Objective    To investigate the effect of PTEN gene in the mouse uterus during embryo implantation.    Methods    Real-time fluorescence quantitative PCR (FQ-PCR) was used to detect PTEN mRNA expressed in the endometria of the nonpregnant mice and the late pregnant mice (day 1

day 3

day 4

day 5 and day 7)

with 20 mice sacrificed at each fixed day. Out of another 20 3-day pregnant mice

ten received PTEN antisense oligonucleotide at the horn of uterus and ten received normal saline to count the blastocysts at pregnant day 8.    Results    The PTEN mRNA/β-actin mRNA in pregnant mice was higher than that of nonpregnant mice

gradually hoisted as days passed by

and reached the highest at pregnant day 5. The number of blastocysts in the mice that received PTEN antisense oligonucleotide was fewer than that received normal saline.     Conclusion    PTEN persistently expresses in mouse endometria during the early pregnancy and maybe participate in the regulation process of mouse blastodyst implantation.