Effects of superenriched environment on rat facial nerve injury

OBJECTIVE: The objective of this study was to analyze the effects of unilateral axonomic rats' facial nerve, and the capability of the enriching ambience modify the recovery evolution, after the peripheral nerve transection. METHODS: Adult male Wistar rats (200-250g), were divided into groups: Control (n=10), Whiskerectomy (n=13), Divulsion of the neuro-muscular coats (n=11), and Right unilateral facial nerve axonomy (n=14). Those groups were subdivided into animals lodged in normal environment and enriched environment. The sensory-motor changes originated after facial nerve lesions were analyzed through clinic signals, as the eyelid reflexes and snout deviation. Motor behavior was analyzed one day before, and 1-56 days after treatment by specific tests as the Open Field and the Wall Facing. The statistical test applied was the TWO-WAY ANOVA, p<0.05. RESULTS: The peripheral transection on animals' facial nerve until the 35th day induced whisker paralysis, loss of ipsilateral palpebral reflexes, and contralateral snout deviation to the lesion, with recovery functions in 56 days. There was no difference between the recoveries of the animals lodged in normal or enriched environment (p>0.05). CONCLUSIONS: The unilateral axonomy of rats' facial nerve induces deficiencies in the lesioned hemiface, behavior alterations, and spontaneous lesion recovery in 56 days. According to the analyzed tests, maintaining animals in enriched environment after peripheral nerve transection do not alters the recovery time.