<scp>M2</scp> Macrophage‐Derived Extracellular Vehicles‐Loaded Hyaluronic Acid‐Alginate Hydrogel for Treatment of Osteoarthritis
Wen Zhang, Menghan Luo, Yi Xing, Min Wang, Wenqi Dong, Yuran Su, Xun Sun, Xinlong Ma, Qiang Yang, Yanmei Zhao, Yanhong Zhao
Abstract
OBJECTIVE: Osteoarthritis (OA), a high-prevalence degenerative cartilage disease, urgently requires novel therapeutic strategies. M2 macrophage-derived exosomes (M2-Exo) demonstrate therapeutic potential for OA, though their regulatory mechanisms in chondrocyte-macrophage (Mφ) interactions remain to be elucidated. To investigate the regulatory effects of M2-Exo on chondrocytes and Mφ in vitro, and to evaluate the therapeutic effect of the M2-Exo-loaded hydrogel system (ALG-M2Exo) on cartilage damage in a rat OA model. METHODS: In the cell experiment, M2-Exo were extracted and characterized using ultracentrifugation. Different concentrations of M2-Exo were co-cultured with inflammatory chondrocytes or M1Mφ to evaluate their direct anti-inflammatory effects and the ability to promote M1Mφ repolarization to the M2 phenotype, using methods such as EdU, TUNEL, qRT-PCR, and Western blot. Then, the repolarized RM2Mφ were co-cultured with inflammatory chondrocytes to verify their anti-inflammatory efficacy, employing similar detection methods. In the in vivo experiment, sodium iodoacetate was injected to establish a rat knee OA model, followed by interventions including ALG-M2Exo. After 4 and 8 weeks, samples were collected for gross observation and histological staining to assess cartilage damage repair. RESULTS: In the cell experiment, M2-Exo exhibited typical exosomal characteristics, directly promoting the proliferation of inflammatory chondrocytes, inhibiting their apoptosis, reducing the expression of TNF-α, iNOS, and MMP-13, and increasing the expression of IL-10 and COL II. RM2Mφ showed similar therapeutic effects on inflammatory chondrocytes as M2-Exo. In the in vivo experiment, the ALG-M2Exo group demonstrated superior repair effects on cartilage damage compared to other groups, with the treatment effect at 8 weeks being better than at 4 weeks. CONCLUSION: ALG-M2Exo effectively promotes the repair of cartilage damage in OA through both a direct pathway by releasing M2-Exo that act on chondrocytes and an indirect pathway that facilitates the repolarization of M1Mφ to M2Mφ.