Expression of bone morphogenetic proteins 4 and 7 and their receptors IA, IB, and II in human ovaries from fetuses and adults

Objective: To investigate the immunocytochemical and mRNA expression of bone morphogenetic proteins 4 (BMP-4) and 7 (BMP-7) and their three receptors (BMPR-IA, BMPR-IB, and BMPR-II) in ovaries from human adults and fetuses. Design: Immunocytochemical and in situ hybridization study. Setting: Major tertiary care and referral academic centers. Patient(s): Sixteen adolescents/adults aged 13-38 years and 31 women undergoing second and third trimester pregnancy terminations. Intervention(s): None. Main Outcome Measure(s): Immunocytochemistry and in situ hybridization on paraffin sections of human ovaries from fetuses and adults. Result(s): The expression of the proteins for BMP-4 and BMP-7 and their receptors was detected in oogonia/oocytes and stroma cells from both sources (fetuses and women/adolescents). BMP-7 and the three receptors were identified in all of these granulosa cells, and BMP-4 was detected only in the granulosa cells of women/adolescents. Transcripts for all five ligands were identified in stroma cells of all samples and in fetal oogonia/oocytes. BMPR-IA and BMPR-IB mRNA expression was also identified in oocytes from women/adolescents. BMP-7 and BMPR-IA mRNA staining was detected in fetal granulosa cells. Conclusion(s): This is the first report of the expression of BMP-4 and BMP-7 and their receptors in human ovaries from fetuses as well as adults. However, to elucidate whether indeed BMP-4 or BMP-7 are involved in the initiation of human primordial follicular growth, they should be added to the culture medium.