Fig. 8.

Chondrocytes (hAC), ASC/TERT1 or bone marrow cells in the incisions of decell-deGAG treated scaffolds with laser-engraved grid patterns in vivo. (Immuno-)Histochemistry shows a a) regular distribution of cells inside the incisions and b) newly synthesized matrix. Human chondrocyte-derived matrix displays a gradient of increasing staining intensity of collagen type II (Coll2=brown in single-staining) within the incisions (tip effect) and a dominance of collagen type II staining over collagen type I in the double staining (Coll2=pink, Coll1=brown in double-staining). A gradient towards the tip is also visible for GAG in Alcian blue staining. In the ASC/TERT1-seeded scaffolds collagen type II is found along the whole incision with slightly increasing density towards the tip but still generally weaker staining in comparison to the chondrocyte group. Also in the double staining collagen type I is more dominant (brown instead of red in Coll1/Coll2 double staining) and the GAG-staining faint (Alcian blue). Matrix derived from invaded bone marrow cells stains regularly and strong for collagen type II without any visible collagen type I staining (only pink Coll1/Coll2 double staining) and strong GAG (Alcian blue) staining. In all groups some cells invaded empty lacunae inside the scaffold matrix (arrows). c) Staining of CD68 positive cells (arrows) indicates the presence of macrophages in the ASC/TERT1 and hAC group but not in the dense, bone-marrow involving neo-cartilage. n = 6. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)