Neuroprotective effects of TJ-23 (Tokishakuyakusan) on adult rat motoneurons following peripheral facial nerve axotomy

Abstract

Objective: We investigated free radical scavenging activity and the possible neuroprotective effect of Tokishakuyakusan (TJ-23) on facial motor nucleus (FMN) motoneurons after peripheral axotomy.

Study design: In 40 adult rats, the right facial nerve was transected at the level of the stylomastoid foramen. Following axotomy, the effects of TJ-23 on nitric oxide synthase were investigated using NADPH-d histochemistry. FMN motoneurons were counted bilaterally in sections stained with cresyl violet.

Results: Rats administered TJ-23 exhibited clear suppression of injury-induced neuronal NADPH-d expression in the ipsilateral FMN when compared to nontreated controls. The number of surviving motoneurons in the ipsilateral FMN was significantly greater among TJ-23-treated rats than nontreated controls on day 56 following axotomy.

Conclusion: The present study demonstrates the neuroprotective effect of TJ-23 after peripheral facial nerve axotomy.

Significance: Antioxidants may have therapeutic potential in traumatic facial nerve dysfunction resulting from head injury, ear surgery, and parotid gland surgery.