Effect of Estradiol on Chondrocytes in the Active Stage of Collagenase- Induced Osteoarthritis

Aim: The aim of the present study is to examine the effect of estradiol on chondrocyte inflammatory potential and apoptosis in a mouse model of osteoarthritis (OA). Background: OA is a degenerative joint disease related to articular cartilage disintegration, together with substantial changes in the subchondral bone. Estradiol (ED) is considered to be an important player in maintaining bone homeostasis. Increasing evidence support the association between the severity of cartilage erosion and chondrocyte death. Objective: It is of great importance to elucidate the role of chondrocytes in the development of OA in relation to estrogen levels. Methods: The present work was conducted on a model of collagenase-induced osteoarthritis (CIOA) in ICR (CD-2) mice. The cytokine and MMP-3 concentrations were assayed by ELISA, and apoptosis of chondrocytes was determined by flow cytometry. Results: ED decreased the number of cultured TGF-β1 positive chondrocytes, reduced the percentage of double-positive CD220+/TNF-α+ chondrocytes. ED reduced the rate of apoptosis and MMP- 13 production of stimulated arthritic chondrocytes, and inhibited the release of inflammatory IL-6 and IL-8 cytokines in vitro. Conclusion: Our results show that ED affects chondrocyte functions as a part of its anti-arthritic mechanism of action and it might be a perspective drug for healing OA.