The action of topical basic fibroblast growth factor in facial nerve regeneration

To analyze the influence of the topical use of basic fibroblast growth factor (bFGF) in the regeneration of the facial nerve in rats.

Experimental study.

Twenty-eight Wistar adult male rats underwent complete section of the facial nerve trunk, followed by end-to-end anastomosis with epineural sutures. An osmotic minipump equipped with a delivery catheter was implanted subcutaneously near the neural anastomosis. During the subsequent 14 days, 14 animals received a solution containing 25 microg/ml of bFGF, 250 UI/ml of sodium heparin, and 1,000 microg/ml of human albumin diluted in Ringer lactate, and 14 animals received a control solution of the same components without bFGF. To evaluate facial nerve regeneration, the number of myelinated fibers evident on histologic sections was counted on the 14th (7 experimental and 8 control animals) and the 28th days (7 experimental and 6 control animals) after surgery, and the facial movements of vibrissae and the blink reflex were evaluated on alternate days until the 28th day.

On histologic evaluation, the number of myelinated fibers was similar between groups on the 14th day and greater in the group that received bFGF on the 28th day. Behavioral evaluation showed that the animals of the bFGF group presented better functional results between the 6th and 16th days for the blink test and the 14th to the 16th days for vibrissae movements.

This study showed that the regeneration of the facial nerve occurred earlier and resulted in significantly more myelinated nerve fibers in the animals that received topical bFGF.