Novaro V, Rettori V, González E T, Jawerbaum A, Faletti A, Canteros G, de Gimeno M A
Centro de Estudios Farmacológicos y Botánicos (CEFYBO). Buenos Aires, Argentina.
Prostaglandins. 1996 Jun;51(6):363-76. doi: 10.1016/0090-6980(96)00043-3.
Embryonic implantation is a complex process in which both maternal and embryonic signals are involved. In the present study, we evaluated changes in uterine prostaglandins production and nitric oxide synthase (NOS) activity during the course of early pregnancy and their interaction during implantation in rats. Uterine phospholipase A2 (PLA2) activity is increased on days 5 (day of ovoimplantation) and 6, compared to preimplantation days (3 and 4). This enhanced activity might be responsible for the observed increase in uterine PGE and PGF2 alpha production observed on day 5 of pregnancy, which induces endometrial vascular permeability and decidualization. When embryo access to the uterus is impaired, the increase of PG production is suppressed. During postimplantation, PGE levels return to preimplantation values, while PGF2 alpha decreased with respect to preimplantation values. Uterine NOS activity is also increased on day 4 and reaches a maximum on day 5, with a profile similar to PGE and PGF2 alpha. Dexamethasone administered in vivo decreased uterine NOS activity on day 4 of pregnancy but not on day 5, suggesting the presence of at least two types of NOS enzymes in the early days of pregnancy. A competitive inhibitor of NOS, L-NAME (600 and 1000 microM) induced a decrease in PGE and PGF2 alpha production in uterine tissue on day 5 of pregnancy. These results suggest the existence of a physiologically relevant nitridergic system which modulates prostaglandin production in the rat uterus during embryonic implantation.
胚胎着床是一个涉及母体和胚胎信号的复杂过程。在本研究中，我们评估了大鼠妊娠早期子宫前列腺素生成和一氧化氮合酶（NOS）活性的变化，以及着床过程中它们之间的相互作用。与着床前的第3天和第4天相比，子宫磷脂酶A2（PLA2）活性在第5天（卵子着床日）和第6天增加。这种增强的活性可能是导致妊娠第5天观察到的子宫PGE和PGF2α生成增加的原因，这会诱导子宫内膜血管通透性和蜕膜化。当胚胎进入子宫受阻时，PG生成的增加受到抑制。在着床后，PGE水平恢复到着床前的值，而PGF2α相对于着床前的值下降。子宫NOS活性在第4天也增加，并在第5天达到最大值，其变化趋势与PGE和PGF2α相似。体内给予地塞米松可降低妊娠第4天的子宫NOS活性，但对第5天没有影响，这表明在妊娠早期至少存在两种类型的NOS酶。NOS的竞争性抑制剂L-NAME（600和1000 microM）可导致妊娠第5天子宫组织中PGE和PGF2α生成减少。这些结果表明，在胚胎着床期间，大鼠子宫中存在一个生理上相关的氮能系统，该系统调节前列腺素的生成。
