title: In vivo MRI of olfactory ensheathing cell grafts and regenerating axons in transplant mediated repair of the adult rat optic nerve.
abstract: The purpose of the present study was to use magnetic resonance imaging (MRI) as a tool for monitoring transplant-mediated repair of the adult rat visual pathway. We labelled rat olfactory ensheathing cells (OECs) using micron-sized particles of iron oxide (MPIO) and transplanted them by: i) intravitreal injection (ivit) and ii) intra-optic nerve (ON) injection (iON) in adult rats with ON crush (ONC) injury. We applied T(2)-weighted MRI and manganese-enhanced MRI (MEMRI) to visualise transplanted cells and ON axons at specific times after injury and cell engraftment. Our findings demonstrate that ivit MPIO-labelled OECs are unequivocally detected by T(2)-weighted MRI in vivo and that the T(1)-weighted 3D FLASH sequence applied for MEMRI facilitates simultaneous visualisation of Mn(2+-) enhanced regenerating retinal ganglion cell (RGC) axons and MPIO-labelled OEC grafts. Furthermore, analysis of MRI data and ultrastructural findings supports the hypothesis that iON OEC transplants mediate regeneration and remyelination of RGC axons post injury.
authors.affiliation: Department of Circulation and Medical Imaging, Norwegian University of Science and Technology, Trondheim, Norway. ioanna.sandvig@ntnu.no
authors.forename: Ioanna
authors.initials: I
authors.lastname: Sandvig
authors.forename: Marte
authors.initials: M
authors.lastname: Thuen
authors.forename: Linh
authors.initials: L
authors.lastname: Hoang
authors.forename: Øystein
authors.initials: Ø
authors.lastname: Olsen
authors.forename: Thomas C P
authors.initials: TC
authors.lastname: Sardella
authors.forename: Christian
authors.initials: C
authors.lastname: Brekken
authors.forename: Kåre E
authors.initials: KE
authors.lastname: Tvedt
authors.forename: Susan C
authors.initials: SC
authors.lastname: Barnett
authors.forename: Olav
authors.initials: O
authors.lastname: Haraldseth
authors.forename: Martin
authors.initials: M
authors.lastname: Berry
authors.forename: Axel
authors.initials: A
authors.lastname: Sandvig
mesh_terms: D000818:Animals; D001369:Axons / Q000473:pathology*; D058948:Cell Tracking / Q000379:methods; D005260:Female; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009416:Nerve Regeneration; D009830:Olfactory Bulb / Q000473:pathology* / Q000637:transplantation*; D020221:Optic Nerve Injuries / Q000473:pathology* / Q000503:physiopathology / Q000601:surgery*; D051381:Rats; D011916:Rats, Inbred F344; D016896:Treatment Outcome