Neural progenitors promote axon growth in vitro and ex vivo but not following injury.
Following an injury to the dorsal roots primary sensory afferents fail to regenerate past the hostile dorsal root entry zone (DREZ), the interface between the peripheral and central nervous system. Neural progenitor cells have previously been utilised as a cellular replacement therapy in a variety of CNS injury models. Here we show for the first time that NPCs are capable of promoting neurite outgrowth from adult sensory neurons in vitro and ex vivo cryo-cultures. The effectiveness of NPCs as a potential means of promoting regeneration of primary afferents across the DREZ was assessed following rhizotomy at the cervical level in the adult rat. Adult rats were subjected to rhizotomy of the dorsal roots between C(5)-T(1) which were then reanastamosed. In conjunction with the rhizotomy NPCs were delivered at the DREZ. NPCs survived transplantation and were observed to differentiate predominantly into glia. Regeneration of the dorsal root fibers was assessed with immunhistochemical analysis of the large and small diameter peptidergic and non-peptidergic afferents. Although afferents appeared near to the DREZ there was little regeneration beyond the DREZ. Furthermore, no significant improvement was observed in behavioural tasks.
Webber
Daniel J
DJ
Brain Repair Centre, University of Cambridge, Forvie Site, Cambridge, CB2 2PY.
Yip
Ping
P
Bradbury
Elizabeth J
EJ
Minger
Stephen L
SL
McMahon
Stephen B
SB
D000818:Animals; D001369:Axons; D002478:Cells, Cultured; D005727:Ganglia, Spinal; D009416:Nerve Regeneration; D017207:Rats, Sprague-Dawley; D019051:Rhizotomy; D013126:Spinal Nerve Roots