| First Author | Cordas EA | Year | 2012 |
| Journal | Endocrinology | Volume | 153 |
| Issue | 3 | Pages | 1548-60 |
| PubMed ID | 22253431 | Mgi Jnum | J:182543 |
| Mgi Id | MGI:5315819 | Doi | 10.1210/en.2011-1834 |
| Citation | Cordas EA, et al. (2012) Thyroid hormone receptors control developmental maturation of the middle ear and the size of the ossicular bones. Endocrinology 153(3):1548-60 |
| abstractText | Thyroid hormone is critical for auditory development and has well-known actions in the inner ear. However, less is known of thyroid hormone functions in the middle ear, which contains the ossicles (malleus, incus, stapes) that relay mechanical sound vibrations from the outer ear to the inner ear. During the later stages of middle ear development, prior to the onset of hearing, middle ear cavitation occurs, involving clearance of mesenchyme from the middle ear cavity while the immature cartilaginous ossicles attain appropriate size and ossify. Using in situ hybridization, we detected expression of Thra and Thrb genes encoding thyroid hormone receptors alpha1 and beta (TRalpha1 and TRbeta, respectively) in the immature ossicles, surrounding mesenchyme and tympanic membrane in the mouse. Thra(+/PV) mice that express a dominant-negative TRalpha1 protein exhibited deafness with elevated auditory thresholds and a range of middle ear abnormalities including chronic persistence of mesenchyme in the middle ear into adulthood, markedly enlarged ossicles, and delayed ossification of the ossicles. Congenitally hypothyroid Tshr(-/-) mice and TR-deficient Thra1(-/-);Thrb(-/-) mice displayed similar abnormalities. These findings demonstrate that middle ear maturation is TR dependent and suggest that the middle ear is a sensitive target for thyroid hormone in development. |
