Regeneration of articular disc defects and osteochondral surface caused by osteoarthritis in the temporomandibular joint

Abstract

The temporomandibular joint (TMJ) articular disc presents scarce vascularization which makes it difficult to repair. The objective of this study is to evaluate the effect of hyaluronic acid hydrogel associated with mesenchymal stem cells derived from bone marrow (BM-MSCs), with chondrogenic differentiation (CBM-MSCs), in the regeneration of the articular disc and osteochondral surface of the TMJ. Osteoarthritis will be induced by means of bilateral perforation of the articular disc of rabbits. BM-MSCs will be isolated from the bone marrow of the tibia of each animal for subsequent chondrogenic differentiation and incorporation into hydrogel. Viability, cell adhesion, proliferation and differentiation tests will be performed in cultured cells, before and after incorporation into hydrogel. Forty rabbits will be divided into 4 groups: G1 (lesion/hyaluronic acid hydrogel + CBM-MSCs), G2 (lesion/hyaluronic acid hydrogel), G3 (lesion//no treatment), G4 (no lesion/no treatment). The groups G1, G2 and G3 will be composed of 12 animals, and G4 of 4 animals. After 4 weeks of articular disc perforation, rabbits from the groups G1 and G2 will be treated, as men articular disc mentioned above. After periods of 4 and 24 weeks, 6 animals will be euthanized in G1, G2 and G3 groups and 2 in the G4 group. The articular disc will be evaluated radiographically to identify possible calcifications. Macroscopic analysis of the articular disk and mandibular condyle will be made as well as histological analysis to evaluate the tissue architecture, the arrangement of cells and the presence of inflammation. Immunohistochemical expression of collagen I and II, aggrecan and SOX9 will be evaluated to establish the type of tissue. The results will be statistically evaluated, adopting the significance level of 5%. (AU)