Nerve and Spinal Cord Regeneration

Experimental models of nerve injury and methods for assessment of recovery are being used to evaluate treatments that can promote nerve regeneration. These models are directed to clinical problems of urinary incontinence and mechanical forms of nerve injury such as compression and stretching. (Kerns)

Neural Regeneration in (a) Spinal cord, (b) Motoneurons, (c) Pudendal nerve, (d) Regenerated nerve, (e) Neuromuscular. The spinal cord (a) may be damaged by a laminectomy procedure which can produce a scar (blue) attaching to the meninges (LM); the arrow marks a cystic space. (b) In the ventral horn are motoneurons (DM) labeled with a retro-grade tracer (HRP).Their axons traverse the ishiorectal fossa (c) en route to their sphincter targets. The pudendal nerve was crushed to model experimentally incontinence and the target was treated with IGF-I to enhance regeneration. The nerve at the arrow at 56 days post-operative is seen at the EM level (d) where evidence of prior degeneration (stars) and regeneration is seen. Minifascicles (open arrows) enclose new axons, both myelinated and non-myelinated (solid arrows). (e) With silver staining and AChE the motor axons form neuromuscular junctions with the striated muscle fibers of the external urethral sphincter. Experiments with the rat sciatic nerve are also on going in the laboratory; for example, an end-to-side bridge around a partial lesion.