Regeneration nach verzögerter Nervennaht

The influence of the time delay of a nerve suture on axonal regeneration after nerve lesion is still unknown. We used the rat as an animal model and studied the influence of a 14- and 224-day delayed hypoglossal-facial nerve anastomosis (HFA) and compared results to immediate HFA. After injection of horseradish peroxidase into the whiskerpad we counted the retrogradely labelled neurons in the hypoglossal nucleus 7-112 days after operation to quantify the axonal reinnervation. Additionally, the amplitude of the evoked compound action potential of the whiskerpad was measured after hypoglossal nerve stimulation. By 112 days after immediate HFA only 931 +/- 27 hypoglossal neurons reinnervated the muscle (for 75% of normal innervation). After 14 days delayed HFA reinnervation was accelerated and enhanced with 1293 +/- 81 (104%) neurons. Even after 224 days delayed HFA reinnervation was possible, with 760 +/- 80 neurons (61%) present. We conclude that short-term delayed nerve suture improves axonal reinnervation.