Local hyperthermia and cartilage breakdown: histochemical and metabolic studies on rabbit articular cartilage in vitro.

The hypothesis that local hyperthermia generated in inflamed joints may cause damage to the articular cartilage was tested in vitro using histochemical and isotopic methods. We found that this could be the case. Incubation temperatures above 38 degrees C in experiments of longer duration and 39 degrees C during shorter incubation times induced a loss of metachromasia, decreased rates of synthesis, and increased degradation of cartilage matrix macromolecules. It is postulated that local synovial hyperthermia might partly account for the cartilage degeneration that frequently occurs in rheumatoid arthritis as a result of a decreased synthesis and increased catabolism of matrix macromolecules.