Microfluidic chip-based co-culture system for modeling human joint inflammation in osteoarthritis research

Area of Science:

• Biomedical Engineering
• Cell Biology
• Rheumatology

Background:

• Osteoarthritis (OA) involves complex interactions between multiple cell types in the joint.
• Current in vitro models often fail to capture this multi-tissue complexity, limiting their translational value.
• Understanding these interactions is crucial for developing effective OA therapies.

Purpose of the Study:

• To develop and validate a novel microfluidic co-culture system for recapitulating human joint microenvironments.
• To establish both healthy and inflammatory (OA-like) joint models using this system.
• To assess the viability, cytotoxicity, and metabolic activity of cells within the microfluidic models.

Main Methods:

• Co-culture of human osteoblasts, chondrocytes, fibroblasts, and macrophages (M0 and M1 phenotypes) in a microfluidic device.
• Induction of M1 macrophage phenotype using interferon-gamma (IFN-γ) and lipopolysaccharide to model inflammation.
• Assessment of cell viability (NucBlue™/NucGreen™), cytotoxicity (LDH assay), and metabolic activity (PrestoBlue™ assay).

Main Results:

• The microfluidic system maintained high initial cell viability (>83%) for both healthy and diseased models at 24 hours.
• No significant cytotoxicity was observed in the co-culture models, indicating preserved cell membrane integrity.
• Cellular metabolic activity was significantly higher (5.3-5.9 times) in the microfluidic co-cultures compared to standard monolayer cultures.

Conclusions:

• The developed microfluidic co-culture system effectively recapitulates the multi-tissue complexity of human joints.
• This model serves as a promising platform for studying the pathophysiology of rheumatic diseases like osteoarthritis.
• The system holds potential for pre-clinical testing of novel therapeutic agents for joint diseases.