COMPUTER-BASED TECHNIQUE FOR CELL-AGGREGATION ANALYSIS AND CELL-AGGREGATION IN IN-VITRO CHONDROGENESIS

No quantitative methods are currently available to measure different a ggregation parameters in cell cultures. In this paper we describe a co mputer-based technique for the automatic and reliable analysis of cell ular aggregates, starting from optical microscopy images of living cel ls grown in suspension. The method allows determination, on the same s ample at different time intervals, of quantitative parameters, includi ng aggregation percentage, average number of cells in aggregates, and aggregate size statistical distribution. To determine the number of ce lls in an aggregate starting from its two-dimensional microscopic prof ile, a model has been proposed and verified, using sphere packing theo ry. Algorithms have been tested on chondrocyte suspension cultures, wh ere cell aggregation is a very early and critical event leading to cel l differentiation Using this technique for the analysis of chick embry o chondrocyte cultures, we observed that aggregate size and developmen t kinetics depend on the culture conditions used, The method, with min or adaptations, is of potential use also in other cell systems to eval uate aggregation indexes or to study aggregation kinetics. (C) 1997 Wi ley-Liss, Inc.