title: A double-transgenic mouse used to track migrating Schwann cells and regenerating axons following engraftment of injured nerves.
abstract: We propose that double-transgenic thy1-CFP(23)/S100-GFP mice whose Schwann cells constitutively express green fluorescent protein (GFP) and axons express cyan fluorescent protein (CFP) can be used to serially evaluate the temporal relationship between nerve regeneration and Schwann cell migration through acellular nerve grafts. Thy1-CFP(23)/S100-GFP and S100-GFP mice received non-fluorescing cold preserved nerve allografts from immunologically disparate donors. In vivo fluorescent imaging of these grafts was then performed at multiple points. The transected sciatic nerve was reconstructed with a 1-cm nerve allograft harvested from a Balb-C mouse and acellularized via 7 weeks of cold preservation prior to transplantation. The presence of regenerated axons and migrating Schwann cells was confirmed with confocal and electron microscopy on fixed tissue. Schwann cells migrated into the acellular graft (163+/-15 intensity units) from both proximal and distal stumps, and bridged the whole graft within 10 days (388+/-107 intensity units in the central 4-6 mm segment). Nerve regeneration lagged behind Schwann cell migration with 5 or 6 axons imaged traversing the proximal 4 mm of the graft under confocal microcopy within 10 days, and up to 21 labeled axons crossing the distal coaptation site by 15 days. Corroborative electron and light microscopy 5 mm into the graft demonstrated relatively narrow diameter myelinated (431+/-31) and unmyelinated (64+/-9) axons by 28 but not 10 days. Live imaging of the double-transgenic thy1-CFP(23)/S100-GFP murine line enabled serial assessment of Schwann cell-axonal relationships in traumatic nerve injuries reconstructed with acellular nerve allografts.
authors.affiliation: Division of Plastic and Reconstructive Surgery, Washington University in St. Louis School of Medicine, 660 South Euclid Ave Campus Box 8238, St. Louis, MO 63110, USA.
authors.forename: Ayato
authors.initials: A
authors.lastname: Hayashi
authors.forename: Jason W
authors.initials: JW
authors.lastname: Koob
authors.forename: Daniel Z
authors.initials: DZ
authors.lastname: Liu
authors.forename: Alice Y
authors.initials: AY
authors.lastname: Tong
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Hunter
authors.forename: Alexander
authors.initials: A
authors.lastname: Parsadanian
authors.forename: Susan E
authors.initials: SE
authors.lastname: Mackinnon
authors.forename: Terence M
authors.initials: TM
authors.lastname: Myckatyn
mesh_terms: D000818:Animals; D001369:Axons; D002465:Cell Movement; D002474:Cell-Free System / Q000473:pathology / Q000637:transplantation*; D005456:Fluorescent Dyes; D049452:Green Fluorescent Proteins / Q000235:genetics; D049408:Luminescent Agents; D008264:Macrophages / Q000473:pathology; D051379:Mice; D008807:Mice, Inbred BALB C; D008822:Mice, Transgenic / Q000235:genetics; D018613:Microscopy, Confocal; D008854:Microscopy, Electron; D009416:Nerve Regeneration; D009469:Neuromuscular Junction / Q000473:pathology; D012583:Schwann Cells; D012584:Sciatic Nerve / Q000473:pathology / Q000503:physiopathology* / Q000601:surgery*; D013997:Time Factors; D014184:Transplantation, Homologous
chemical_list: C485182:Cyan Fluorescent Protein; D005456:Fluorescent Dyes; D049408:Luminescent Agents; D049452:Green Fluorescent Proteins