Fig. 5

Particulated cartilage fragments digested overnight with collagenase solution and thereafter embedded in fibrin, eosin staining, ×40 magnification. Here, we can see bone marrow-originated cells (marked with arrow) in the lower phase, under the fibrin (marked with four-point star), and over the perforated nylon membrane (in this case, it would be found to the right from the cell layer), which has detached during the sample preparation. No cell invasion after 5 weeks of cultivation