Objective To determine the effects of different estrogen concentrations on the proliferation and differentiation of human embryo mandibular condylar chondrocytes (MCCs).Methods In vitro-cultured MCCs were incubated and treated with estrogen at different concentrations. The MCCs were identified by toluidine blue and type Ⅱ collagen immunocytoche-mical methods, and cell proliferation was monitored using methyl thiazolyl tetrazolium assay.Results The addition of 10-12 or 10-6 mol·L-1 exogenous estrogen inhibited the growth of MCCs, whereas addition of 10-10 or 10-8 mol·L-1 exogenous estrogen promoted growth. These estrogen effects were time-dependent.Conclusion Estrogen can affect cellular MCCs proliferation and differentiation in a biphasic manner depending on the concentration. Estrogen may be vital in the maintenance of normal functions of the temporomandibular joint (TMJ) and may be involved in the progression of certain TMJ diseases.
