Figure 1

Spinal cord transection injury and axon tracer application. (A) Newt skeleton showing targeted location of injury. Note, the sacroiliac (SI) joints are not associated with the same vertebra in this animal, thus there are two sacral (S) vertebrae where there is usually one. T, trunk; C, caudal. (B) Intact and (C) completely transected spinal cord viewed from dorsal side. (D) Cartoon showing the location of the targeted injury, the spinal ganglia that supply innervation to the hindlimbs (solid line, primary contribution; dotted line, occasional contribution), and rostral tracer application site. (E) Cross-section of spinal cord about 500 μm away from a tracer application site showing the tracer labels axons and neurons specifically. (F, G) Longitudinal sections through 1-week regenerates. Asterisk, injury site. The tracer was applied to the animal in (F) and not to the animal in (G). Axons were also labeled with the 3A10 antibody. Application of the tracer 6 hours prior to tissue harvest did not alter the overall appearance of the axons at the injury site. cc, central canal; eg, ependymoglia; gm, grey matter; wm, white matter; m, meninges; D, dorsal; V, ventral; R, rostral; C, caudal. Scale bars: 200 μm ((F) and (G) are the same scale).