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  • Development of tissue-engineered temporomandibular discs based on xenogeneic extracellular matrices
    Publication . Trindade, Daniela Alexandra Pinheiro; Moura, Carla Sofia Monteiro de; Calado, Cecília Ribeiro da Cruz
    The temporomandibular joint (TMJ) disc is a fibrocartilaginous tissue that supports and lubricates the joint. Due to this important feature and the fact that presents low intrinsic regeneration capacity, is highly predisposed to suffering traumatic injuries or degeneration, including all structures of the joint. In more advanced cases of disc dysfunction, its total removal is essential to decrease pain and increase oral function. However, a substitute is needed for joint stabilization, correct dental occlusion and to prevent degeneration in the remaining bone structures. Some attempts in the field of tissue engineering to find a suitable substitute have been done, but the research persists. Interest in decellularized xenogeneic tissues has been increasing, so the present study has focused on developing a potential TMJ disc based on the decellularization of lamb discs. To this end, different decellularization protocols were evaluated by testing different agents/concentrations, such as solvents (ethanol/acetone), detergents (sodium dodecyl sulfate and Triton X-100) and enzymes (accutase). A physical method (one cycle of freeze and thaw) was also combined with the two detergents. A complete analysis of the morphology (weight, thickness and mediolateral and anteroposterior dimensions) and compression tests of the native and acellular discs were performed to evaluate if there were changes in the properties of the disc. Univariate and multivariate analyses by Fourier transform infrared spectroscopy were applied to assess the impact of the decellularization agents on the extracellular matrix (ECM) components, such as collagen and glycosaminoglycans (GAGs). Moreover, scanning electron microscope and micro-computed tomography allowed the visualization of the morphology of the disc, enabling the evaluation of the ECM and the removal of complete cell content. Through this thesis it was possible to carry out a preliminary study in which different methods of decellularization were evaluated, where experiments showed that the combination of freezing and thawing followed by 0.1% Triton X-100 leads to the complete cell removal, preservation of morphology and mechanical behaviour, while collagen and GAGs are minimally affected. Future studies are proposed for the optimization of this protocol such as the implementation of more freeze and thaw cycles and the combination with accutase enzyme.
    2021-06-01Master thesis Open access Show more