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

Abstract

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.

Keywords: Behavior; Collagen; Conditioned culture media; Rats; Spinal cord injuries.

Fig. 1.

BBB scores showing locomotor recovery during the study in the different groups. BBB score, Basso, Beattie, and Bresnahan score; SCI, spinal cord injury; SHED, Stem cells from human exfoliated deciduous teeth; CM, conditioned medium. ^*p<0.05, ^**p<0.01 (Significant differences between the SCI+SHED-CM+Col and other injured groups are indicated).

Fig. 2.

The maximum angle of inclined plane at which the animal could maintain its position for 5 seconds at different time points of the study in the different groups. SCI, spinal cord injury; SHED, stem cells from human exfoliated deciduous teeth; CM, conditioned medium. ^*p<0.05, ^**p<0.01 (Significant differences between the SCI+SHED-CM+Col and other injured groups are indicated).

Fig. 3.

Duration of response to cold stimulus (acetone) showing cold allodynia at different time points of the study in the different groups. SCI, spinal cord injury; SHED, stem cells from human exfoliated deciduous teeth; CM, conditioned medium. ^*p<0.05, ^**p<0.01 (Significant differences between the SCI+SHED-CM+Col and other injured groups are indicated).

Fig. 4.

Beam walk scores during the study in the different groups. SCI, spinal cord injury; SHED, stem cells from human exfoliated deciduous teeth; CM, conditioned medium. ^*p<0.05, ^**p<0.01 (Significant differences between the SCI+SHED-CM+Col and other injured groups are indicated).