Human mesenchymal stem cells implantation into the degenerated coccygeal disc of the rat

Abstract

In this study, the authors explored the effect of human mesenchymal stem cell (MSC) implantation on the restoration of degenerative intervertebral discs (IVDs) in the rat. A unique rat coccygeal model was used to investigate the effects of transplanting human MSCs and to examine MSC survival in degenerative discs. MSC implantations into rat coccygeal IVDs were performed at 2 weeks post-injury. Radiologic and histologic evaluations were performed at 2, 4, 6, and 8 weeks post-injury. MSC-injected segments (TS) retained disc height and signal intensity, but injured non-injected segment (IS) progressively lost disc height. Pathological results revealed that the TS group showed relative restoration of the inner annulus structure; however, the IS group showed destruction of the inner annulus structure. Immunohistochemical staining using Anti-Human Nucleic Antibody (#MAB1281 Chemicon) revealed positive staining in the TS group at 2 weeks post-transplantation (4 weeks post-injury). This study shows that human MSCs survive for 2 weeks after transplantation into the IVDs of rats, and that MSCs increased the heights and signal intensities of intervertebral disc.

Figures

Fig. 1

MRI images of a normal control segment (CS), a MSC transplantation segment (TS), and an only injured segment (IS) taken every 2 weeks after disc injury. MCSs were transplanted at 2 weeks post-injury. TS showed much higher T2-weighted signal intensities than IS

Fig. 2

Graphical representation of disc height changes. Only injured segment (IS) showed progressive decreases in disc height, whereas MSC transplantation segment (TS) did not

Fig. 3

Signal intensities of discs in T2 weighted images: the signal intensities of MSC transplantation segment (TS) were greater than those of only injured segment (IS)

Fig. 4

A-1, 2 Control segments (CS) showed an oval nucleus with no collapse of the inner annular structure (40×, 200×). B-1, 2 Only injured segments (IS) showed collapse of the inner annulus morphology at 8 weeks post-injury (40×, 200×). C-1, 2 MSC transplantation segments (TS) showed relatively good preservation of the inner annulus structure with minimal fibrosis in the nuclear region (40×, 200×)

Fig. 5

a Staining with DAPI (4′,6-diamidino-2-phenylindole), b immunohistochemical staining with Anti-human Nucleic Antibody (ANA Ab), c a merge of (a) and (b) in the discs of MSC transplantation segments (TS) at 4 weeks post injury (2 weeks post transplantation) revealed positive staining (arrow), which confirmed MSC survival (dotted arrow) (200×)