L-Thyroxine Improves Vestibular Compensation in a Rat Model of Acute Peripheral Vestibulopathy Cellular and Behavioral Aspects

Authors
G Rastoldo, E Marouane, N El-Mahmoudi et al

Lab
Aix Marseille Universite-CNRS, Laboratoire de Neurosciences Cognitives, Marseille, France

Journal
Cells

Abstract
Unilateral vestibular lesions induce a vestibular syndrome, which recovers over time due to vestibular compensation. The therapeutic effect of L-Thyroxine (L-T4) on vestibular compensation was investigated by behavioral testing and immunohistochemical analysis in a rat model of unilateral vestibular neurectomy (UVN). We demonstrated that a short-term L-T4 treatment reduced the vestibular syndrome and significantly promoted vestibular compensation. Thyroid hormone receptors (TRalpha and TRbeta) and type II iodothyronine deiodinase (DIO2) were present in the vestibular nuclei (VN), supporting a local action of L-T4. We confirmed the T4-induced metabolic effects by demonstrating an increase in the number of cytochrome oxidase-labeled neurons in the VN three days after the lesion. L-T4 treatment modulated glial reaction by decreasing both microglia and oligodendrocytes in the deafferented VN three days after UVN and increased cell proliferation. Survival of newly generated cells in the deafferented vestibular nuclei was not affected, but microglial rather than neuronal differentiation was favored by L-T4 treatment.

BIOSEB Instruments Used:
Dynamic Weight Bearing 2.0 (BIO-DWB-DUAL)