Increased Nerve Growth Factor Level in the Distal Stump of Transected Sciatic Nerve in Relation to Aging and Its Application for Neural Grafting

The nerve growth factor (NGF) level in the distal stump of mouse sciatic nerve transected 24 h before increased significantly compared with that in the nontransected contralateral side. This level was higher in aged (24-month-old) mice than in aging (12-month-old) or in young (1-month-old) mice. Adrenal medullary tissue mixed with the pretransected (24 h before) distal stump of the sciatic nerve of aged mice was cografted into the ipsilateral striatum of aged mice with a unilateral 6-hydroxydopamine lesion of dopaminergic system. Two and 4 weeks after transplantation, cografted mice showed partial functional compensation in amphetamine-induced motor asymmetry while mice with adrenal grafts alone did not show the functional recovery. The immunocytochemical staining of tyrosine hydroxylase revealed large numbers of chromaffin cells surviving in cografted animals. It is concluded that NGF level in the distal stump of pretransected peripheral nerve is increased even in aged animals and cografting of this nerve stump with adrenal medulla can be effectively utilized in aged animals with nigrostriatal insufficiency.