Pretreatment of periosteum with TGF-β1 in situ enhances the quality of osteochondral tissue regenerated from transplanted periosteal grafts in adult rabbits  A. Olivos-Meza, J.S. Fitzsimmons, M.E. Casper, Q. Chen, K.-N. An, T.J. Ruesink, S.W. O’Driscoll, G.G. Reinholz  Osteoarthritis and Cartilage  Volume 18, Issue 9, Pages 1183-1191 (September 2010) DOI: 10.1016/j.joca.2010.06.003 Copyright © 2010 Osteoarthritis Research Society International Terms and Conditions

Fig. 1 An osteochondral transverse defect, measuring 5mm proximal to distal and spanning the entire width of the patellar groove, was created using a scalpel and a conventional jewelry saw. Measurements of all areas in the defects were done with a Vernier caliper. In contrast to the original contour of the patellar groove, the base of the defect was flattened with a 5mm wide file and was approximately 2mm below the surface of the middle of the patellar groove. Osteoarthritis and Cartilage 2010 18, 1183-1191DOI: (10.1016/j.joca.2010.06.003) Copyright © 2010 Osteoarthritis Research Society International Terms and Conditions

Fig. 2 Safranin O/fast green stained histological sections (A–C) and corresponding gross images (D–F) of defects repaired with untreated periosteum (A & D), TGF-β1-pretreated periosteum (B & E), and contralateral controls (C & F). The specimens are typical for each group at 6-weeks post-op. Improvements in the structural characteristics and bone regeneration in the TGF-β1-pretreatment group (B) compared to the untreated periosteum group (A) are clearly visible. Osteoarthritis and Cartilage 2010 18, 1183-1191DOI: (10.1016/j.joca.2010.06.003) Copyright © 2010 Osteoarthritis Research Society International Terms and Conditions

Fig. 3 Higher magnification images of Safranin O/fast green stained histological sections of the articular surfaces (A and B) and the base of the defects (C and D) from osteochondral defects repaired with untreated (A and C) and TGF-β1-pretreated periosteum (B and D) and histological scores at 6-weeks post-op. *Histological scores for cartilage structural characteristics (P=0.0002) and total bone (P=0.003), and the total histological scores (P=0.0001) for the TGF-β1-pretreatment group were significantly higher than the untreated control group based on post-hoc testing using least squares means differences Student’s t test. However, the scores for both of the defect repair groups were significantly lower than the contralateral controls. The scores are the mean values from three blinded observers. The data presented are means with 95% CI (n=9). Osteoarthritis and Cartilage 2010 18, 1183-1191DOI: (10.1016/j.joca.2010.06.003) Copyright © 2010 Osteoarthritis Research Society International Terms and Conditions

Fig. 4 Representative H & E stained histological sections of regenerated periosteum from the untreated (A) and TGF-β1-pretreated (B) periosteal graft harvest sites 6 weeks after graft harvest. The periosteal tissue was regenerated in both groups, however, the cambium layer in the regenerated periosteum from the TGF-β1-pretreatment group was significantly thicker than the untreated group (P=0.0065), based on post-hoc testing using least squares means differences Student’s t test. The cambium layers are between the yellow lines, with the bone on the bottom and the fibrous layer on the top in panels A & B. The data presented are means with 95% CI (n=9 or 10). Osteoarthritis and Cartilage 2010 18, 1183-1191DOI: (10.1016/j.joca.2010.06.003) Copyright © 2010 Osteoarthritis Research Society International Terms and Conditions