Fig. 4

Gross anatomy outcome was assessed by visual examination of joint surfaces. a Representative images of the macroscopic appearance of the articular cartilage surface in one animal from each group (control, MSC-naïve, MSC-primed) at both end-points (two and six months). Assigned scores in these images were 3 (control, both 2 and 6 months), 0 (MSC-naïve, 2 months), 1 (MSC-naïve, 6 months; MSC-primed, 2 months) and 2 (MSC primed, 6 months). b Mean ± SEM of the gross anatomy score for each group at two months end-point (phase 2 lesion, light grey bars; control, n = 4 radio-carpal [RC]-joints; MSC-naïve, n = 7 RC-joints; MSC-primed, n = 7 RC-joints) and at six months end-point (phase 1 lesion, dark grey bars; control, n = 4 RC-joints; MSC-naïve, n = 7 RC-joints; MSC-primed, n = 7 RC-joints). The highest possible score is 4. (* = p < 0.05)