Fig. 1.

Study design. A cartilage defect was created surgically (✸) in the right knee of twelve rabbits, 7 days prior to intra-articular injection of MSCs. Labeled integrin ⍺10-MSCs (▲, rabbit 1–8) or DMSO freezing medium (▼, rabbit 9–12) was injected into the right knee at time 0. Baseline MRI scans (●) of the injected knee of rabbits 1–6 were performed on day-3 (4 days after surgery), while rabbits 7–12 did not undergo MRI scanning, but had their knees harvested for histology. Additional MRI scans were conducted immediately after injection of MSCs (0 h) and 12 h, 24 h, 2 days, 4 days, 7 days and/or 10 days after MSCs injection (2–6 rabbits scanned at each time point). Osteochondral tissue samples of the defect area were collected for histology and immunofluorescence analysis after euthanasia (➕) from both treated and control rabbits. ^§Rabbit 3 was removed from the study because of unintentional peri-articular injection of labeled ⍺10-MSCs