Microtransplantation of neural cells into adult rat brain

Epithelioid ("type 1") astrocytes and hippocampal neurons have been stereotaxically grafted into adult rat brain by a new "microtransplantation" method and the results of grafting assessed at various survival times by conventional histological methods using light and electron microscopes. The extent of bleeding that accompanied grafting was assessed by peroxidase staining of extravascular red cells. Grafts were small, compact and reproducible in terms of their volume and location. Implantation was achieved with very little trauma to host tissue. There was no apparent disruption of host tissue adjacent to the graft and very little damage to host blood vessels from earliest survival times. Donor astrocytes were in direct contact with cells of the host immediately after grafting. This situation was compared with conventional implantation of astrocytes in which much damage, necrosis and bleeding occurred and for which cells of graft and host were initially isolated from one another. Microtransplanted astrocytes were observed to migrate. Similar, comparatively non-traumatic microtransplantation of hippocampal neurons was also carried out. Long-term survival of grafted neurons was demonstrated.