OBJECTIVETo study the expression of the estrogen receptor (ER) and type II collagen in the mandibular condylar cartilage of the human embryo.

METHODSThe expression and localization of ERalpha, ERbeta, and type II collagen in the mandibular condylar cartilage of the human embryo were examined through hematoxylin-eosin (HE) and immunohistochemistry staining.

RESULTSType II collagen was primarily localized in the transitional and hypertrophic layers of the condylar cartilage. ERa was mostly expressed in the transitional and hypertrophic cartilaginous layers of the condylar cartilage. ERa was evenly distributed in the cell, whereas ERbeta was localized in the nuclei. No expression of type II collagen and ER was found in the fibrage and the proliferative layer although minimal expression was found in the calcified cartilage.

CONCLUSIONThe distribution of ER and type II collagen in the mandibular condylar cartilage was consistent. Estrogen can selectively combine with different subtypes of ER that regulate the ability of the condylar cartilage cells to secrete type II collagens.