Figure 1.

(A–D) Representative high-magnification histology of the rat offspring uterus at estrus. (A) Control (cornstarch-treated animals) group. Typical thickened uterine epithelium at estrus stage (*) with orderly and basally located nuclei. Original magnification, x400. (B) 0.2 mg/kg EE2 (positive control). Pseudostratified hyperplastic epithelium (*, columnar cells with less orderly and basally located nuclei) harboring cavities (arrows). Original magnification, x400. (C) 0.1 mg/kg per day BPA. Decreased luminal endometrial epithelium thickness with a foamy appearance (*) and cavities (arrows). Nuclei are less orderly and basally located. Original magnification, x400. (D) 50 mg/kg per day BPA. Significantly reduced thickness of the total epithelium (*). The luminal endometrial epithelium is riddled with cavities containing nuclei with condensed chromatin (arrows). Original magnification, x400. (E) Statistical analysis of height (µm) of the luminal epithelial cell layers from rat offspring after in utero treatment with BPA or EE2 at estrus stage. Values are based on analysis of three sections for each uterine specimen (six from each group). Quantification was performed on the digitized images of 10 systematic, randomly selected, representative fields and are reported as the mean ± SD. Co, control group, 31.0 ± 3.9 µm, n = 6; EE2, 0.2 mg/kg per day 17α-ethinyl estradiol group, 33.2 ± 9.4 µm, n = 6; BPA0.1, 0.1 mg/kg per day BPA, 27.8 ± 1.8 µm, n = 6; BPA50, 50 mg/kg per day BPA, 19.2 ± 6.0 µm, n = 6.