Second Hospital of Shanxi Medical University

Critical-sized bone defects still present significant clinical challenges because traditional bone graft methods have noticeable limitations.

This research developed and assessed a new bone tissue engineering method that combined collagen hydrogel with Icariin-loaded chitosan nanoparticles (ICACNPs) and adipose-derived stem cells (ASCs). Collagen hydrogels incorporated with Icariin-loaded chitosan nanoparticles (ICACNPs) were fabricated using ionotropic gelation.

The composite hydrogels maintained ASC viability while showing improved swelling properties and increased antioxidant activity. The COLICACNPASC group, which combined ICACNPs and ASCs demonstrated significantly enhanced new bone formation and reduced inflammation while showing elevated levels of osteogenic and angiogenic markers (osteopontin, osteonectin, VEGF, bFGF, and TGF-β) when compared to other test groups. The combination treatment resulted in marked downregulation of pro-inflammatory markers IL-6 and TNF-α as well as the oxidative stress marker GPx.

The combined use of ICACNPs and ASCs creates a powerful system for bone regeneration which results in improved osteogenic and angiogenic outcomes as well as better immunomodulation in the calvarial bone defect model.

Osteoarthritis (OA) is a degenerative joint disease characterized by an increasing prevalence and complex pathogenesis. Despite significant research efforts, understanding its mechanisms and developing effective treatments remain challenging. The development of in vitro models that accurately mimic the native articular microenvironment while preserving chondrocyte phenotype is crucial for advancing OA research. In this study, we constructed an Alginate-Hyaluronic Acid-Type I Collagen (Alg-HA-Col) composite hydrogel through physical mixing and chemical cross-linking. This composite matrix exhibited exceptional stability over 28 days under simulated physiological conditions. Neonatal murine chondrocytes encapsulated within Alg-HA-Col hydrogels for 28 days maintained their phenotype better than those cultured in monolayer, as evidenced by higher expression levels of SOX9, type II collagen, and aggrecan. Furthermore, by adjusting the component ratios, the stiffness of Alg-HA-Col hydrogels could mimic the stiffness of the pericellular matrix (PCM) in both physiological and pathological states, referred to as Firm and Soft. Chondrocytes cultured in Alg-HA-Col hydrogels with varying stiffness showed decreased expression of marker proteins, increased cellular mortality, and elevated inflammatory factor expression as stiffness decreased. Therefore, Alg-HA-Col hydrogels with tunable stiffness effectively simulated the physiological and pathological states of cartilage, providing an ideal three-dimensional (3D) matrix for chondrocyte culture. Additionally, this model's long-term culture stability offers potential applications in osteoarthritis drug therapy and cartilage tissue engineering.