The effect of adipose-derived mesenchymal stem cells and chondrocytes with platelet-rich fibrin releasates augmentation by intra-articular injection on acute osteochondral defects in a rabbit model

Background: This study aimed to investigate the efficacy of adipose-derived mesenchymal stem cells (ADSCs), platelet-rich fibrin releasates (PRFr), and chondrocyte transplantation in rabbit acute osteochondral defects. Methods: Thirty rabbits were randomly assigned to five groups: untreated controls; ADSCs alone; PRFr alone; PRFr + ADSCs; and PRFr + chondrocytes. The critical size osteochondral defects in right knee femoral condyles were injected intra-articularly according to the groups, as listed. The experimental rabbits received treatments once a week for two weeks postoperatively. All evaluations were conducted for 14 weeks following surgery, and the regenerated cartilages were assessed by gross inspection and histological examination. Results: There were no complications encountered in any of the rabbits. The size of the defect decreased and the volume of repaired cartilage increased in the medial femoral condyles of the PRFr + ADSCs group. Relative to the ADSCs or PRFr group, histological examination demonstrated that the PRFr + ADSCs group had thicker hyaline cartilage-specific extracellular matrix. Grading scores revealed that PRFr + ADSCs injection had better matrix, cell distribution, and surface indices than other groups (P < 0.05). However, the histological scores reported for PRFr + chondrocytes on cartilage repair were similar to those of PRFr, and there were no significant between-group differences. Conclusions: These findings showed that intra-articular injections of PRFr + ADSCs into the knee can reduce cartilage defects by regenerating hyaline-like cartilage without complications. This approach may provide an alternative method for functional reconstruction of acute osteochondral defects with an unlimited source of cells and releasates.