Biochemical and metabolic abnormalities in articular cartilage from osteo-arthritic human hips. II: Correlation of morphology with biochemical and metabolic data

Abstract

Thirty-two areas of cartilage from nine osteoarthritic and four normal femoral heads were studied and their severity of osteoarthtic process was graded using a histologic-histochemical grade. Their DNA and hexosamine concentrations were used as indicators of cell density and polysaccharide content, respectively, and the incorporation rates of 3H-thymidine and 35SO 4 were assessed as indicators of DNA and polysaccharide synthesis, respectively. Based on these measurements and subsequent analyses, the following conclusions were made: 1. Osteoarthritis is a focal disease with substantial variation in the severity of the lesion on each osteoarthritic femoral head. 2. The severity of the process and the rates of DNA and polysaccharide synthesis are directly correlated. However at a certain histologic-histochemical degree of "severity," the reparative processes seem to "fail," decreasing with advancing disease. 3. The severity of the process and the polysaccharide concentration are inversely correlated, but the cell density (as refl ected by DNA levels) and the severity of the disease do not correlate. 4. The cartilage of osteophytes is histologically less severely involved showing a smaller reduction in polysaccharide concentrations. Polysaccharide synthesis at osteophytes is increased as compared with non-osteophytic arthritic tissue. On the basis of the above data, a scheme of the biochemical and metabolic response of cartilage to osteo-arthritis is suggested.