Magee-Womens Research Institute, Department of Obstetrics, Gynecology and Reproductive Sciences, University of Pittsburgh, Pittsburgh, PA, USA.
Department of Radiation Oncology, University of Pittsburgh, Pittsburgh, PA, USA.
Placenta. 2014 Feb;35(2):85-91. doi: 10.1016/j.placenta.2013.12.011. Epub 2014 Jan 2.
Exposure to low-dose radiation is widespread and attributable to natural sources. However, occupational, medical, accidental, and terrorist-related exposures remain a significant threat. Information on radiation injury to the feto-placental unit is scant and largely observational. We hypothesized that radiation causes trophoblast injury, and alters the expression of injury-related transcripts in vitro or in vivo, thus affecting fetal growth.
Primary human trophoblasts (PHTs), BeWo or NCCIT cells were irradiated in vitro, and cell number and viability were determined. Pregnant C57Bl/6HNsd mice were externally irradiated on E13.5, and placentas examined on E17.5. RNA expression was analyzed using microarrays and RT-qPCR. The experiments were repeated in the presence of the gramicidin S (GS)-derived nitroxide JP4-039, used to mitigate radiation-induced cell injury.
We found that survival of in vitro-irradiated PHT cell was better than that of irradiated BeWo trophoblast cell line or the radiosensitive NCCIT mixed germ cell tumor line. Radiation altered the expression of several trophoblast genes, with a most dramatic effect on CDKN1A (p21, CIP1). Mice exposed to radiation at E13.5 exhibited a 25% reduction in mean weight by E17.5, and a 9% reduction in placental weight, which was associated with relatively small changes in placental gene expression. JP4-039 had a minimal effect on feto-placental growth or on gene expression in irradiated PHT cells or mouse placenta.
While radiation affects placental trophoblasts, the established placenta is fairly resistant to radiation, and changes in this tissue may not fully account for fetal growth restriction induced by ionizing radiation.
低剂量辐射的暴露很常见，其源自天然来源。然而，职业性、医疗性、意外性和与恐怖主义相关的辐射暴露仍然是一个重大威胁。关于辐射对胎-胎盘单位造成损伤的信息很少，且主要是观察性的。我们假设辐射会导致滋养层细胞损伤，并改变体外或体内与损伤相关的转录本的表达，从而影响胎儿生长。
体外培养原代人滋养层细胞（PHT）、BeWo 或 NCCIT 细胞，检测细胞数量和活力。在 E13.5 时对怀孕的 C57Bl/6HNsd 小鼠进行外部照射，在 E17.5 时检查胎盘。使用微阵列和 RT-qPCR 分析 RNA 表达。在添加用革兰氏阳性菌杀菌素 S（GS）衍生的硝酮 JP4-039 的情况下重复进行实验，该物质用于减轻辐射诱导的细胞损伤。
我们发现，体外照射的 PHT 细胞的存活率优于照射的 BeWo 滋养层细胞系或辐射敏感的 NCCIT 混合生殖细胞瘤系。辐射改变了几种滋养层基因的表达，对 CDKN1A（p21，CIP1）的影响最为显著。在 E13.5 时暴露于辐射的小鼠在 E17.5 时体重平均减少 25%，胎盘重量减少 9%，这与胎盘基因表达的相对较小变化相关。JP4-039 对辐照 PHT 细胞或小鼠胎盘的胎-胎盘生长或基因表达的影响很小。
虽然辐射会影响胎盘滋养层细胞，但已建立的胎盘对辐射具有较强的抵抗力，并且这种组织的变化可能不能完全解释电离辐射引起的胎儿生长受限。
