Effects of 17β-Estradiol combined with cyclical compressive stress on the proliferation and differentiation of mandibular condylar chondrocytes.

• E2 with CCS has different effects on MCCs proliferation and differentiation. • E2 at physiological concentration with CCS has synergistic effect. • E2 at non-physiological concentration with CCS has no synergistic effect. The aim of this study is to investigate the effects of 17β-Estradiol (E2) at different concentrations combined with cyclical compressive stress on the proliferation and differentiation of mandibular condylar chondrocytes (MCCs). MCCs, isolated from female Sprague-Dawley rats, were exposed to E2 at different concentration, cyclical compressive stress or the combination, effects of which on MCCs proliferation and differentiation were detected. E2 at physiological concentration (10−9 mol/L) has lower proliferative effects on MCCs, compared with non-physiological concentration (10-12 mol/L or 10-6 mol/L). For MCCs differentiation, effects of E2 at different concentration are totally opposite: E2 at 10−9 mol/L promotes MCCs differentiation, but at 10-12 mol/L or 10-6 mol/L, it inhibits MCCs differentiation. When combined with E2 at 10−9 mol/L, cyclical compressive stress shows synergistic effect on proliferation and differentiation. However, when combined with E2 at 10-12 mol/L or 10-6 mol/L cyclical compressive stress reverses the inhibition in MCCs differentiation provoked by E2 at 10-12 mol/L or 10-6 mol/L. Effects of E2 combined with cyclical compressive stress on MCCs proliferation and differentiation are different, which suggests that orthodontist should take fully consideration of the levels of E2 and adopt comprehensive strategies, so as to achieve better orthodontic effect. [ABSTRACT FROM AUTHOR]