Exosomes derived from platelet-rich plasma present a novel potential in repairing knee articular cartilage defect combined with cyclic peptide-modified β-TCP scaffold.

Background: The aim of this study was to investigate the therapeutic effects and mechanisms of PRP-exos combined with cyclic peptide-modified β-TCP scaffold in the treatment of rabbit knee cartilage defect.

Methods: PRP-exos were extracted and characterized by TEM, NTA and WB. The therapeutic effects were evaluated by ICRS score, HE staining, Immunohistochemistry, qRT-PCR and ELISA. The repair mechanism of PRP-exos was estimated and predicted by miRNA sequencing analysis and protein-protein interaction network analysis.

Results: The results showed that PRP-exos had a reasonable size distribution and exhibited typical exosome morphology. The combination of PRP-exos and cyclic peptide-modified β-TCP scaffold improved ICRS score and the expression level of COL-2, RUNX2, and SOX9. Moreover, this combination therapy reduced the level of MMP-3, TNF-α, IL-1β, and IL-6, while increasing the level of TIMP-1. In PRP-exos miRNA sequencing analysis, the total number of known miRNAs aligned across all samples was 252, and a total of 91 differentially expressed miRNAs were detected. The results of KEGG enrichment analysis and the protein-protein interaction network analysis indicated that the PI3K/AKT signaling pathway could impact the function of chondrocytes by regulating key transcription factors to repair cartilage defect.

Conclusion: PRP-exos combined with cyclic peptide-modified β-TCP scaffold effectively promoted cartilage repair and improved chondrocyte function in rabbit knee cartilage defect. Based on the analysis and prediction of PRP-exos miRNAs sequencing, PI3K/AKT signaling pathway may contribute to the therapeutic effect. These findings provide experimental evidence for the application of PRP-exos in the treatment of cartilage defect.