Effect of autologous lyophilized platelet-rich fibrin on the reconstruction of osteochondral defects in rabbits

Osteochondral defects caused by degenerative diseases of joints, traumas and inflammation are important issues in clinical practice. Different types of autologous platelet concentrate (PCs) are used in bone and cartilage regeneration. The present study aimed to investigate the effect of lyophilized platelet-rich fibrin (L-PRF) on the repair of osteochondral defects in rabbits. L-PRF was first prepared from fresh PRF (F-PRF) through freeze-drying, and histological and microstructural observations were performed to compare the characteristics of L-PRF and F-PRF. Thereafter, these bioactive scaffolds were implanted into osteochondral defects surgically created in rabbits to assess their effects on tissue repair using micro-CT scanning, histological observations and the evaluation scoring method for cartilage repair established by the International Cartilage Repair Society (ICRS). L-PRF had a histological structure similar to F-PRF. At 16 weeks after implantation surgery, full-thickness osteochondral defects with a diameter of 5 mm and a depth of 4 mm were well-filled with newly regenerated tissues, exhibiting the simultaneous regeneration of avascular articular cartilage and well-vascularized subchondral bone, as proven through macroscopic and microscopic observations in PRF-treated groups compared with that in the untreated group. The application of L-PRF and F-PRF for osteochondral defects in rabbits contributed to massive host remodeling and reconstruction of osteochondral tissues, thus offering a prospective bioactive scaffold for the simultaneous reconstruction of articular cartilage and subchondral bone tissue.