Figure 6.

Regeneration of rhodamine B (RhB)⁺ RGC axons (red) into cellular sciatic nerve (CSN) or acellular sciatic nerve (ASN) grafts at 21 days after optic nerve transection (ONT). Representative images of longitudinal sections of optic nerve and graft in (A), ivit_CSN/ONT_ASN and (B), ivit_CSN/ONT_CSN groups—note the presence throughout the length of the ONT_CSN graft of RhB⁺ (red) regenerating RGC axons (open arrows) and their limited penetration into the ONT_ASN graft (A,B insets), optic nerve GFAP⁺ astrocyte processes (green) do not enter ONT_ASN grafts, but do enter the proximal region of the ONT_CSN graft (closed arrow) (scale bars in A, B, and D = 200 µm; broken line indicates anastomosis site). (C) Quantification of the number of axons extending 400, 800, and 1200 μm past the anastomosis site into the ONT_CSN graft (*** p < 0.0001). A few axons penetrate the junctional zone of ONT_ASN grafts compared to the numbers extending for long distances into ONT_CSN grafts. (D), anastomosis site in an ivit_CSN/ONT_CSN rat showing the laminin⁺ basal lamina of the optic nerve vasculature (arrow heads) and Schwann cell basal lamina tubes aligned in parallel arrays in the ONT_CSN graft (arrow), with which (E) regenerating RGC axons are associated with the extent of GFAP⁺ astrocyte process (green) invasion and the growth of RhB⁺ RGC axons (red) (scale bars = 150 µm; the broken line indicates the anastomosis site).