Axon protection by transplanted cells.

<p>(A) GAP43 was up-regulated in the vehicle transplanted crushed optic nerve on day 21, whereas the control optic nerve rarely showed GAP43 staining. At the same time point, the cell transplanted group showed higher GAP43 staining at the site of the crush. *: Crush site. (B) The myelination level of the optic nerve was assessed at the site of crush by FluoroMyelin™ staining of the cryosections. While a huge demyelination was observed in the vehicle-transplanted group, cell-transplanted animals showed higher myelin staining at the site of the crush, presumably due to axonal protection and prevention of secondary demyelination. (C) Axon protection was assessed on day 60 post-transplantation using toluidine blue staining of osmium tetroxide-embedded optic nerves in the semi-thin sections. While the crush reduced the number of axons in the both proximal and distal parts of the lesion in animal treated with dead cell as control or live cells, higher number of axons were protected in the optic nerve of animals treated with hiPSC-NPs transplantation. (D) Quantitative analysis of the preserved axons showed higher number of axons in both proximal and distal parts of lesion in hiPSC-NPs treated rats. a: p<0.05 vs. corresponding site in dead cell treated group, b: p<0.05 vs. proximal to crush in dead cell treated animals.