Figure 7

Stage IV of tail regeneration. Eublepharis macularius. (A,B) Gross morphology of the regenerating tail in caudal (A) and dorsal view (B). Regenerating tail is dome-shaped with a length: diameter less than 0.5. Serial sections stained with Masson's trichrome (C,D,F) or immunostained for PCNA (E) (dorsal towards top of page, autotomy surface to right). (C) Sagittal section of tail with the developing dome-shaped blastema (right side of image). The spinal cord (stained pink) is centrally positioned and continues into the blastema as the ependymal tube (stained pink). Ventral and parallel to the spinal cord is the notochord. The notochord abruptly ends at the blastema. The blastema is capped by a thick wound epithelium (stained red). (D) Closer view of the region identified in panel (C) taken from a different section. The interface of original epidermis and wound epithelium occurs at the epidermal downgrowth. (E) Closer view of the region identified in panel (C) taken from a different section. Ependymal tube and surrounding blastema is immunostained for PCNA (brown), to identify proliferating cells, and counterstained with hematoxylin (blue). (F) Closer view of a dorsal root ganglion with regenerating axons (strained red) passing into the blastema (black arrow). at, adipose tissue; bl, blastema; bv, blood vessel; ch, chevron; cv, caudal vein; dg, epidermal downgrowth; de, dermis; em, epaxial muscle; et, ependymal tube; id, intervertebral disc; no, notochord; ns, neural spine; oe, original epithelium; sc, spinal cord; sp, arterial sphincter; we, wound epithelium. Scale bars: c = 500 μm; d,e = 20 μm; f = 100 μm.