The effect of estrogen on type 2 collagen levels in the joint cartilage of post-menopausal murine subjects

Cartilage degradation frequently occurs during the postmenopausal period due to a decrease in type 2 collagen and constitutes a condition affected by the level of estrogen in the body. The purpose of this study is to prove that such postmenopausal reductions in estrogen levels influence the type 2 collagen expression in cartilage. Oophorectomies were performed on 54 Rattus norvegicus subjects and each of which was subsequently assigned to one of six different groups. 17β-estradiol present in the blood of the subjects was examined by means of ELISA technique, while the expression of MMP-13 and type 2 collagen in their knee joint cartilage was assessed immunohistochemically. A significant post-oopho-rectomy decrease of 17β-estradiol was detected in subjects (p<0.05), while the expression of MMP-13 increased appreciably (p<0.05) and a marked decrease in type 2 collagen expression occurred (p<0.05). The reduction in 17β-estradiol promoted an increase in the expression of MMP-13 and a decrease in type 2 collagen expression.