title: Electrical Nerve Stimulation Enhances Perilesional Branching after Nerve Grafting but Fails to Increase Regeneration Speed in a Murine Model.
abstract: Background Electrical stimulation immediately following nerve lesion helps regenerating axons cross the subsequently grafted nerve repair site. However, the results and the mechanisms remain open to debate. Some findings show that stimulation after crush injury increases axonal crossing of the repair site without affecting regeneration speed. Others show that stimulation after transection and fibrin glue repair doubles regeneration distance. Methods Using a sciatic-nerve-transection-graft in vivo model, we investigated the morphological behavior of regenerating axons around the repair site after unilateral nerve stimulation (20 Hz, 1 hour). With mice expressing axonal fluorescent proteins (thy1-YFP), we were able to calculate the following at 5 and 7 days: percentage of regenerating axons and arborizing axons, branches per axon, and regeneration distance and speed. Results Brief stimulation significantly increases the percentage of regenerating axons (5 days: 35.5 vs. 27.3% nonstimulated, p < 0.05; 7 days: 43.3 vs. 33.9% nonstimulated, p < 0.05), mainly by increasing arborizing axons (5 days: 49.3 [4.4] vs. 33.9 [4.1]% [p < 0.001]; 7 days: 42.2 [5.6] vs. 33.2 [3.1]% [p < 0.001]). Neither branches per arborizing axon nor regeneration speed were affected. Conclusion Our morphological data analysis revealed that electrical stimulation in this model increases axonal crossing of the repair site and promotes homogeneous perilesional branching, but does not affect regeneration speed.
authors.affiliation: Plastic and Reconstructive Surgery, Charité-Universitätsmedizin Berlin, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Witzel
authors.affiliation: Department of Orthopaedic Surgery, Johns Hopkins Medical Institutions, Baltimore, Maryland.
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Brushart
authors.affiliation: Department of Plastic and Hand Surgery, University of Freiburg Medical Centre, Freiburg, Germany.
authors.forename: Georgios
authors.initials: G
authors.lastname: Koulaxouzidis
authors.affiliation: Department of Plastic, Aesthetic and Hand Surgery, Otto von Guericke University, Magdeburg, Germany.
authors.forename: Manfred
authors.initials: M
authors.lastname: Infanger
mesh_terms: D000818:Animals; D001369:Axons / Q000502:physiology*; D004558:Electric Stimulation; D004594:Electrophysiology; D008164:Luminescent Proteins / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D023421:Models, Animal; D009416:Nerve Regeneration / Q000502:physiology*; D012584:Sciatic Nerve / Q000293:injuries* / Q000502:physiology / Q000637:transplantation*; D009435:Synaptic Transmission / Q000502:physiology*
chemical_list: D008164:Luminescent Proteins