Pathologic Changes in Subchondral Bone Microarchitecture Differ Between ACLT, NIKI, and MMT Models of Post-Traumatic...

Area of Science:

• Biomedical Engineering
• Orthopedics
• Skeletal Biology

Background:

• Osteoarthritis (OA) involves subchondral bone remodeling driven by abnormal joint loading.
• Pre-clinical OA models may exhibit unique loading patterns, influencing bone microstructure.
• Comparing different models is crucial for understanding OA pathophysiology and trauma mechanisms.

Purpose of the Study:

• To compare subchondral bone microstructural changes across different rat models of late-stage OA.
• To elucidate the relationship between joint trauma mechanisms and bone remodeling in OA.
• To identify distinct bone phenotypes associated with specific OA induction methods.

Main Methods:

• Osteoarthritis (OA) induced in male Lewis rats via medial meniscus transection (MMT), anterior cruciate ligament transection (ACLT), and non-invasive knee injury (NIKI).
• Microcomputed tomography (micro-CT) used to quantify trabecular and cortical bone microstructure at study endpoint.
• Key bone parameters analyzed include bone volume, thickness, number, and separation.

Main Results:

• Non-invasive knee injury (NIKI) model showed decreased cortical (Ct.Th) and trabecular thickness (Tb.Th).
• Medial meniscus transection (MMT) and anterior cruciate ligament transection (ACLT) models exhibited subchondral bone sclerosis with increased Ct.Th and Tb.Th.
• NIKI animals displayed bone loss indicators: decreased bone volume (BV/TV), trabecular number (Tb.N), and increased trabecular separation (Tb.Sp).

Conclusions:

• End-stage subchondral bone changes significantly differ across MMT, NIKI, and ACLT rat OA models.
• The specific mechanism of joint injury is a critical factor influencing OA pathophysiology at later disease stages.
• These findings highlight the importance of model selection for studying OA and evaluating therapeutic interventions.