Quercetin-Loaded Zeolitic Imidazolate Framework-8 (ZIF-8) Nanoparticles Attenuate Osteoarthritis by Activating Autophagy via the Pi3k/Akt Signaling

Osteoarthritis treatment remains a significant clinical challenge. Quercetin, a natural flavonoid with anti-inflammatory and antiapoptotic properties, might be utilized to treat OA. However, poor water solubility and short joint retention duration limit its bioavailability and translation to clinical applications. A one-step self-assembly method was utilized to fabricate quercetin-loaded zeolitic imidazolate framework-8 (Qu@ZIF-8) nanoparticles using zinc ions, 2-methylimidazole, and quercetin. In vitro tests showed that Qu@ZIF-8 nanoparticles released pH-responsive agents into chondrocytes, effectively protecting them from interleukin (IL)-induced inflammation and apoptosis, thereby promoting cartilage anabolic activities. These underlying mechanisms revealed a remarkable increase of autophagy in IL-β-treated chondrocytes, followed by the inhibition of the Pi3k/Akt signaling pathway, which contributed to the protective effect of Qu @ZIF-8. By the establishment of medial meniscus instability (DMM) in OA mice, Qu@ZIF-8 substantially improved cartilage structural integrity and chondrocyte status, as well as attenuated OA progression. Importantly, Qu@ZIF-8 outperformed quercetin alone in the treatment of OA due to its control release. The combined research findings indicate that Qu@ZIF-8 shields chondrocytes from inflammation and apoptosis by activating autophagy and repressing the Pi3k/Akt pathway. This investigation may provide new insights for clinically extending the therapy of OA.