Single cell embryo biopsy is a useful but invasive technique for preim
plantation diagnosis. Biopsy may be performed by physical (direct zona
puncture) or chemical methods (zona drilling with acid solution). Thi
s study has analysed the safety of a physical method of embryo biopsy
in the mouse. Six adult mice (male and female), three from biopsied em
bryos and three from a control group (non-biopsied) were subjected to
histopathological analyses. Macroscopically, the anatomy and morpholog
y of the internal organs in both groups were normal. Microscopic analy
ses of 15 major organs, which included the brain, heart, lung, liver,
kidney, stomach, intestine, voluntary muscle, spleen, pancreas, adrena
l, thymus, skin, testis (male) and ovary (female), in both groups were
all normal. These results showed that careful single cell embryo biop
sy by direct zona puncture performed at the 8-cell embryo stage had no
adverse influence on the macroscopic and microscopic structure of the
organs. The remaining pluripotential cells of biopsied embryos develo
ped normal microstructure according to the hereditary messages. Ideall
y, the safety of embryo biopsy requires observation of three stages af
ter embryo biopsy, namely embryonic and fetal development before birth
, neonatal assessment and long-term monitoring after birth.