The effect of melatonin and vitamin C treatment on the experimentally induced tympanosclerosis: study in rats

[Advances in research on treatment of tympanosclerosis]

Tympanosclerosis is the hyaline degeneration and calcium deposition of the lamina propria of tympanic membrane and the submucosa of middle ear under long-term chronic inflammatory stimulation. At present, treatment primarily involves the surgical removal of sclerotic foci and reconstruction of auditory ossicular chain. However, excision of sclerotic lesions near critical structures like the facial nerve canal and vestibular window may result in complications like facial paralysis, vertigo, and sensorineural hearing loss. Developing safer and more effective treatments for tympanosclerosis has become an international research focus. Recent years have seen novel explorations in the treatment of tympanosclerosis. Therefore, this article reviews the latest advancements in research on the treatment of tympanosclerosis.

Role of TGF-β1-mediated epithelial-mesenchymal transition in the pathogenesis of tympanosclerosis

The present study aimed to explore the role of TGF-β1-mediated epithelial-mesenchymal transition (EMT) in the pathogenesis of tympanosclerosis. Sprague Dawley rats were injected with inactivated Streptococcus pneumoniae suspension to establish a rat model of tympanosclerosis. The rats were sacrificed 8 weeks after the model was established. H&E and von Kossa staining was used to observe the morphological changes of middle ear mucosa. Western blotting was used to detect the expression of TGF-β1 and EMT-associated proteins in the mucosa samples. Middle ear mucosal epithelial cells of rats were collected to establish a primary culture. The cultured cells were stimulated with TGF-β1 and the expression of EMT-associated proteins was detected by western blotting and immunofluorescence. In addition, the cells were treated with TGF-β receptor type I/II inhibitor and the expression level of EMT-associated proteins was detected by western blotting. Sclerotic lesions appeared on 72.4% of tympanic membranes, and marked inflammation, inflammatory cell infiltration and fibrosis were found in the middle ear mucosa of rat models of tympanosclerosis. In middle ear mucosa of rats with tympanosclerosis, the expression of mesenchymal cell markers increased and that of epithelial cell markers decreased compared with the control group. TGF-β1 stimulated the activation of the EMT pathway in middle ear mucosal epithelial cells, resulting in an increased expression of fibronectin and N-cadherin. In addition, a decreased expression level of EMT-associated proteins was observed when TGF-β1 was inhibited. In conclusion, the present study indicated that TGF-β1-mediated EMT may play an important role in the pathogenesis of tympanosclerosis.