Vargas-Villavicencio J A, Cedillo-Peláez C, Rico-Torres C P, Besné-Mérida A, García-Vázquez F, Saldaña J I, Correa D
Laboratorio de Inmunología Experimental, Instituto Nacional de Pediatría, SSa. Torre de Investigación, Av. Insurgentes Sur 3700-C, Col. Insurgentes Cuicuilco, Mexico City 04530, Mexico.
Laboratorio de Inmunología Experimental, Instituto Nacional de Pediatría, SSa. Torre de Investigación, Av. Insurgentes Sur 3700-C, Col. Insurgentes Cuicuilco, Mexico City 04530, Mexico; Doctorado en Ciencias de la Salud y Reproducción Animal, FMVZ, Universidad Nacional Autónoma de Mexico, Mexico City, Mexico.
Exp Parasitol. 2016 Jul;166:116-23. doi: 10.1016/j.exppara.2016.04.002. Epub 2016 Apr 9.
Congenital transmission of Toxoplasma gondii may occur if the mother gets infected for the first time while pregnant. The risk of mother-to-child transmission depends on the gestation trimester at infection, being lowest in the first and highest in the last. Conversely, fetal damage is frequent and more severe at the beginning of pregnancy. The objective of this study was to evaluate congenital transmission and pathological aspects in the placenta and the fetus using a mouse model of congenital infection of the second gestation third. Forty-five female BALB/c mice were infected intravenously with 2.5-10.0 × 10(6) tachyzoites of the ME49 strain at middle gestation. Samples of maternal spleen and fetal/placental units were taken 72 h later. We determined parasite load and vertical transmission by qPCR, as well as damage macroscopically and by histopathology. With the lowest dose, 18% of the fetuses were infected. Also, 40% of fetuses/litter were altered, while this value was 10% in the control group (P < 0.05). These results are similar to those described in humans in terms of vertical transmission and fetal damage during the second third of gestation. The maternal spleen had 10-1000 times more tachyzoites than the placenta, and the later retained 90-99% of the parasites that could reach the fetus. Nevertheless, we found resorptions, abortions or fetal tissue damage in the presence but also in the absence of parasites. Our data indicate a strong protective effect of maternal organs and the placenta against fetal infection, but extensive damage of the later may led to resorption or abortion without vertical transmission.
如果母亲在怀孕期间首次感染弓形虫，就可能发生先天性传播。母婴传播的风险取决于感染时的妊娠 trimester，在妊娠早期最低，在妊娠晚期最高。相反，胎儿损伤在妊娠开始时很常见且更严重。本研究的目的是使用妊娠中期先天性感染的小鼠模型评估胎盘和胎儿的先天性传播及病理情况。45只雌性BALB/c小鼠在妊娠中期经静脉注射2.5 - 10.0×10⁶个ME49株速殖子。72小时后采集母鼠脾脏和胎儿/胎盘单位样本。我们通过qPCR测定寄生虫载量和垂直传播情况，以及通过宏观和组织病理学评估损伤情况。使用最低剂量时，18%的胎儿被感染。此外，40%的胎儿/窝出现异常，而对照组这一比例为10%（P < 0.05）。这些结果在妊娠中期的垂直传播和胎儿损伤方面与人类描述的结果相似。母鼠脾脏中的速殖子比胎盘多10 - 1000倍，胎盘保留了90 - 99%可能到达胎儿的寄生虫。然而，我们发现无论有无寄生虫存在，都有吸收、流产或胎儿组织损伤的情况。我们的数据表明母体器官和胎盘对胎儿感染有很强的保护作用，但胎盘的广泛损伤可能导致吸收或流产而无垂直传播。 （注：原文中“gestation trimester”疑有误，可能是“gestation trimester period”之类表述，这里暂按原文翻译）
