c-Fos expression in the mouse brainstem after unilateral labyrinthectomy

Conclusion. The results indicated that the vestibular, prepositus hypoglossal, and inferior olive nuclei were activated after unilateral labyrinthectomy in mice like in other species. It is expected that the application of the present procedure to appropriate gene-deficient mice will elucidate the mechanism of the process of vestibular compensation. Objective. Vestibular compensation is attributed to functional and structural reorganization of neural networks in the central vestibular system, but its precise mechanism is still not clear. c-Fos protein is used as a marker of neuronal activation, because of its very limited expression in the normal state and rapid appearance after external stimulation. Previous reports, investigating c-Fos expression after unilateral labyrinthectomy were made in rats and guinea pigs, but not in the mouse brainstem. Materials and methods. For future application to the gene knockout mouse, we examined c-Fos expression in the mouse after unilateral labyrinthectomy. Results. Twenty-four hours after surgery, significantly increased c-Fos positive cells were observed in the bilateral medial vestibular nucleus (MVe), bilateral spinal vestibular nucleus (SpVe), contralateral prepositus hypoglossal nucleus (PrH), and contralateral inferior olive nucleus (IO).