title: Axon and Schwann cell partnership during nerve regrowth.
abstract: Regeneration of peripheral nerve involves an essential contribution by Schwann cells (SCs) in collaboration with regrowing axons. We examined such collaboration between new axons and Schwann cells destined to reform peripheral nerve trucks in a regeneration chamber bridging transected rat sciatic nerves. There was a highly intimate "dance" between axons that followed outgrowing and proliferating SCs. Axons without SCs only grew short distances and almost all axon processes had associated SC processes. When regeneration chambers were infused through an external access port with local mitomycin, a mitosis inhibitor, SC proliferation, migration and subsequent axon regrowth were dramatically reduced. Adding laminin to mitomycin did not reverse this regenerative lag and indicated that SCs provide more than laminin synthesis alone. Laminin infused alone supplemented endogenous laminin and facilitated first SC then axon regrowth. "Wrong way" misdirected axons were associated with misdirected SC processes and were more numerous in bridges exposed to mitomycin, but were fewer in laminin supplemented bridges. Later, by 21 days, there was myelinated axon repopulation of regenerative bridges but those exposed to mitomycin alone at early time points had substantial impairments in axon investment. Reforming peripheral nerve trucks involves a very close and intimate relationship between axons and SCs that must proliferate and migrate, facilitated by laminin.
authors.affiliation: University of Calgary, Department of Clinical Neuroscience, Calgary, Alberta, Canada.
authors.forename: Yuan Yuan
authors.initials: YY
authors.lastname: Chen
authors.forename: David
authors.initials: D
authors.lastname: McDonald
authors.forename: Chu
authors.initials: C
authors.lastname: Cheng
authors.forename: Brooks
authors.initials: B
authors.lastname: Magnowski
authors.forename: Jeff
authors.initials: J
authors.lastname: Durand
authors.forename: Douglas W
authors.initials: DW
authors.lastname: Zochodne
mesh_terms: D000818:Animals; D001369:Axons / Q000187:drug effects / Q000502:physiology / Q000648:ultrastructure*; D019771:Axotomy; D002450:Cell Communication / Q000187:drug effects / Q000502:physiology; D049108:Cell Enlargement / Q000187:drug effects; D002465:Cell Movement / Q000187:drug effects / Q000502:physiology; D007150:Immunohistochemistry; D007797:Laminin / Q000494:pharmacology; D008297:Male; D016685:Mitomycin / Q000494:pharmacology; D009416:Nerve Regeneration / Q000187:drug effects / Q000502:physiology*; D019384:Nucleic Acid Synthesis Inhibitors / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012583:Schwann Cells / Q000166:cytology* / Q000187:drug effects / Q000502:physiology; D012584:Sciatic Nerve / Q000166:cytology / Q000187:drug effects / Q000502:physiology; D014855:Wallerian Degeneration / Q000473:pathology
chemical_list: D007797:Laminin; D019384:Nucleic Acid Synthesis Inhibitors; D016685:Mitomycin