Tracking Schwann cells eight weeks after injection.

(A and A′) cell nuclei labeled with DAPI; (B and B′) GFP⁺ Schwann cells; (C and C′) SC stained for S-100; (D and D′) Overlay images. Arrow indicates transplanted Schwann cell expressing GFP and S-100. (E–H) Immunoelectronmicroscopy for GFP⁺ Schwann cells. (E) Schwann cell labeled with colloidal gold (arrows) myelinating a regenerated fiber; (F) Higher magnification of (E) showing gold particles in SC nucleus and cytoplasm. (G) Tagging with colloidal gold in the myelin sheath of a regenerated myelinated fiber; (H) Tagging with colloidal gold showing well-developed RER in a Schwann cell. (Arrows) Colloidal gold particles; (Stars) Schwann cell nuclei; (Dashed line) External limit of a nerve fiber myelinated by GFP⁺ Schwann cell; (Dotted line) Axon limit; (Asterisk) Schwann cell RER. Bar: 20 µm (A, A′, B, B′, C, C′, D and D′); Bar: 0.2 µm (E and F); 100ηm (G); 0.5 µm (H).