Isolation of proliferating chondrocytes from bovine growth-plate cartilage by rate-zonal centrifugation in a Ficoll density gradient.

UNLABELLED

A method has been developed for the isolation of growth-plate chondrocytes with different biochemical properties by rate-zonal centrifugation in a Ficoll density gradient. Bovine calf growth plates were first incubated in F-12 medium in the presence of 3H-thymidine to label proliferating chondrocytes. The tissue was then digested with collagenase and the isolated cells were fractionated in a Ficoll density gradient. The chondrocytes, which sedimented into eleven fractions, were analyzed for 3H-thymidine and inorganic pyrophosphatase activity. Chondrocytes that were maximally labeled with 3H-thymidine and contained maximum pyrophosphatase contents were separated in the most dense, bottom fractions of the gradient. These chondrocytes, which were apparently derived from the zone of proliferating chondrocytes, remained viable. This procedure should be applicable to the study of the biochemical properties of chondrocytes from the different zones of normal and diseased growth plates.

CLINICAL RELEVANCE

A procedure has been developed to separate proliferating chondrocytes from hypertrophic chondrocytes and to isolate the proliferating chondrocytes in a viable state. This procedure should make it possible to study in vitro some of te biochemical processes that are involved in normal endochondral ossification, the regulation of these processes, and the alterations that occur in these processes in the presence of growth disorders and disturbances in endochondral ossification.