Fig. 8

Fluorescence analysis of labeled integrin α10-MSCs and cartilage specific molecules aggrecan, collagen type II (COL2) and integrin α10. Osteochondral sections obtained after euthanasia from rabbits with a surgically created and partially healed cartilage defect (4–10 days after intra-articular injection of either MIRB-labeled integrin α10-MSCs or from untreated rabbits). MIRB-labeled integrin α10-MSCs are detected in the cartilage repair tissue of treated rabbits (red, C–F). The cartilage specific molecules aggrecan (green, A–D), COL2 (green, F), and integrin α10 (green, E) are stained with specific antibodies, and cell nuclei are stained with DAPI (blue, A–F). A Normal undamaged cartilage from a treated rabbit (rabbit #1) showing aggrecan (green) in chondrocytes and in the extracellular matrix. B Repair tissue in an untreated cartilage defect (rabbit #10 euthanized on day 10) showing aggrecan (green). C Repair tissue in a treated cartilage defect (rabbit #4 euthanized on day 10) showing MIRB-labeled integrin α10-MSCs (red) and aggrecan (green). D MIRB-labeled integrin α10-MSCs co-localizes with aggrecan, which is seen as cells with both red and green stain (white arrows) as well as red cells surrounded by green aggrecan-containing extracellular matrix. E MIRB-labeled integrin α10-MSCs co-localizes with collagen type II, which is mainly seen as cells with both red and green stain (arrow). F The collagen-binding receptor integrin α10 (green) is expressed on both MIRB-labeled α10-MSCs (red) and resident chondrocytes. Co-localization of MIRB-labeled α10-MSCs and integrin α10 is seen as cells expressing both red and green (white arrows). MIRB Molday Ion conjugated with Rhodamine B