Abstract: Objective To investigate the expression and distribution of LPA-R3 during the period of mouse embryo implantation. Methods Seventyeight mice were randomly divided into pregnancy group（EM>n/EM>=36）,pseudopregnancy group(EM>n/EM>=36) and control group(EM>n/EM>=6).Immunohistochemistry and reverse transcription polymerase chain reation (RT-PCR) and Western blotting were employed to analyze the expression and distribution of LPA-R3 in the uterine endometrium during mouse embryo implantation. Results LPA-R3 was mainly expressed in cytoplasm of glandular and luminal epithelium and part of stromal cells of mouse uterus.The LPA-R3 mRNA and protein level in the uteri increased during early pregnancy, increased at 3 days post coitus (3 d.p.c.), peaking around 4 d.p.c., periimplantation period, then returned to the basal levels on 5 d.p.c. This temporal profile of LPA-R3 expression in the uterus of pseudopregnant mice was essentially similar to that observed in normal pregnant mice. The expression level of LPA-R3 receptor protein and mRNA had no significant difference between pseudopregnant mice and normal pregnant mice(EM>P/EM>>0.05).Conclusion LPA-R3 may participate in the period

Key words: Lysophosphatidic acid receptor 3, Embryoimplantation, Endometrial receptivit, Immunohistochemistry, RT-PCR, Western blotting, Mouse