10 février 2012 5 10 /02 /février /2012 07:49
Polyethylene Glycol Repairs Severed Nerves in Rats Two studies show PEG-induced sealing of axons after transaction or cut- or crush-severance TUESDAY, Feb. 7 (HealthDay News) -- Polyethylene glycol (PEG) may be useful for repairing severed nerves, according to two experimental studies published online Feb. 3 in the Journal of Neuroscience Research. Christopher S. Spaeth, from the University of Texas at Austin, and colleagues measured the ability of rat hippocampal B104 cells or rat sciatic nerves to repair transected neurites in vitro or transected axons ex vivo. In both preparations, endogenous sealing was enhanced by calcium (Ca²+)-containing solutions and decreased by Ca²+-free solutions. At concentrations of 10-50 mM, PEG sealed the cut ends of the B104 cells and rat axons within seconds, independent of Ca²+. George D. Bittner, Ph.D., also from the University of Texas at Austin, and colleagues investigated PEG-sealing and fusion. Following complete cut- or crush-severance of rat sciatic nerves, morphological continuity, action potentials, and behavioral function were consistently and rapidly restored. A hypotonic Ca²+-free saline containing antioxidants prevented opening and resealing of severed axonal ends in sciatic nerves in vivo and ex vivo, and in rat B104 cells in vitro. A hypotonic solution of PEG opened closely apposed axonal ends to induce their membranes to fuse, independent of any endogenous sealing mechanism. Ca²+-containing isotonic saline induced sealing of remaining plasmalemmal holes. "Our PEG-fusion protocols may indeed be quickly translatable to important clinical procedures that dramatically and chronically restore within minutes to days much behavior lost by cut or crush axonal severance, a result not obtained with any other chemical or surgical treatment described to date," Bittner and colleagues conclude.