FIGURE 1.

Collagenase II from four suppliers performed similarly well with only slight differences in isolating viable chondrocytes from human articular cartilage. (A) Apoptotic and necrotic states were determined by propidium iodide (PI) and Annexin V staining of chondrocytes released from human articular cartilage tissue by digestion with collagenase II obtained from four different commercial suppliers. Representative dot plots from FACS analysis are shown. (B) Percentages of live (Annexin V− PI−), early apoptotic (Annexin V+ PI−), late apoptotic (Annexin V+ PI+), and necrotic cells (Annexin V− PI+) and total numbers of recovered cells per gram of cartilage tissue are plotted. Data were generated from two independent experiments with samples from two individual patients.