Prostaglandins (PGs) are critical lipid mediators involved in many reproductive processes including luteolysis, maternal recognition of pregnancy, and implantation in domestic animals. In pigs, PGs, especially PGE2 and PGF2α, are produced in the uterine endometrium. The actions of PGE2 and PGF2α are mediated by signaling receptors, PTGERs and PTGFR, respectively, but their expression in the uterine endometrium is not well elucidated. In this study, we determined expression of PTGERs and PTGFR in the uterine endometrium during the estrous cycle and pregnancy in pigs. Uterine endometrial tissue samples were collected from Day (D) 12 and D15 of the estrous cycle and from D12, D15, D30, D60, D90, and D114 of pregnancy. Temporal expression of all genes studied was analyzed by real-time RT-PCR. PTGERs except for PTGER1 were expressed in the uterine endometrium during the estrous cycle and pregnancy. Levels of PTGER2 and PTGER3 mRNA increased during early pregnancy and late pregnancy, respectively, and levels of PTGER4 mRNA were not changed during pregnancy. Levels of PTGFR mRNA were highest on D90 of pregnancy. Results of this study showed that expression of PG receptors was dynamically regulated in the uterine endometrium during pregnancy in pigs. These results indicate that actions of PGs are dependent on types of receptors and is critical to support the establishment and maintenance of pregnancy at the maternal-fetal interface in pigs.

Successful pregnancy requires suppression of maternal immune response to the implanting conceptus, which acts as a semiallograft. During the implantation period in humans and rodents, various immune modulators are produced at the maternal-fetal interface and regulate functions of cytotoxic T cells and NK cells for protection of conceptuses from the maternal immune system. However, maternal immune responses to the conceptuses during the establishment and maintenance of pregnancy are not much understood in pigs which show true epitheliochorial type placentation. Previously, we reported that SLA-DQ molecule, a type of MHC class II molecules, is expressed in the uterine endometrium during pregnancy in a stage- and cell type specific manner, and that SLA-DQ expression is essential for the maintenance of pregnancy. Thus, to understand the role of SLA-DQ and maternal-fetal immune interaction, we examined expression of CD80 and CD86, co-stimulators for T cell activation, in the uterine endometrium during pregnancy. We also measured levels of CD80 and CD86 mRNAs in the uterine endometrium of pigs carrying conceptuses derived from somatic cell nuclear transfer (SCNT) and those from natural mating on Day 12 of pregnancy. Expression of endometrial CD80 mRNA was affected by day of pregnancy, and levels of CD80 mRNA were significantly higher on Day 15 of pregnancy than those of the estrous cycle. Expression of CD86 mRNA did not change during pregnancy. Levels of CD80 and CD86 mRNAs were not different in the uterine endometrium of pigs carrying SCNT derived conceptuses on D12 of pregnancy compared to those with conceptuses derived from natural mating. These findings suggest that CD80 and CD86 are involved in immune interactions at the maternal-fetal interface during pregnancy for the establishment and maintenance of pregnancy in pigs.

임신의 성립 및 유지에 중요한 자궁 내막과 호르몬의 변화는 생식기관에서 발현되는 K 통로의 발현을 변화시킬 수 있다. 본 연구는 한우의 임신 자궁 내막에서 K 통로의 발현 변화가 나타나는지 그리고 프로게스테론에 의해 그 발현량이 변화되는지를 확인하고자 수행하였다. 역전사중합효소 중합반응과 웨스턴블닷 분석을 통하여 임신한 한우의 자궁 내막에서 mRNA와 단백질의 발현 변화를 조사하였다. TREK-1을 제외한 K 통로의 mRNA 발현량이 임신 자궁 내막에서

