Abstract:

Objective   To observe the behavioral difference after the crush injury of facial nerve in rats and determine the expression of CNTF in motoneurons of facial nucleus. Methods   In 30 healthy adult rats, the trunk of right facial nerve were crushed while that of the left nerve was control. The rats were divided into 5 subgroups according to the days after the operation, including 1d, 7d, 14d, 21d and 35d subgroup. During the experiment, the behavioral changes were monitored, while the pathological differences of motoneurons were observed by HE staining and the number of cells was counted. CNTF protein in facial nucleus were detected by immunohistochemical method and analyzed by optical density. Results   The rats showed right facial palsy immediately after the crush injury. The number of neurons in the right side decreased significantly compared with the left side (P<0.01) on the 7th, 14th and 21st day. Some morphological changes were observed, such as deranged cellular structure, cytoplasm vacuolization, or nucleolar margination. The expressions of CNTF increased obviously in the right side on the day of  7th, 14th and 21st day (P<0.01). Conslusion   Nerve crush is a simple, easy and stable way to establish animal model for the reversible facial paralysis. The expression of CNTF protein increases in the motoneurons of facial nucleus after the facial nerve is crushed.

Key words: Facial nerve, Crush injury, Ciliary neurotrophic factor, Facial nucleus