To study the effects of intermittent loading on the proteoglycans synthesized in intact cultured articular cartilage.
Sesamoid bones carrying articular cartilage were subjected to cyclic loading in vitro for one week. A new procedure to fix and decalcify the tissue was developed and an immunohistochemical analysis of the expression of 3-B-3(-) epitope in the articular cartilage was carried out. The proteoglycans synthesized were quantified and studied using CL-2B chromatography.
Loading induced an increase in the synthesis of aggrecan molecules, which were larger and less polydisperse than those from control cartilage. Loading also induced the expression of 3-B-3(-) epitopes on newly synthesized proteoglycans.
These changes are similar to those found in early experimental and human osteoarthritis (OA). More variables must be studied, but our results suggest that our model might be suitable to study early events in the onset of OA.