cord and Nervous Trauma Studies Laboratory, Institute of Orthopedics and Traumatology, Hospital das Clínicas, University of São Paulo. Methods: 48 mice were divided into 6 groups of 8 animals. Group 1 received stem cells 3 weeks after SCI, group 2, six weeks later after SCI. In group 3, saline solution was injected at the injury site 3 weeks after SCI and in group 4, 6 weeks later. Group 5 was submitted only to SCI and group 6 to laminectomy only. The scales used for motor assessment were BMS and MFS for 12 weeks. Results: The intervention groups showed motor improvement with statistical significance. In the histopathological analysis, the intervention groups showed a lower degree of injury (p<0.05). Regarding axonal sprouting, the intervention groups showed an increase in axonal sprouting, with statistical significance in the caudal portion. Conclusions: the use of stem cells in mice in the chronic phase, after 3 and 6 weeks of spinal cord injury, brings functional and histopathological benefits for them.