Subchondral Bone Plate Changes More Rapidly than Trabecular Bone in Osteoarthritis

Area of Science:

• Orthopedics and Rheumatology
• Biomedical Engineering
• Comparative Pathology

Background:

• Osteoarthritis (OA) is a prevalent joint disorder marked by cartilage loss and subchondral bone alterations.
• Understanding the early temporal and spatial relationship between bone remodeling and OA onset is crucial for developing effective interventions.

Purpose of the Study:

• To investigate the relationship between subchondral bone plate (Sbp) and trabecular bone (Tb) remodeling and early osteoarthritis (OA) in Dunkin Hartley (DH) guinea pigs compared to a control strain (BS2).
• To determine the temporal and spatial characteristics of bone changes preceding clinical signs of OA.

Main Methods:

• Utilized micro-computed tomography (micro-CT) to quantify growth plate thickness (GpTh), Sbp thickness (SbpTh), Tb thickness (TbTh), and bone mineral density (BMD) in Sbp and Tb.
• Analyzed tibias from DH and BS2 guinea pigs at 10, 16, 24, and 30 weeks of age, calculating rates of change between intervals.
• Focused on medial and lateral compartments to assess spatial differences in bone remodeling.

Main Results:

• Significantly greater rates of change in SbpTh and TbTh were observed in DH guinea pigs compared to BS2 controls during the 10-16 week interval.
• Bone mineral density changes in Sbp and Tb were also significantly higher in DH guinea pigs early on, particularly in the medial compartment.
• These bone remodeling changes preceded previously reported microscopic and cellular indicators of OA in the DH strain.

Conclusions:

• Rapid early remodeling and density changes in subchondral and trabecular bone of DH guinea pigs suggest a strong link to early OA pathology.
• The pronounced changes in the medial compartment further support the role of subchondral bone alterations in disease initiation.
• These findings highlight the potential of early bone changes as biomarkers for OA development.