Expression And Regulation Of PPARδ Gene In Rat And Mouse Uterus During Early Pregnancy

Peroxisome proliferator-activated recePtors (PPARs) are a family of nuclear hormonereceptors. PPAR suPerfamily consists of three members: a, 5 and y. The aim of thisstudy was to examine PPAR5 expression in rat and mouse uterus during earlypregnancy, pseudopregnancy, delayed implanation, artificial decidualization andregulation by steroid hormone treatment by in sitU hybridization andinununohistochemisny The expression of PPAR gene in preimplanation embryowas also determined by RT-PCR.In ra uterus, expression of PPAR6 mRNA was gradually decreased in the luminalepithelium and increased in the glandular epithelium from day l to 5 of pregnancy.Both PPAR5 mRNA and protein were strongly expressed in the decidua from day 6to 9 of pregnancy. There was a low level of PPAR5 mRNA expression in the luminalepithelium and the glandular epithelium from day l to 8 of pseudopregnancy.PPAR5 protein was not detected in the luminal epithelium and the glandulaxepithelium from day l to 8 of pseudopregnancy. PPAR8 expression in thesub-luminal stroma surrounding implanting blastocyst was intensively induced whendelayed implantation was terminated by estrogen treatment, while there was a weaksignal in the luminal and glandular epithelium under delayed imPlantation. PPAR5was expressed in the decidua under artificial decidualization, While PPAR8 was notdetected in the luminal epithelium of control uterus horn. PPAR6 expression in theuterus of ovariectomized mice was significantly stimulated by estrogen or acombination of estrogen and progesterone.In mouse uterus, epession of PPAR6 mANA was not detected in the luminal and4T7W_<sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub>$g_<sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub><sub>2002 ^ 5 ^glandular epithelium from day 1 to 4 of pregnancy. Both PPAR8 mRNA and proteinwere strongly expressed in the decidua from day 5 to 8 of pregnancy. There was no detectable signal of PPAR6 mRNA and protein expression in the luminal and glandular epithelium from day 1 to 8 of pseudopregnancy. PPAR8 expression in the sub-luminal stroma surrounding implanting blastocyst was intensively induced when delayed implantation was terminated by estrogen treatment, while there was no detectable signal in the uterine luminal and glandular epithelium under delayed implantation. PPAR8 was expressed in the decidua under artificial decidualization, while was not detected in the luminal epithelium of control uterus horn. PPAR5 expression in the uterus of ovariectomized mice was significantly stimulated by estrogen or a combination of estrogen and progesterone. PPAR8 mRNA was detected in oocytes and preimplantation embryos at the stages of zygote, 2-cell, 4-cell, 8-cell, morula and blastocyst.In conclusion, these results suggest that PPAR8 expression is closely related to embryo implantation and decidualization.