Study for mechanism of retained placenta in cattle

本研究旨在探讨胎膜潴留（RFM）的发生与牛胎盘组织中孕酮、雌二醇-17β、前列腺素E2 （PGE2）、前列腺素F2α (PGF2α)、催产素（OT）、催产素受体（OT- r）、内皮素-1和血管紧张素II （Ang II）激素浓度的关系。立即（0 h）和分娩后6 h采集胎盘组织。采用酶免疫法测定了RFM、非RFM和对照奶牛母体和胎儿胎盘组织中的激素浓度。RFM组、非RFM组和对照组P4和E2浓度无差异。RFM组胎盘母区PGF2α平均浓度低于非RFM组和对照组。在母体组织中，RFM组的OT和OT- r浓度低于分娩后0和6 h的非RFM组。此外，在胎盘组织的母胎部分，RPM组的Ang II浓度均高于其他组。综上所述，ET-1和Aug - II可能在胎盘单位中发挥不同的组织特异性作用，可能会放大局部内分泌级联反应，包括OT、OT- r和PGF2α的相互作用，这是奶牛正常胎盘分离所必需的。第二项研究的目的是确定奶牛妊娠期胎盘中类固醇生成酶和蛋白水解酶mRNA表达与分娩后胎膜释放过程之间的关系。根据分娩后胎膜释放时间将标本分为：1)早期组，分娩后6 h内胎膜释放；2)晚期组，分娩后6 ~ 12 h释放胎膜。另外，对来自屠宰场的胎盘虫作为妊娠期样本进行了检查，根据冠臀长度确定其胎龄为第1（0-3个月）、第2（4-6个月）和第3（7-9个月）。子叶中甾体生成酶的mRNA表达量明显高于甲骨组织，P450scc和star在胎盘组织中的mRNA表达模式趋于平行。另一方面，尽管timp-2 mRNA在腕骨和子叶组织中的表达水平相似，但妊娠期和产后腕骨组织中mmp-2和mmp-9 mRNA的表达水平约为子叶组织的10倍。此外，骨关节组织中mmp-2和mmp-9以及子叶组织中mmp-9和timp-2的表达模式在产前和产后有显著变化。我们的研究结果表明，甾体原酶mRNA表达与mmps/timp-2之间的关系可能在维持妊娠和分娩后胎膜脱离中起关键作用。少

The aim of the first study was to evaluate the relationship between the occurrence of retention of the fetal membranes (RFM) and the hormonal concentrations of progesterone, estradiol-17β, prostaglandin E2 (PGE2), prostaglandin F2α (PGF2α), oxytocin (OT), oxytocin receptor (OT-R), endothelin-1 and angiotensin II (Ang II) in the placental tissues of cattle. The placental tissues were collected immediately (0 h) and at 6 h after parturition. The hormonal concentrations were measured by enzyme immunoassay in maternal and fetal placental tissues from RFM, non-RFM and control cows. There were no differences in P4 and E2 concentrations among the RFM, non-RFM and control groups. The mean PGF2α concentration of the RFM group was lower than those of the non-RFM and control groups in the maternal part of the placenta. In maternal tissues, the OT and OT-R concentrations in the RFM group were lower than those at 0 and 6 h after parturition in the non-RFM group. Additionally, the Ang II concentrati … More on of the RPM group in both the maternal and fetal parts of placental tissues tended to be higher than those of the other groups. In conclusion, the present results suggest that ET-1 and Aug II may play differential tissue-specific roles in the placental unit that may amplify the local endocrinological cascade involving OT, OT-R and PGF2α interactions which are necessary for normal placental separation in the cow.The aim of the second study was to determine the relationship between mRNA expressions of steroidogenic and proteolytic enzymes in placentomes during gestation and the process of releasing fetal membranes after parturition in cattle. Based on the releasing time of fetal membranes after parturition, the specimens were classified as : 1)the early group, whereby the fetal membranes were released within 6 h after parturition ; and 2)the late group, whereby the fetal membranes were released 6 to 12 h after parturition. Placentomes from a slaughterhouse were additionally examined as samples for the gestation period, whose fetal age was determined as the 1st (0-3 months), 2nd (4-6 months) and 3rd (7-9 months) trimesters by crown rump length. Rather higher mRNA expressions of steroidogenic enzymes in cotyledon than caruncle tissues were observed, and the mRNA expression patterns of P450scc and star tended to be parallel in both placental tissues. On the other hand, although the expression levels of timp-2 mRNA in both caruncle and cotyledon tissues were similar, expression levels of mmp-2 and mmp-9 mRNA were approximately 10 times higher in caruncle than cotyledon tissue during gestation and postpartum. Moreover, marked changes in myna expression patterns between pre- and postpartum periods were observed in mmp-2 and mmp-9 in caruncle tissues and mmp-9 and timp-2 in cotyledon tissues. Our results suggest that the relationship between mRNA expressions of steriodogenic enzymes and mmps/timp-2 may have a critical role in the maintenance of pregnancy and fetal membrane detachment after parturition. Less