Platelet-Rich Plasma Loaded Alginate-Based Injectable Hydrogel for Meniscal Tear Repair: In Vivo Evaluation in Lapine Model.

Platelet-rich plasma (PRP) has been employed for orthopedic applications for decades due to the abundance of bioactive cues/growth factors that ameliorate the proliferation and migration of relevant cells involved in tissue repair/regeneration. In this work, PRP was incorporated into injectable compositions of alginate-based hydrogel and evaluated in vitro and in vivo. In vitro tests revealed that PRP addition promoted cell adhesion, cell proliferation, and distribution of seeded fibrochondrocytes on the hydrogel. Further, the DNA quantification and sGAG estimation confirmed the production of fibrocartilage-specific extracellular matrix, predominantly type 1 collagen and sGAG. For in vivo evaluation, tears were created surgically in the rabbit menisci and were filled with injectable hydrogel. Sham and hydrogel without PRP were used as controls. Histopathological evaluation after 3 months of implantation revealed that the healing was partial for sham control, but complete for hydrogel without PRP. The hydrogel served as the scaffold for fibrocartilage tissue regeneration. On the other hand, PRP-incorporated hydrogel showed good healing with low signs of inflammation as evidenced by histology and biochemical content. The healing was complete, and the nature of the regenerated tissues was very close to native tissue indicating that alginate-based hydrogel is a promising candidate for meniscal tissue repair.