22-07-08(11:31:04)
Authors:
Antal Nógrádi
Institutions:
Department of Ophthalmology
Faculty of Medicine
Albert Szent-Györgyi Clinical Centre
University of Szeged
Szeged, Hungary
Title of abstract : TRANSPLANTATION OF EMBRYONIC MOTONEURONES INTO THE INJURED SPINAL CORD: REPLACEMENT OR RESCUE OF HOST MOTONEURONES?
Abstract text:
Transplantation of embryonic motoneurones into the injured spinal cord is a feasible way to replace motoneurones destined to die. However, grafted embryonic spinal cord neurones not only replace the missing motoneurones but are thought to promote the regeneration of injured ones.
In our models lumbar and cervical segmental injuries were produced where motoneurones were injured by avulsion of the ventral root. In the case of lumbar injuries an embryonic spinal cord graft enriched in motoneurones was placed into affected segment and the avulsed ventral root was reimplanted. The grafted neurones replaced some of the lost motoneurones and induced functional reinnervation of the denervated hindlimb muscles. The grafted animals produced coordinated hindlimb movements and the reinnervated muscles had an EMG activity pattern comparable to that of intact hindlimb muscles. Moreover, considerable degree of morphological connection was found between graft and host neurones showing that the grafted cells were under under the influence of spinal and supraspinal centres.
In the case of cervical spinal injuries the ventral root injury was combined with a partial hemisection. In this model only some of the grafted cells that were placed into the hemisection cavity contributed to the reinnervation of the ventral root while great numbers of injured host motoneurones sent their axons into the reimplanted ventral root. The grafts also induced improved functional reinnervation in their affected forelimbs. Serotonergic and some rubrospinal fibres entered the graft and established synapses on the grafted neurones, while corticospinal fibres avoided the territory of the graft.
