Influence of estradiol treatment on bone marrow cell differentiation in collagenase-induced arthritis.

OBJECTIVE AND DESIGN

Estrogen is one of the important regulators of the balance between bone formation and bone resorption that can modulate the levels and activity of certain growth factors and cytokines. In this study, we investigated the effect of 17β-estradiol (ED) on bone marrow (BM) cell differentiation in vivo and ex vivo in a mouse model of collagenase-induced osteoarthritis (CIOA).

SUBJECT

ICR (CD-2) female mice were used in present experiments (total number = 75) and bone marrow cells were used for in vitro studies.

TREATMENT

Mice were orally fed under different schemes with 17β-estradiol at a dose of 2 μg or 4 μg for 30 days.

METHODS

The effect of estradiol was estimated by histopathological, flow cytometry, and ELISA assays. Statistical differences were determined by one-way ANOVA.

RESULTS

Estradiol treatment ameliorated cartilage destruction and osteophyte formation if started from day 0 of CIOA induction, attended with a decrease of uterine and ovarian weights. Long time treatment lowered the percentage of megakaryocyte/platelet (CD62P+) populations and osteoclast (RANK+) populations in BM. Cells obtained from estradiol-treated CIOA mice showed inhibited capacity to differentiate into RANK+ and mesenchymal cells under osteoclastogenic conditions in vitro. Estrogen decreased serum IL-6 levels.

CONCLUSION

Results indicate a potential protective role for estrogen against the development of OA.