INTRODUCTION
MATERIALS AND METHODS
Contusive SCI model
Group allocation and postoperative care
Isolation, culture, and characterization of MSCs
Impregnation of MSCs onto scaffolds and cell transplantation
![]() | Fig. 1Mesenchymal stem cells (MSCs) were confirmed by scanning electron microscopy before transplantation. Cultured MSCs were seeded onto (A) a PLGA film (IP group), and (B) a chitosan fiber (IC group). The impregnated MSCs on the scaffolds were confirmed by immunofluorescence (IF) staining, which were shown to be PKH 26-positive (× 200). |
Immunofluorescence (IF) staining for identifying MSCs
Neurotrophic growth factor analysis
Functional assessment
Statistical analysis
RESULTS
Phenotype expression of the cultured MSCs
Engraftment of the transplanted MSCs in the injured spinal cord
![]() | Fig. 3Engraftment of the transplanted cells was investigated. (A) IL group: PKH 26-positive MSCs were found along the injection tract as a cluster. (B) IP group: most transplanted MSCs were found around the glial scar at the dorsal side of the injured spinal cord, and the cells tended to invade the cystic scar. (C) IC group: PKH 26-positive MSCs were also found around the glial scar and the cells tended to invade the cystic scar. In each figure, from the left, H & E stain (× 40); H & E stain (× 400); IF stain merged with PKH 26 and DAPI (× 400). Red arrows indicate transplanted MSCs. |
Differentiation of the MSCs in the SCI lesions
![]() | Fig. 4MSCs showed various differentiated cell types according to their transplantation delivery routes. (A) Co-localized IF staining with PKH 26 (red), DAPI (blue), and cell markers (green) for differentiated cells were counted under high-power magnification (× 1,000); cell markers were GFAP for astrocytes, CC-1 for oligodendrocytes, and NeuN for neurons. (B) Astrocytic differentiation was predominant in the IL group; Oligodendrocytic differentiation was predominant in the scaffold groups; Neuronal differentiation in each group showed similar proportions. |
Table 1
Summary of quantitative analysis of engraftment and differentiation of the transplanted cells by immunofluorescence (IF) staining

Real-time RT-PCR for neurotrophic factors
![]() | Fig. 5Expression of brain-derived neurotrophic factor (BDNF) and neuronal growth factor (NGF) genes were analyzed by RT-PCR. (A) BDNF mRNA expression in the transplanted groups was significantly higher than in the control group. (B) NGF mRNA expression in the IC group was numerically higher than in the control group, with borderline statistical significance (mRNA: messenger ribonucleic acid). |
Western blot analysis for neurotrophic factors
![]() | Fig. 6Neurotrophic growth factors were quantified by Western blot analysis. (A) The relative optical densities of BDNF in the transplanted groups (IL, IP, and IC) were significantly higher than that of the control group. (B) The relative optical densities of NGF in the transplanted groups were significantly higher than that of the control group. |
Functional recovery of the rat hindlimbs
![]() | Fig. 7All rats including the control showed a gradual recovery of hindlimb function for 6 weeks following spinal cord injury. The Basso, Beattie and Bresnahan (BBB) scores of scaffold groups at every week were consistently higher than those of the IL group, throughout the entire 6 weeks. The IC group showed the highest BBB score at the final follow-up. |