Treatment with 25 μg/mL etoposide for 5 h causes the activation of histone H2AX (γH2AX) at the sites of DNA damage.

<p>Representative fluorescent images of oocytes and embryos that were unexposed (control) or exposed to etoposide (25 μg/mL) for 5 h. Cells were immunostained with an antibody against γH2AX. Hoechst was used to stain DNA.