Combination of Mesenchymal Stem Cells, Cartilage Pellet and Bioscaffold Supported Cartilage Regeneration of a Full Thickness Articular Surface Defect in Rabbits.

BACKGROUND

Mesenchymal stem cells (MSCs) and/or biological scaffolds have been used to regenerate articular cartilage with variable success. In the present study we evaluated cartilage regeneration using a combination of bone marrow (BM)-MSCs, Hyalofast and/or native cartilage tissue following full thickness surgical cartilage defect in rabbits.

METHODS

Full-thickness surgical ablation of the medial-tibial cartilage was performed in New Zealand white (NZW) rabbits. Control rabbits (Group-I) received no treatment; Animals in other groups were treated as follows. Group-II: BM-MSCs (1 × 10 cells) + Hyalofast; Group-III: BMMSCs (1 × 10 cells) + cartilage pellet (CP); and Group-IV: BM-MSCs (1 × 10 cells) + Hyalofast + CP. Animals were sacrificed at 12 weeks and cartilage regeneration analyzed using histopathology, International Cartilage Repair Society (ICRS-II) score, magnetic resonance observation of cartilage repair tissue (MOCART) score and biomechanical studies.

RESULTS

Gross images showed good tissue repair (Groups IV > III > Group II) and histology demonstrated intact superficial layer, normal chondrocyte arrangement, tidemark and cartilage matrix staining (Groups III and IV) compared to the untreated control (Group I) respectively. ICRS-II score was 52.5, 65.0, 66 and 75% (Groups I-IV) and the MOCART score was 50.0, 73.75 and 76.25 (Groups II-IV) respectively. Biomechanical properties of the regenerated cartilage tissue in Group IV closed resembled that of a normal cartilage.

CONCLUSION

Hyalofast together with BM-MSCs and CP led to efficient cartilage regeneration following full thickness surgical ablation of tibial articular cartilage in rabbits. Presence of hyaluronic acid in the scaffold and native microenvironment cues probably facilitated differentiation and integration of BM-MSCs.