Fig. 4.
Apoptotic effects of 24-h exposure to E2 at the blastocyst stage. (A) TUNEL-positive cell shown as arrow in the ICM cells of blastocysts. TUNEL-positive cell shown as blank arrow in the trophectoderm of blastocysts. (B) Apoptosis of blastocyst cells occurred at E2 levels above a threshold of 10−4 M. ∗P < 0.05 versus the control group. The sample size shown in each group (control:32; 10−7 M:30; 10−6 M:32; 10−5 M:31; 10−4 M:30 respectively). The apoptotic cells were noted using the TUNEL assays. Data were recruited from three experiments and analyzed by one-way analysis of variance (ANOVA).