Culture of synovial cells in vitro. Notes on isolation and propagation.

The culture of synovial cells in vitro provides a useful means for the study of connective tissue function. Vaubel (1933) first used cultures of synovium to show that mucin was secreted in the joint itself, a conclusion since confirmed by others (Kling, Levine, and Wise, 1955; Castor, 1957; Hedberg and Moritz, 1958; Fischer and Torgerson, 1960). In recent years, Castor has studied synovial culture extensively in a variety of aspects (Castor, 1959, 1960, 1962; Castor and Fries, 1961; Castor and Prince, 1963). In all these studies synovial culture has relied on the growth of cells from pieces of synovium, or "explants". In a preliminary report (Fraser and Catt, 1961), we described an alternative method for the harvest of synovial intima in a monocellular suspension suitable for culture. This paper records our further experience with the initial isolation of synovial cells, and their serial propagation beyond the stage of primary culture. Evidence is also presented to show that the new method is more likely to yield cells derived solely from the synovial intima. Certain aspects concerned with specific experimental applications will be reported in detail later.