Estrogen Receptor-Alpha and Estrogen Receptor-Beta Are Present in the Human Growth Plate in Childhood and Adolescence, in Identical Distribution

Abstract

Objective: To localize estrogen receptor-α (ER-α) and estrogen receptor-β (ER-β) within the growth plate and adjacent bony tissue of children in the prepubertal and pubertal age period. Methods: Tissue was taken during orthopedic surgery (epiphysiodesis) for correction of congenital or traumatic leg length difference in 2 prepubertal females and 2 adolescent males. Immunohistochemistry was performed on paraffin-embedded or cryostat sections by using commercially available rabbit polyclonal antibodies for ER-α and ER-β. Results: Both ER-α and ER-β were detected within the growth plate in all sections investigated. Immunostaining was restricted to hypertrophic chondrocytes. In the bony tissue adjacent to the growth plate, osteoblasts stained positive for both ER-α and ER-β, whereas osteocytes and osteoclasts were negative. Staining with ER-α was mainly nuclear but some cells also showed cytoplasmic signals, while ER-β staining was predominantly cytoplasmic, only few nuclei stained positive. There was no difference in the local distribution of both ERs between tissue from prepubertal and pubertal patients. Conclusion: Our findings indicate that the hypertrophic chondrocyte is the main target cell for estrogen action within the growth plate. The presence of ER in prepubertal children suggests that estrogens play a role in skeletal maturation under physiological conditions also in this age-group.