Diffusion tensor imaging of brain abnormalities induced by prenatal exposure to radiation in rodents

• Published in: PloS one Vol. 9; no. 9; p. e107368
• Main Authors: Saito, Shigeyoshi, Sawada, Kazuhiko, Hirose, Miwa, Mori, Yuki, Yoshioka, Yoshichika, Murase, Kenya
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 09.09.2014; Public Library of Science (PLoS)
• Subjects: Abnormalities; Alzheimer's disease; Alzheimers disease; Animal experimentation; Animals; Anisotropy; Biology; Brain; Brain abnormalities; Brain Diseases - pathology; Brain research; Calbindin-D28K; Cell density; Cerebral Cortex - pathology; Cerebral Cortex - radiation effects; Communications technology; Cortex; Diagnostic imaging; Diffusion; Diffusion rate; Diffusion Tensor Imaging - methods; Drug dosages; Embryos; Experiments; Exposure; Female; Health physics; Health sciences; Hippocampus; Hippocampus - pathology; Hippocampus - radiation effects; Immunology; Ionizing radiation; Laboratory animals; Magnetic resonance; Magnetic resonance imaging; Magnetic Resonance Imaging - methods; Male; Medical imaging; Medical research; Medical technology; Medicine; Medicine and Health Sciences; Myelin; Myelin Sheath - pathology; Myelin Sheath - radiation effects; Neonates; Nervous System Malformations - pathology; Neuroimaging; NMR; Nuclear magnetic resonance; