Changes in glial fibrillary acidic protein immunoreactivity in the rat facial nucleus following various types of nerve lesions.

We report about changes on astrocytes in the facial nucleus of the rat following various types of peripheral nerve lesions. Astrocyte-specific glial fibrillary acidic protein (GFAP) was labeled by immunohistochemistry and served as a marker for these changes. Increased GFAP immunoreactivity was found in the facial nucleus on the lesioned side within 2-3 days after axotomy. This change lasted longer (up to 1 year) when axon regeneration was prevented or delayed by placing a metal clip on the proximal nerve stump. Lesion of the trigeminal nerve prior to axotomy reduced the degree of GFAP immunoreactivity. No side differences were observed after botulinum toxin application.