Arthritis is a common disease in aged people, and is clinically divided into rheumatoid arthritis (RA) and osteoarthritis (OA). Although common symptoms such as pain are present, the underlying pathological mechanisms are slightly different. Therefore, the objectives of the present study were to compare joint damage induced by RA and OA by analyzing the major morphological and molecular differences, and to propose a suitable therapeutic intervention based on the pathophysiological conditions of bones and joints. For the RA animal model, 8-week-old DBA1/J mice were immunized with bovine type II collagen emulsified in complete Freund’s adjuvant (CFA). Normal C57BL/6 mice (over 2 years of age) were used for OA. The clinical arthritis score was calculated using a subjective scoring system, and paw thicknesses were measured using calipers. The serum TNFα level was analyzed using an ELISA kit. Micro- CT was used to identify pathological characteristics and morphological changes. In collagen-induced RA mice, there were increased ankle joint volumes and clinical scores (p<0.01). The concentration of TNFα was significantly increased from 3 to 7 weeks after immunization. Micro-CT images showed trabecular bone destruction, pannus formation, and subchondral region destruction in RA mice. OA among aged mice showed narrowed joint spaces and breakdown of articular cartilage. This study suggests that a careful therapeutic intervention between RA and OA is required, and it should be based on morphological alteration of bone and joint.

ABSTRACT   INTRODUCTION   MATERIALS AND METHODS    Animals    Induction of RA and Measurements    Tissue Collection    Analysis of Serum TNFα Concentration    Micro-Computed Tomography    Statistical Analysis   RESULTS    Characterization of Collagen-Induced RA Animals   DISCUSSION   REFERENCES

• Yunkyung Hong(Department Rehabilitation Science in Interdisciplinary PhD Program, Inje University, These authors contributed equally.)
• Palaksha Kanive Javaregowda(Cardiovascular & Metabolic Disease Center, College of Biomedical Science & Engineering, These authors contributed equally.)
• Sang-Kil Lee(Cardiovascular & Metabolic Disease Center, College of Biomedical Science & Engineering)
• Sang-Rae Lee(National Primate Research Center, Korea Research Institute of Biotechnology)
• Kyu-Tae Chang(National Primate Research Center, Korea Research Institute of Biotechnology) Corresponding author
• Yonggeun Hong(Department Rehabilitation Science in Interdisciplinary PhD Program, Inje University, Cardiovascular & Metabolic Disease Center, College of Biomedical Science & Engineering, National Primate Research Center, Korea Research Institute of Biotechnology) Corresponding author