A multi-channel collagen scaffold loaded with neural stem cells for the repair of spinal cord injury.

Collagen scaffolds possess a three-dimensional porous structure that provides sufficient space for cell growth and proliferation, the passage of nutrients and oxygen, and the discharge of metabolites. In this study, a porous collagen scaffold with axially-aligned luminal conduits was prepared. In vitro biocompatibility analysis of the collagen scaffold revealed that it enhances the activity of neural stem cells and promotes cell extension, without affecting cell differentiation. The collagen scaffold loaded with neural stem cells improved the hindlimb motor function in the rat model of T8 complete transection and promoted nerve regeneration. The collagen scaffold was completely degraded in vivo within 5 weeks of implantation, exhibiting good biodegradability. Rectal temperature, C-reactive protein expression and CD68 staining demonstrated that rats with spinal cord injury that underwent implantation of the collagen scaffold had no notable inflammatory reaction. These findings suggest that this novel collagen scaffold is a good carrier for neural stem cell transplantation, thereby enhancing spinal cord repair following injury. This study was approved by the Animal Ethics Committee of Nanjing Drum Tower Hospital (the Affiliated Hospital of Nanjing University Medical School), China (approval No. 2019AE02005) on June 15, 2019.

Dynamic changes in the systemic immune responses of spinal cord injury model mice.

Intraspinal inflammatory and immune responses are considered to play central roles in the pathological development of spinal cord injury. This study aimed to decipher the dynamics of systemic immune responses, initiated by spinal cord injury. The spinal cord in mice was completely transected at T8. Changes in the in vivo inflammatory response, between the acute and subacute stages, were observed. A rapid decrease in C-reactive protein levels, circulating leukocytes and lymphocytes, spleen-derived CD4+ interferon-γ+ T-helper cells, and inflammatory cytokines, and a marked increase in neutrophils, monocytes, and CD4+CD25+FOXP3+ regulatory T-cells were observed during the acute phase. These systemic immune alterations were gradually restored to basal levels during the sub-acute phase. During the acute phase of spinal cord injury, systemic immune cells and factors showed significant inhibition; however, this inhibition was transient, and the indicators of these serious disorders gradually returned to baseline levels during the subacute phase. All experiments were performed in accordance with the institutional animal care guidelines, approved by the Institutional Animal Care and Use Committee of Experimental Animal Center of Drum Tower Hospital, China (approval No. 2019AE01040) on June 25, 2019.