The Effect of Etanercept and Methylprednisolone on Functional Recovery of the Facial Nerve After Crush Injury

Abstract

Objective: To establish whether etanercept, a TNF-alpha antagonist, is an alternative and effective treatment on facial nerve after crush injury.

Method: Fifty-four rats underwent exposure of the left main trunk of the facial nerve followed by a standard crush injury. Animals were randomly divided into 3 groups: control group, methylprednisolone-treated group, and etanercept-treated group. All these groups were divided into 2 subgroups; animals were sacrificed on the 4th day after facial crush injury in the first subgroup and on the 28th day in the second subgroup. Functional recovery of vibrissae movement, eye blink reflex, and vibrissae orientation was measured on a 3-point scale (1 = no recovery, 2 = partial recovery, and 3 = complete recovery) during the recovery process. Facial nerve, from the main trunk at the stylomastoid foramen to the zygomatic, buccal, and marginal branches, were dissected and postfixed in the same fixative. The paraffin sections were studied with macrophage marker, GAP-43 and T Cell Marker.

Results: Animals receiving etanercept demonstrated significantly better functional recovery compared with control and methylprednisolone-treated animals. The etanercept-treated group showed highest GAP-43 immunoreactivity in the nerves. After the macrophage marker and T cell marker staining, the etanercept and methylprednisolone groups demonstrated statistically significant difference compared with the control group (p < 0.001).

Conclusion: The present study demonstrates accelerated functional recovery associated with etanercept treatment after facial nerve crush injury in rats.