Enhanced collagen deposition in chondrogenic inflammation with Ibuprofen-specifically loaded chitosan/poly-gamma-glutamic acid nanoparticles

Osteoarthritis (OA) is characterized by degeneration of articular cartilage, related to a pro-inflammatory environment. Different anti-inflammatory drugs have been proposed to treat OA symptoms, namely those from the group of non-steroidal anti-inflammatory drugs (NSAID), but they carry several drawbacks and are not able to repair/regenerate cartilage tissues. In this study, Chitosan (Ch) and Poly-Glutamic acid (PGA) were combined with Ibuprofen, a NSAID widely used in OA, for drug delivery. Ibuprofen-Ch/PGA nanoparticles (Ibuf-NPs) were produced by co-acervation method, and ability to control inflammation and promote chondrogenesis under a pro-inflammatory setting, was evaluated in vitro. To model OA, human bone marrow-derived mesenchymal stem/stromal cells (MSCs) were cultured in 3D pellets for up to 14 days in chondrogenic medium supplemented with pro-inflammatory IL-1β (10 ng/mL). Physicochemical characterization of Ibuf-Ch/PGA NPs, drug release, and anti-inflammatory potential of the Ibuf-NPs were evaluated in IL-1β-supplemented MSC pellets. Cartilage ECM was then characterized by histology/immunohistochemistry (IHC). Ibuf-Ch/PGA NPs (200 nm, 0.2 PdI, 20 mV charge) were obtained, with high drug entrapment efficiency (>90 %), and fast release at physiological pH. Both free drug and Ibuf-Ch/PGA NPs significantly reduce PGE₂ in IL-1β-stimulated MSC pellets, but only Ibuf-NPs significantly stimulated collagen deposition, specifically collagen type 2. Overall, this study emphasizes a synergic potential of the NSAID Ibuprofen and Ch/PGA NPs to promote collagen deposition during chondrogenesis under pro-inflammatory conditions, opening new horizons in NSAID-based therapies to modulate inflammation in the context of OA.