Effect of diethylstilbestrol on cell proliferation and expression of epidermal growth factor in the developing female rat reproductive tract

Abstract

To evaluate mechanisms of cell proliferation in the fetal female rat reproductive tract, diethylstilbestrol (DES) effects on cell division and estrogen receptor (ER), epidermal growth factor (EGF) and EGF receptor (EGF-R) expressions were determined from gestational day (GD) 15·5 to 21·5. Reproductive tracts were evaluated within three regions along the Müllerian duct axis; these were proximal, middle and caudal, which differentiate into oviduct, uterus and upper vagina respectively. In fetuses from non-treated dams, epithelial and mesenchymal proliferation, as evaluated by 5-bromo-2 -deoxyuridine incorporation, was decreased with development in all regions of the Müllerian duct. EGF levels were determined by immunohistochemistry. Müllerian epithelial EGF immunoreactivity was intense in the proximal and middle regions on GDs 15·5 and 17·5. EGF staining remained intense only in the proximal epithelia by GD 19·5 and was weak in the caudal epithelium, but substantially reduced throughout epithelia in all regions by GD 21·5. Thus, decreased cell proliferation correlated with decreased EGF expression in the developing Müllerian duct. DES (100 µg/kg body weight) was injected from GD 15 to 19 and female fetuses were collected on GD 19·5. DES increased Müllerian duct cell proliferation in the proximal epithelium and mesenchyme but decreased it in the caudal epithelium compared with oil-treated controls. No proliferative DES effect was observed in any cell type in the middle region. Müllerian duct EGF immunoreactivity was suppressed by DES compared with oil. Competitive RT-PCR indicated DES also decreased mRNAs for EGF, ER 1 and ER 2, but not ER and EGF-R. These results indicate EGF may be an important regulatory factor of Müllerian duct cell proliferation, and that DES may alter cell proliferation by disrupting normal EGF, ER 1 and ER 2 expression in the developing female rat reproductive tract.

Changes in ontogenetic expression of estrogen receptor alpha and not of estrogen receptor beta in the female rat reproductive tract

“…Indeed, autoradiography revealed extensive binding by [ 3 H]DES in mouse reproductive tract on GD 17 following transplacental exposure (Holderegger & Keefer 1986). In our previous report, we suggested that DES may act mainly via ER , since DES down regulated ER 1 and ER 2 mRNAs, but not ER mRNA (Okada et al 2001). Based on the present findings, however, transplacental exposure to estrogen agonists including DES may act in the Müllerian duct via dominantly expressed ER .…”

Exposure to Diethylstilbestrol during Pregnancy Modulates MicroRNA Expression Profile in Mothers and Fetuses Reflecting Oncogenic and Immunological Changes

“…DES exposure of prenatal mice has been shown to cause various abnormalities, including those in the thymus, skeletal tissues, female reproductive organs, and muscles (Takasugi, 1963;Maier et al, 1985;Okada et al, 2001). In the thymus, prenatal exposure to DES has been shown to cause thymic atrophy and several other changes, such as apoptosis, T cell differentiation, immunotoxicity, and immunosuppression (Ford et al, 1983;Brown et al, 2006a).…”

Role of foxj1 and estrogen receptor alpha in ciliated epithelial cell differentiation of the neonatal oviduct

“…In developing mice and rats, ER is expressed in oviductal epithelial and stromal cells, but ER is absent in both cell types (Yamashita et al 1989, Li 1994, Mowa & Iwanaga 2000, Okada et al 2002a, 2003. Pre-and neo-natal exposure to diethylstilbestrol (DES), a synthetic estrogen, caused abnormal morphology and altered cell proliferation in mouse and rat oviducts (Newbold et al 1983, Okada et al 2001. However, the oviduct of mice lacking ER was resistant to neonatal DES exposure (Couse et al 2001) indicating an essential role of ER in mediating the estrogen effect on developing neonatal oviduct.…”