Animal models of ovariectomy in rats demonstrate characteristics similar to early stage osteoarthritis

Abstract Purpose The aim of our study is to analyze the model of ovariectomy (OVX) in rats reproduced histological changes of osteoarthritis (OA). Methods For the development of the research, 12 Wistar rats were used, divided into 2 equal groups: Control Group - C (n = 6) and Osteoarthritis Group - OA (n = 6). After the 6-month experimental period, all rats were sacrificed and, subsequently, the entire knee joint complex was removed without disarticulation. For the histological evaluation of the tissue, the recommendations of the International Society for Research in OA (OARSI) were used. For data processing, each evaluation was statistically treated in both groups, comparing data from group C with the group OA. Results: Through the histological evaluation of OARSI, the evolution of OA in various tissues of the joint was evaluated. Although the OA group showed noticeable differences from group C, they were not as significant. Thus, only statistically significant favors were presented in the loss of the cartilaginous matrix (OA and C, p = 0.51), considering that the changes in the loss of ECM occurred only at the depth of 0% (superficial region), but at the depth of 50% (intermediate region) and 100% depth (deep region) did not exist. Conclusion Our study demonstrated that the OVX model is a good model to discuss OA, showing histological changes similar to those found in OA, the model demonstrated to have a progressive and slow characteristic since after the OARSI evaluations, prominent evidence was found in the initial manifestations of OA.