Expression of c-Jun and KROX-20 Following Facial Nerve Injury and Recovery in Rats

BACKGROUND: This study evaluated whether recovery from facial paralysis was associated with the expression of Krox-20 and c-Jun genes that are shown to be related to facial nerve regeneration after facial nerve compression and cutting. METHODS: The left facial nerves of 24 male Sprague–Dawley rats aged 6 weeks were subjected to crushing or cutting injury. Whisker movements of the vibrissae muscle and blink reflexes of the eyelids were measured on days 4 and 14 after facial nerve injury. The facial nerves on both sides were removed, and the expression of c-Jun and Krox-20 proteins was evaluated by Western blotting. RESULTS: The level of expression of Krox-20 on day 4 was lower in the crushing group, especially in the cutting group than in the control group (P < .05), but there was no statistically significant difference on day 14 (P > .05). The expression of c-Jun expression was significantly higher in the crushing and cutting groups than in the control group on days 4 and 14 (P < .05). CONCLUSION: The degree of facial paralysis was more severe and the recovery rate was lower in the cutting group than in the crushing group. The levels of expression of Krox-20 and c-Jun were associated with facial nerve regeneration after facial nerve injury.