Evaluation of articular changes using a rat mono-iodoacetate-induced shoulder arthritis model by histology and radiology.

The rat mono-iodoacetate arthritis model has been used in studies on the hip, knee, and ankle joints. Few studies have explored its utility in shoulder arthritis research, and none have evaluated the effects of time and different mono-iodoacetate doses on arthritis progression. Therefore, we developed a rat mono-iodoacetate shoulder arthritis model to evaluate articular changes through radiological and histological analyses. Sprague-Dawley rats (n=108) were equally divided into groups that were intra-articularly injected with 0.5 mg of mono-iodoacetate (in 50 µL of purified water), 2.0 mg of mono-iodoacetate (in 50 µL of purified water), or purified water (50 µL; sham group). Throughout the study period, 18 rats (six per group) were evaluated by computed tomography and assessed using the Larsen's classification system; 90 rats were further evaluated histologically using the Osteoarthritis Research Society International scoring system. Computed tomography revealed that the groups injected with mono-iodoacetate developed arthritis and osteophytes 14 days after injection, which progressed temporally. The Larsen's grades worsened over time; at all time points, the scores were higher in the group injected with 2.0 mg of mono-iodoacetate than in the group injected with 0.5 mg of mono-iodoacetate. Furthermore, concurrent with the worsening Larsen's grades, the Osteoarthritis Research Society International scores also significantly increased over time; at all time points, they were higher in the group injected with 2.0 mg of mono-iodoacetate than in the group injected with 0.5 mg of mono-iodoacetate. Our rat mono-iodoacetate shoulder arthritis model revealed radiologically and histologically confirmed temporal and mono-iodoacetate dose-dependent arthritic changes. This article is protected by copyright. All rights reserved.