Abstract
Polyethylene glycol (PEG)-fusion technologies have been reported to rapidly, effectively, and permanently restore lost behavioral functions within days to several weeks after transecting or ablating portions of mammalian sciatic nerves, the latter injuries best repaired by allografts of viable sciatic nerves. PEG-fusion must result in inappropriate fusions of surviving distal, proximal and/or graft motor and sensory axons having different muscles of origin and/or receptive fields than their proximal axonal connections. Somehow, these inappropriately PEG-fused axons that do not exhibit Wallerian degeneration and/or axons re-innervating target tissues by outgrowth (after at least several weeks) must be responsible for the extensive behavioral recovery at 3 days to 8 weeks. Neither we nor Robinson and Madison have yet published any data on the accuracy of any reinnervation of motoneurons after successful PEG-fusion of a PNS nerve. Accurate data on cellular/molecular mechanisms of axonal specificity and plasticity are important to understand the reasons for the success of PEG-fusion technologies that could produce a paradigm shift in the treatment of traumatic PNS nerve injuries.