Immunohistochemical detection and immunochemical analysis of type II collagen degradation in human normal, rheumatoid, and osteoarthritic articular cartilages and in explants of bovine articular cartilage cultured with interleukin 1.

Abstract

Articular cartilage destruction and loss of function in arthritic diseases involves proteolytic degradation of the connective tissue matrix. We have investigated the degradation of cartilage collagen by developing immunochemical methods that permit the identification and analysis of type II collagen degradation in situ. Previously, a technique to specifically identify type II collagen degradation in situ in articular cartilage did not exist. These methods utilize a polyclonal antiserum (R181) that specifically reacts with unwound a-chains and CNBr-derived peptides, al(II)CB11 and al(II)CB8, of human and bovine type II collagens. The experimental approach is based on the fact that when fibrillar collagens are cleaved the helical collagen molecule unwinds, exposing hidden epitopes. Here we demonstrate the use of R181 in studying type II collagen degradation in bovine articular cartilage that has been cultured with or without IL-1 and in human normal, rheumatoid, and osteoarthritic articular cartilages. Compared to cartilages either freshly isolated or cultured without IL-1, bovine cartilage cultured with IL-1 for 3-5 d showed an increase in both pericellular and intercellular immunohistochemical staining. Extracts of these cartilages contained type II collagen a chains that were increased in amount after culture with IL-1 for 11 d. In addition, culture with IL-1 resulted in the appearance of a chain fragments of lower molecular weight. All human arthritic tissues examined showed areas of pronounced pericellular and territorial staining for collagen degradation as compared with nondiseased tissues, indicating that chondrocytes are responsible in part for this degradation as compared with nondiseased tissues. In most cases rheumatoid cartilage was stained most intensely at the articular surface and in the deep and midzones, whereas osteoarthritic cartilage usually stained more in the superficial and mid-zones, but less intensely. Distinct patterns of sites of collagen degradation reflect differences in collagen destruction in these diseases, suggesting possible different sources of chondrocyte activation. These experiments demonstrate the application of immunological methods to detect collagen degradation and demonstrate an increase of collagen degradation in human arthritides and in IL-1-treated viable bovine cartilage.

A correlation between knee cartilage degradation observed by arthroscopy and synovial proteinases activities

“…Under conditions which accompany inflammatory joint disorders and changes in the composition of its extra-cellular matrix, chondrocytes undergo significant alterations which are not yet fully understood [3,[31][32][33][34]. Therefore, we focused our interest on the behavior of some molecules, such as MMPs and TIMPs, which are proposed to be active agents during joint degeneration processes.…”

Suppression of cartilage matrix gene expression in upper zone chondrocytes of osteoarthritic cartilage

“…In OA cartilage, damage to the collagen network and loss of aggrecan are functionally deleterious (31,32). Chondrocytes attempt to repair the damaged matrix by increasing the synthesis of both of these main components (9,13,14,20,33,34).…”

Early changes in serum type ii collagen biomarkers predict radiographic progression at one year in inflammatory arthritis patients after biologic therapy

“…Type II collagen (CII) is the main collagen of articular cartilage, and CII is excessively degraded in RA, PsA, and osteoarthritis (OA) (20)(21)(22)(23)(24)(25), an effect believed to result from its cleavage by collagenases. Cleavage of the triple helix of CII by collagenase exposes a helical neoepitope Col2-3/4C long mono (C2C), which can be detected by immunoassay (26)(27)(28).…”