Particle-induced X-ray emission (PIXE) for detection of lead in mouse blastocysts

Mice were injected intravenously with lead chloride, 75 micrograms/g body weight. The mice were in an experimental delay of implantation, which offered the functionally steady conditions required for developing the testing procedures. One day after the administration of lead, blastocysts were flushed from the uterine cavity, placed on thin foils of Kapton, and air-dried. The dried blastocysts were analyzed in a nuclear microprobe with a particle intensity of 10 nanoampere (nA) for 300 s using a spatial resolution of 3 microns. The average lead concentration of blastocysts at implantation was 3.90 micrograms/g dry weight. We judge this technique to be useful for evaluating the transport of heavy metals from mother to preembryos, not only under the present experimental conditions but also in normal pregnancies and in other species.