Sensory and Motor Behavior Evidences Supporting the Usefulness of Conditioned Medium from Dental Pulp-Derived Stem Cells in Spinal Cord Injury in Rats

Study Design: Experimental animal study. Purpose: This study aimed to assess effects of conditioned medium (CM) of dental pulp-derived stem cells loaded in collagen hydrogel on functional recovery following spinal cord injury (SCI). Overview of Literature: SCI affects sensory and motor functions, and behavioral recovery is the most essential purpose of therapeutic intervention. Recent studies have reported that CM from dental pulp-derived stem cells has therapeutic benefits. In addition, collagen hydrogel acts as a drug delivery system in SCI experiments. Methods: Stem cells from human exfoliated deciduous teeth (SHEDs) were cultured, and SHED-CM was harvested and concentrated. Collagen hydrogel containing SHED-CM was prepared. The rats were divided into five groups receiving laminectomy, compressive SCI with or without intraspinal injection of biomaterials (SHED-CM), and collagen hydrogel with or without SHED-CM. Basso, Beattie, and Bresnahan (BBB) scoring, inclined plane, cold allodynia, and beam walk tests were performed for 6 weeks to assess locomotor, motor, sensory, and sensory-motor performances, respectively. Results: Scores of the rats receiving SHED-CM loaded in collagen hydrogel were significantly better than those of the other injured groups at 1-week post-injury for BBB, 2 weeks for inclined plane, 2 weeks for cold allodynia, and 4 weeks for beam walk tests (p< 0.05). The differences remained significant throughout the study. Conclusions: Intraspinal administration of SHED-CM loaded in collagen hydrogel leads to improved functional recovery and proposes a cell-free therapeutic approach for SCI.