Characterization of the meniscus for future tissue engineering efforts
Sweigart, Mark Andrew
Athanasiou, Kyriacos A.
Doctor of Philosophy
The meniscus, a fibrocartilagenous tissue found between the femur and tibia, is responsible for shock absorption, load transmission, and stability within the knee joint. Damage to this tissue can lead to osteoarthritic changes, suggesting that the meniscus protects the knee joint from degenerative joint disease. Historically, repair techniques consisted of excision or suturing of the damaged tissue. Unfortunately, neither of these techniques successfully repairs the damaged tissue; tissue engineering is one possible solution. When attempting to tissue engineer a tissue, it is ideal to start in a small animal model, such as a rabbit, before attempting the repair process in a larger animal model. The objective of this work was to characterize the medial rabbit meniscus ultrastructurally, biomechanically, biochemically, and cellularly and to perform biomechanical characterization on larger animal models for future scale up efforts. The medial rabbit meniscus was found to have a higher hydration level, greater amount of sulfated glycosaminoglycans, and lower level of hydroxyproline at the inner 1/3 of the tissue, which confirmed the more chondrocytic nature of this region. It was also found that the anterior portion of the tissue, particularly in the inner 1/3, had a higher hydration level, sulfated glycosaminoglycan level, aggregate modulus, permeability, shear modulus, and a lower hydroxyproline level than the central and posterior locations. It is believed that this topographical variation is due to the bent-knee resting stance of the rabbit and its propensity to jump. It was also determined that significant variations exist in the compressive creep properties, both intraspecies and interspecies, in a variety of animal models, indicating caution when comparing animal models and determining which animal model to use in future tissue engineering efforts. The characterization in this study can serve as a "gold standard" reference for future meniscal tissue engineering efforts and be used as a baseline for future large animal tissue engineering efforts.