Injectable Self-Assembling Procyanidin Nanospheres for Effective Osteoarthritis Treatment

Background: Osteoarthritis (OA), a prevalent joint disease, causes immense suffering to thousands of patients, impairing their mobility and diminishing their quality of life. Current treatment methods primarily rely on analgesics or anti-inflammatory drugs to alleviate symptoms but fail to achieve the desired therapeutic outcome. Methods: To better realize therapeutic effects of OA, procyanidins (PAs), as a type of plant flavonoids with strong antioxidant and anti-inflammatory activities, were designed to self-assembly with well-dispersible Pluronic F127 (PF127) through the hydrogenbond interaction to present an injectable, biocompatibility PA nanospheres. Results: These nanospheres significantly increased the cell viability in mouse L929 fibroblasts and ADTC5 chondrocytes compared with unassembled PAs. In addition, the self-assembling PAs/PF127 nanospheres enhanced the protein expression of collagen (COL1A1 and COL3A1) in fibroblasts, and the expression of glycosaminoglycan and COL2A1 was also higher than unassembled PAs in chondrocytes, this heralded the potential to achieve OA repair strategies at the cellular level. In an enzymolysis model of rat OA, PAs/PF127 nanospheres significantly reduce joint space swelling in the early stages of cartilage destruction and accelerate the formation of subchondral bone and cartilaginous surface. Implication: This study offers valuable insights into the preparation of novel PA nanospheres for effective repair of OA.