Expression of transforming growth factor (TGF)-β1, TGF-β2, and TGF-β3 and of type I and II TGF-β receptors during the development of the human fetal ovary

Abstract

Objective: To investigate the role of transforming growth factor-β (TGF-β) in the regulation of human fetal ovarian development. Design: Reverse transcription-polymerase chain reaction and comparative immunohistochemical analysis of the localization and staining intensity of TGF-β1, TGF-β2, and TGF-β3, and of their receptors. Setting: Academic research environment. Patient(s): Human fetal ovaries were obtained from terminated normal intact pregnancies at 11–24 weeks’ gestation. Intervention(s): None. Main Outcome Measure(s): Messenger RNA analysis and protein expression of TGF-β isoforms and their receptors in human fetal ovaries at 11–24 weeks of gestational age. Result(s): Messenger RNAs for the three TGF-β isoforms and the two TGF-β receptors were demonstrated in all the developmental ages studied: 11, 14, 18, 20, and 22 weeks of gestation. During the first trimester, immunohistochemical analysis for TGF-β1, TGF-β2, and TGF-β receptor type I revealed homogeneous light staining of the ovary. Staining for TGF-β3 and TGF-β receptor type II was predominantly in the oocytes. During the second trimester, staining for all three TGF-β isoforms and both receptors was predominantly in the oocytes. In addition, for receptor types I and II, staining was observed in the pregranulosa cells. Conclusion(s): Our findings support the hypothesis that expression of the TGF-β system changes from the first to the second trimester of fetal development and may have an autocrine and/or paracrine regulatory role during ovarian development.