Efeitos dos hormônios tireoidianos na cinética de migração das células trofoblásticas e no perfil endócrino, angiogênico e imune da placenta de ratas e na expressão gênica das células trofoblásticas de camundongo

Abstract

The objective of this study was to evaluate in vivo the intrauterine trophoblast migration and the gene and protein expression of factors involved in the immune, endocrine and angiogenic profile of the placentas in hypothyroid and L-thyroxine-treated rats, as well as the differentiation and gene expression in vitro of hormonal, angiogenic and immune factors in mouse trophoblast cells with different doses of T3. The hypothyroidism was induced by daily administration of propylthiouracil. In the experiment in vivo, the animals were euthanized at 10, 14, 15, 16, 17, 18, and 19 days of gestation. We evaluated the endovascular and interstitial trophoblast migration and the immunohistochemical expression of INFy, MIF, iNOS, VEGF and Flk-1 in placental discs. The gene expression of TLR2, TLR4, INF, MIF, TNF, IL10, iNOS, PL-1, VEGF, Flk-1, PGF, rPlf, sFlt1, MMP2, MMP9 and placental leptin in the placenta was evaluated by real-time RT-PCR. For the experiment in vitro the animals were euthanized with 7.5 days of gestation to extraction and culture of the ectoplacental cone for 24 and 48 hours in standard medium without T3 (control) and with different doses of T3 (10-4 M, 10-7 M, 10-9 M). The gene expression of Tpbp, Prl3b1, VEGF, PGF, PL-1, and INF in the trophoblast cells was evaluated by real-time RT-PCR. Data from experiments in vivo and in vitro were analyzed by SNK test. Hypothyroidism reduced the endovascular and interstitial trophoblast migration and the gene and/or protein expression of TLR4, of pro- (INF) and anti-inflammatory (IL-10, iNOS) factors, of pro-angiogenic (VEGF, PGF) and hormonal (PL-1) factors and of the MMPs 2 and 9 and placental leptin (P<0.05). Hypothyroidism also increased the gene and/or protein expression of TLR2 and Flk-1 at 14 days of gestation, but decreased the gene expression of Flk-1 on day 10 (P<0.05). Regarding gene expression of rPlf, hypothyroidism increased at 10 and 19 days of gestation, but decreased on day 14, whereas excess of T4 increased at 19 days of gestation (P<0.05). Excess of T4 not only increased the gene and/or protein expression of the anti-inflammatory factors IL-10 and iNOS and pro-angiogenic (VEGF, PGF) and hormonal (PL-1) factors, as reduced on day 10 the expression of the pro-inflammatory factors TNF and MIF (P<0.05). However, at 19 days of gestation, the pro-inflammatory factors MIF and INF increased in T4-treated rats, unlike of the angiogenic factors VEGF, sFlt-1 and Flk-1, which decreased (P<0.05). Excess of T4 increased the gene expression of MMP-2 at 10 days of gestation, but reduced the endovascular trophoblast migration at 18 days of gestation (P<0.05). In vitro, the doses of 10-7 and 10-9 M of T3 increased the mRNA expression in the trophoblast cells for Tpbp, PGF, INF, and PL-1 with 24 and/or 48 hours of culture (P<0.05). The dose of 10-7 M of T3 also increased the gene expression for VEGF and Pl3b1 (P<0.05). The dose of 10-4 M of T3, on the contrary, reduced the gene expression for PL-1 and VEGF (P<0.05). We conclude that maternal thyroid dysfunction reduce the intrauterine trophoblast migration and differently affect the immune, endocrine and angiogenic profile in the placenta of rats, and these effects are dependent of the gestational period. Furthermore, triiodothyronine affects the gene expression in vitro of factors involved with the differentiation and hormonal, angiogenic and immune activity of mouse trophoblastic cells and these effects are dose-dependent.