2017 ISAKOS Biennial Congress IFOSMA ePoster #5026

 

Subchondral Bone Changes in Early Osteoarthritis

Hang Fang, MD, PhD, Guangzhou, Guangdong CHINA
Ian Welch

The Third Affiliated Hospital of Southern Medical University, guangzhou , guangdong, china

FDA Status Not Applicable

Summary

Subchondral Bone Changes in Early Osteoarthritis

Abstract

Objective

To examine early subchondral bone changes in the DMM (destabilization of medial meniscus) mouse model of post-traumatic osteoarthritis (PTOA). Methods: C57/B6 mice were subjected to DMM or sham surgery at 12-weeks of age and harvested at 2-, 5- and 10-week post-surgery. Catwalk gait analyses, Micro-Computed Tomography (μCT), Toluidine Blue, Picrosirius Red and Tartrate-Resistant Acid Phosphatase (TRAP) staining were used to investigate gait patterns, 3D joint morphology, bone mineral density (BMD) of subchondral bone, histology of cartilage and bone, collagen organization and activity of osteoclasts, respectively. Results: OA progressed from mild to moderate or severe to severe over the 10-week time-course. Gait disparity occurred only at 10-week post-surgery. Histology showed osteophyte formation at the medial side of the joint as early as 2 weeks following DMM, developing from cartilage-like to bone-like tissue through endochondral ossification over the time course. Subchondral BMD was decreased at 2 weeks in some animals, then increased at 5 and 10 weeks post-surgery in DMM mice, indicating bone loss followed by subchondral bone sclerosis during OA development. TRAP staining showed increased osteoclast activity at the site of osteophyte formation of DMM joints at 5- and 10-week time points. Conclusions: Subchondral bone turnover with decreased BMD occurred as early as 2 weeks after DMM surgery, followed by bone sclerosis and increased BMD at later time-points. Gait disparity only occurred at later stage of OA in DMM mice.