Accelerated recovery following polyamines and aminoguanidine treatment after facial nerve injury in rats

Accelerated axon regeneration is of paramount importance for improved functional recovery after motor nerve injuries. Following injury of their axon neurones undergo a series of changes, termed the axon reaction, aimed at survival and regeneration of a new axon. We and others have found that early treatment with exogenous polyamines can enhance neuronal survival and accelerate the rate of axon regeneration and functional recovery after sympathetic and motor (sciatic) nerve injuries. Results of the present study corroborate the previous findings and demonstrate that after facial nerve injury in adult rats, polyamine treatment can accelerate the early phases of motor function recovery (vibrissae movement). Treatment with aminoguanidine, an inhibitor of several oxidation reactions, produced a further improvement at the early phase of functional recovery. In the facial nucleus, the injury-induced transient reduction in the activity of the acetylcholine synthesizing enzyme choline acetyltransferase was not affected by the treatment. After nerve injury in 5-day-old male rats, polyamines and aminoguanidine treatment exerted a minor neuroprotective effect (127.6% surviving neurones compared to control). We conclude that polyamines and aminoguanidine may have therapeutic potential in the acceleration of recovery after nerve injuries.