Decorin (DCN) is a member of small leucine‐grich proteoglycans which are ubiquitous components of the extracellular matrix. It regulates many physiological processes, such as matrix formation, collagen fibrillogenesis, angiogenesis, cancer growth, and cardiovascular diseases. It has been shown that DCN is expressed in the uterus during pregnancy and modulates implantation and decidualization for the establishment and maintenance of pregnancy in mice and humans. Expression of DCN in the uterine endometrium during pregnancy has not been investigated in pigs. Thus, this study investigated expression of DCN in the uterine endometrium during the estrous cycle and pregnancy in pigs. Uterine endometrial tissues were from day (D) 12 and 15 of the estrous cycle and D12, D15, D30, D60, D90, and D114 of pregnancy. Northern blot and real‐gtime RT‐gPCR analyses showed that expression of DCN mRNA was detected throughout the estrous cycle and pregnancy with the highest levels during mid pregnancy. In situ hybridization analysis showed that DCN mRNA was localized to both luminal and glandular epithelia during the estrous cycle and pregnancy and also to chorionic membrane during mid pregnancy in pigs. To determine whether endometrial expression of DCN was affected by the somatic cell nuclear transfer (SCNT) procedure, DCN mRNA levels in the uterine endometrium from gilts with SCNT embryos on D30 of pregnancy were compared with those from gilts with normal embryos using real‐gtime RT‐gPCR analysis. The result showed that DCN mRNA levels in the uterine endometrium were not significantly different between gilts with normal embryos and SCNT embryos. These results suggest that DCN may play an important role for endometrial tissue remodeling during mid pregnancy, and DCN expression is not affected by the SCNT procedure at the early stage of pregnancy in pigs.

Salivary lipocalin (SAL1) is a member of the lipocalin protein family that has a property to associate with many lipophilic molecules and was identified as pheromone-binding protein in pigs. Our previous study has shown that SAL1 is expressed in the uterine endometrium in a cell type- and implantation stage-specific manner and secreted into the uterine lumen in pigs. However, function of SAL1 in the uterus during pregnancy in pigs is still not known. To understand physiological function of SAL1 in the uterine endometrium during pregnancy in pigs, it needs to elucidate the ligand(s) for SAL1. Thus, to identify the ligand for SAL1 in the porcine uterus, we collected uterine luminal fluid from pigs on day 12 of pregnancy by flushing with PBS. Proteins from the uterine luminal fluid were separated by ion exchange chromatography and gel filtration. Fractions containing SAL1 protein were pooled and concentrated. Immunoblot analysis confirmed successful purification of SAL1. Then, we extracted lipids from the purified SAL1 protein and analyzed the lipids by liquid chromatography-mass spectrometry, and predicted to be steroid hormones and prostaglandins as SAL1 ligands. Results in this study showed that SAL1 protein in the uterine secretions has a small lipophilic molecule as a natural ligand. Further characterization of ligand extracted from purified SAL1 will be useful for understanding physiological function of SAL1 during pregnancy and its application to increase the pregnancy rate in pigs.

본 연구는 한우의 자궁내막염에서 발현 변화를 보이는 유전자를 마이크로어레이를 이용하여 조사하였다. 정상적인 자궁내막과 자궁내막염이 있는 자궁내막을 비교한 결과, 전체 확인된 4,560개의 유전자 중 2,026개의 유전자가 자궁내막염에서 증가하였고, 2,534개의 유전자가 감소하였다. 본 연구에서는 상위 조절되는 유전자 10개씩을 정리하였다. 자궁내막염에서 filamin A, pancreatic anionic trypsinogen, Rho GDP dissociation inhibitor alpha, collagen type VI alpha 1, butyrate response factor 2, aggrecanses-2, annexin 14, aminopeptidease A, orphan transporter v7-3 및 epithelial stromal interaction 1의 발현율이 26배 이상 증가하였다. MHC class II antigen, integrin-binding sialoprotein, uterine milk protein precursor, down-regulated in colon cancer 1, glycoprotein 330, dickkopf-1, cfh protein, Ca2+-dependent secretion activator, UL16 binding protein 3 및 proenkephalin은 25.5배 이상 감소하였다. 본 연구에서 얻어진 유전자 정보는 한우의 자궁내막염 진단에 필요한 유용한 생물지표로 사용되어질 수 있을 것으로 사료된다.