Prenatal Irradiation-Induced Hippocampal Abnormalities in Rats Evaluated Using Manganese-Enhanced MRI
Prenatal Irradiation-Induced Hippocampal Abnormalities in Rats Evaluated Using Manganese-Enhanced MRI
复制标题
DOI：
10.3389/fncir.2018.00112
复制
发表时间：
2018-12
影响因子：
3.5
通讯作者：
S. Saito;K. Sawada;I. Aoki
中科院分区：
文献类型：
--
作者：
S. Saito;K. Sawada;I. Aoki
本研究的目的是利用锰增强MRI （MEMRI）表征产前x射线照射后大鼠的海马异常。所有辐射暴露的大鼠脑均显示体积减小，侧脑室明显扩张。此外，海马内memri增强区域的体积比对照组减少了约25%，尽管海马的整体体积比对照组减少了约50%。MEMRI信号在齿状回门部和颗粒层以及CA3区的锥体层和锥体下区有较强的增强，在CA1/2锥体细胞层有中度增强。在辐射暴露的大鼠中，CA1/2区域的MEMRI信号由于其层流组织被破坏而消失，尽管DG和CA3区域的MEMRI信号持续强烈。辐射暴露大鼠组织病理学检查显示DG颗粒细胞层和CA3锥体细胞层解体，细胞密度降低。CA1/2锥体细胞层被入侵的异位细胞团破坏。神经细胞粘附分子（Neural cell adhesion molecule， NCAM）阳性纤维束在辐射暴露大鼠中持续存在，尽管它们在锥体上系CA3区分布异常，NCAM染色略有减少。此外，星形胶质细胞和小胶质细胞组成的胶质成分在DG而不是其他海马区域密集分布，其密度辐射暴露大鼠。综上所述，MEMRI信号增强可以描绘海马区域不同的神经元和/或胶质成分。我们在一个产前辐射暴露的大鼠模型中使用体内MEMRI表征了变形海马的微观结构及其宏观结构。本研究结果为检测神经发育障碍的非破坏性海马变形提供了有利的信息。
The aim of this study was to characterize hippocampal abnormalities in rats after prenatal x-ray irradiation using manganese-enhanced MRI (MEMRI). All radiation-exposed rat brains showed a reduced volume with prominent dilatation of lateral ventricles. Moreover, MEMRI-enhanced areas within the hippocampus were reduced in volumes by approximately 25% of controls, although the entire volume of hippocampus was decreased by approximately 50% of controls. MEMRI signals were enhanced strongly in the hilus and granular layer of the dentate gyrus (DG) and the pyramidal layer and infrapyramidal region of the CA3 region, and moderately along the CA1/2 pyramidal cell layer in the control rats. In radiation-exposed rats, MEMRI signals in the CA1/2 regions disappeared due to disrupting their laminar organization, although strong MEMRI signals were sustained in the DG and CA3 regions. Histopathological examinations in radiation-exposed rats revealed disorganizations of the DG granule cell layer and the CA3 pyramidal cell layer with reducing the cell density. The CA1/2 pyramidal cell layer was disrupted by invading ectopic cell mass. Neural cell adhesion molecule (NCAM)-positive fiber bundles were sustained in radiation-exposed rats, although they distributed aberrantly in the suprapyramidal CA3 region with a slight reduction of NCAM staining. Furthermore, glial components consisted largely by astrocytes and minor by microglia were densely distributed in the DG rather than in other hippocampal regions, and their density radiation-exposed rats. In conclusion, MEMRI signal enhancements could delineate different neuronal and/or glial components among hippocampal regions. We characterized microstructures of the deformed hippocampus as well as its macrostructures in a prenatally radiation-exposed rat model using in vivo MEMRI. The present findings provide advantageous information for detecting nondestructively hippocampal deformations in neurodevelopmental disorders.