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(289) PORCINE ENDOMETRIAL EXPRESSION OF EXTRACELLULAR MATRIX COMPONENTS FOLLOWING ESTROGEN DISRUPTION OF PREGNANCY. Ashworth, Morgan1, Ross, Jason 1, Roberts, Jackie1, Malayer, Jerry2, Day, Anthony3, Geisert, Rodney1, 1 Oklahoma State University, Stillwater, OK2 Oklahoma State University, Stillwater, OK3 MRC Immunochemistry Unit, Oxford, UK ABSTRACT- In the pig, administration of estrogen to gilts on Days 9 and 10 of pregnancy causes conceptus fragmentation and death between Day 15 and 18 of gestation. Conceptus degeneration is associated with breakdown of the microvilli surface glycocalyx on the lumenal epithelium (LE). We previously identified endometrial expression of inter-alpha-trypsin inhibitor (ITI) and hyaluronic acid (HA), which are key components of extracellular matrix (ECM). Tumor necrosis factor stimulated gene-6 (TSG-6) serves as a linker for ECM expansion and is stimulated by prostaglandin E (PGE). We hypothesized that early estrogen administration alters the normal expression of ECM components forming LE glycocalyx. Bred gilts (4 gilts/trt/day) were treated with either 5 mg estradiol cypionate (EC) or corn oil (CO) on Day 9 and 10 of gestation. Following surgical removal of the uterine horns on either Day 10, 12, 13, 15 or 17 of gestation, conceptuses were flushed from the uterine horns and endometrium snap frozen in liquid nitrogen. Total RNA was extracted using TRIzol® and utilized for endometrial gene expression analysis of TSG-6, ITI, Has-2 and 3, and Cox-2 through quantitative RT-PCR. TSG-6 protein in uterine flushings was evaluated by western blot and PGE determined by immunoassay (R&D Systems). Endometrial TSG-6, ITI, Has-2 and -3 gene expression was detected throughout pregnancy, but was not altered by EC. EC increased endometrial Cox-2 gene expression 2-fold on Day 10 compared to CO (P< 0.06), but expression decreased 5-fold (P< 0.02) in EC compared to CO treated gilts on Day 12 of gestation. TSG-6 protein was detected across all days of gestation and was not affected by EC. Uterine content of PGE increased across the days of pregnancy (P<0.001). Present study demonstrates that EC treatment alters the pattern of endometrial Cox-2 gene expression which may play an important role in maintenance of LE glycocalyx during implantation in the pig. Estrogen endocrine disruption in the pattern of endometrial Cox-2 expression provides a potential mechanism by which total embryonic loss occurs in the pig. This work was supported in part by NRICGP/USDA grant 2002-35203-12262® KEY WORDS: uterus, endocrine disruption, Extracellular Matrix, pregnancy |
