Infrared Spectral Imaging Analysis Of Cartilage Repair Tissue

Abstract

Articular cartilage is a homogenous tissue that provides frictionless movement between joints while withstanding repetitive physical stress. Once degenerated as a result of osteoarthritis or an injury, it has very limited capacity for self-repair. Recent research has focused on developing many new technologies for cartilage repair. The successful application of these strategies is limited in part to lack of techniques to evaluate tissue response to interventions. Assessment of the structural and molecular changes in the primary cartilage components, proteoglycan (PG) and collagen is critical to evaluate progress of the repair tissue. In the present study Fourier transform infrared imaging spectroscopy (FT-IRIS) was utilized to evaluate molecular changes in normal and degenerated cartilage in a rabbit model of repair. Parameters such as collagen integrity, type II collagen and proteoglycan are important factors in determining the biomechanical properties of articular cartilage, and are likely as important in determining functional competence of repair tissue. Histological evaluations are considered to be one of the most important methods for determining the quality of the repair tissue, but still do not predict clinical outcome. It is possible that a new tissue scoring system that considers molecular parameters in the repair tissue, along with the histological outcomes, will better predict clinical success of repair. The main goal of this study is to assess correlations between histological grading, immunohistochemical assessments of type I and II collagen, and FT-IRIS parameters, in cartilage repair tissue in a rabbit model. These data will provide the basis for a novel tissue scoring system using FT-IRIS parameters alone, or in conjunction with histological and immunohistochemical outcomes. This could yield better correlations with clinical outcomes that may lead to optimization of the cartilage repair process.