In vitro conditions affecting the synthesis of sulfated proteoglycans by normal and rheumatoid synovial cells in culture

Abstract

In vitro conditions affecting synthesis of sulfated proteoglycans by cell suspensions derived from monolayer cell cultures of normal and rheumatoid synovial tissue were examined. The capacity of cells to synthesize proteoglycans was estimated by the incorporation of 35sSulfate into cetylpyridinium chloride-precipitable material. Synthesis of sulfated proteoglycans was maximal during log phase, and after 2-3 hours of recovery from disaggregation. Normal synovial cells appeared to be more sensitive to changes in serum concentration than were rheumatoid synovial cells, but rheumatoid synovial cells were more sensitive to changes in cell density. The proportion of newly synthesized extracellular proteoglycans increased with the duration of incubation in 3 5~u~f a t e . Synthesis of sulfated proteoglycans by human synovial cells has recently been demonstrated by several techniques, including the incorporation of "Ssulfate into cetylpyridinium chloride (CPC)-precipitable material (1-5). Synthesis of sulfated proteoglycans by normal and rheumatoid synovial cell lines in longterm culture was influenced by repeated passage of the