Phenotype-Preserving Co-culture of Osteoblasts and Chondrocytes Enhances Bone-Cartilage Interface Integration in a PRP-Augmented Scaffold.

Background: Effective bone-cartilage integration remains a challenge in orthopedic surgery. Conventional methods often fail to reconstruct the native osteochondral interface. This study explores a scaffold-mediated approach utilizing co-cultured osteoblasts and chondrocytes, with platelet-rich plasma (PRP) as a potential promotor for bone-cartilage interface healing.

Methods: We developed a co-culture system integrating both osteoblasts and chondrocytes on PLGA scaffolds, either with or without PRP supplementation. Cell phenotype maintenance was evaluated by RT-PCR, while morphological analysis was performed by scanning electron microscopy and fluorescence microscopy. To assess healing potential, we created a gap-mimic construct comprising bone, scaffold, and cartilage layers, which was implanted subcutaneously in BALB/c-nude mice. Gap healing was evaluated at 4 and 8 weeks through macroscopic examination, quantitative adhesion analysis, and histological assessment of cellular invasion.

Results: Co-cultured osteoblasts and chondrocytes maintained their phenotypes on PLGA scaffolds, with PRP significantly enhancing cell adhesion (215% increase for chondrocytes, 120% for osteoblasts) and proliferation. In vivo, cell-containing scaffolds demonstrated significantly greater attachment at the bone-cartilage interface compared to acellular constructs. PRP-treated scaffolds exhibited higher attachment rates (82.3% vs 76.7%) and cellular invasion (5/6 vs 3/6 constructs) at 8 weeks, with invasion observed as early as 4 weeks in the PRP group, suggesting accelerated remodeling.

Conclusion: This study demonstrates the feasibility of developing transplantable scaffolds containing co-cultured osteoblasts and chondrocytes while preserving their phenotypes. These scaffolds exhibit significant potential in promoting healing at the bone-cartilage interface, with PRP further enhancing proliferation and improving the scaffold's ability to promote bone-cartilage interface healing.