Mechanical loading mitigates osteoarthritis symptoms by regulating the inflammatory microenvironment in a mouse model

Area of Science:

• Biomedical Engineering
• Immunology
• Orthopedics

Background:

• Osteoarthritis (OA) involves cartilage degeneration and inflammation driven by chondrocyte apoptosis.
• Synovial inflammation and macrophage polarization are key features of OA pathogenesis.
• The protective mechanisms of mechanical loading in OA are not fully understood.

Purpose of the Study:

• To investigate the effects of mechanical loading on synovial macrophage polarization in an OA mouse model.
• To elucidate the molecular pathways mediating the anti-inflammatory effects of mechanical loading in OA.

Main Methods:

• Histology, cytology, and molecular analyses were performed on mouse OA models.
• Synovial tissue was examined for macrophage polarization (M1/M2) and inflammation markers.
• PI3K/AKT/NF-κB signaling pathway activity was assessed.

Main Results:

• Osteoarthritis induced synovial lining enlargement, increased M1 macrophages, and elevated pro-inflammatory cytokines.
• Mechanical loading reduced cartilage degradation and synovial inflammation.
• Mechanical loading decreased M1 macrophages, increased M2 macrophages, and suppressed PI3K/AKT/NF-κB signaling.

Conclusions:

• Mechanical loading ameliorates OA symptoms by modulating synovial macrophage polarization.
• The PI3K/AKT/NF-κB pathway is a critical target for mechanical loading's protective effects in OA.
• This study provides insights into mechanical loading as a therapeutic strategy for osteoarthritis.