Figure 4.

ES cell-derived neural progenitors induced using the 4−/4+ retinoic acid method [40, 43, 44] and transplanted into an injury-induced cyst differentiated into central nervous system-type neurons. (A, B): Transplanted ES cells expressed GFP within the center of the transplant. (C): One week after transplantation, ES cell-derived cells (green) had differentiated into neurons displaying ChAT (red) immunoreactivity (yellow indicates double labeling with GFP (green) and ChAT (red)). Orthogonal views of this image are outlined in green and red and are represented within the confocal image with their respective lines. (D–G): Hoechst nuclear counterstain (D, blue) identifies another transplanted ES cell (green [E]) that expressed GFP (green [E]) and ChAT ([F], red; [G], merge). Scale bars = 1 mm (A), 10 μm. (B–G). Differentiation of transplanted ES cells within the inhibitory microenvironment of the CSPG scar. (H): Percentage quantification of neural phenotypes inside and outside the cyst scar. (I): Photomicrograph illustrating that a majority of GFP+ cells that migrated out of the cavity were immunopositive for NG2. Yellow box inset from (I) shows individual NG2 labeling at higher magnification. Student’s t test was used. ∗, p < .05; ∗∗, p < .01. Transplanted cells shown here were derived from the B5 GFP ES cell line. Scale bars = 20 μm (I). Abbreviations: ChAT, choline acetyltransferase; ES, embryonic stem; GFAP, glial fibrillary acidic protein; GFP, green fluorescent protein; NG2, nerve glial antigen 2.