A new immunohistochemical method to evaluate the development of vestibular compensation after unilateral labyrinthectomy in rats

Background: Unilateral labyrinthectomy (UL) causes the disappearance of ipsilateral medial vestibular nuclear (ipsi-MVe) activity and induces spontaneous nystagmus (SN), which disappears during the initial process of vestibular compensation (VC). Ipsi-MVe-activity restores in the late process of VC.
Objective: We evaluated the late process of VC after UL in rats and examined the effects of thioperamide (H3 antagonist) on VC.
Materials and methods: MK801 (NMDA antagonist)-induced Fos-like immunoreactive (-LIR) neurons in contra-MVe, which had been suppressed by NMDA-mediated cerebellar inhibition in UL-rats was used as an index.
Results: The number of MK801-induced Fos-LIR neurons in contra-MVe gradually decreased to the same level as that of sham-operated rats 14 days after UL. Thioperamide moved the disappearance of the MK801-induced Fos-LIR neurons 2 days earlier. The number of MK801-induced Fos-LIR neurons in thioperamide-treated rats was significantly decreased, compared with that of vehicle-rats on days 7 and 12 after UL. But, thioperamide did not influence the decline of SN frequency in UL-rats.
Conclusion: There findings suggested that the number of MK801-induced Fos-LIR neurons in contra-MVe was decreased in concordance with the restoration of ipsi-MVe-activity during the late process of VC after UL and that thioperamide accelerated the late, but not the initial process of VC.

内容要旨・審査要旨・論文本文の公開
本論文は，著者Kazunori Matsudaの学位論文として提出され，学位審査・授与の対象となっている。
This is an Accepted Manuscript of an article published by Taylor & Francis in Acta Oto-Laryngologica on 16/04/2019, available online: http://www.tandfonline.com/10.1080/00016489.2019.1599140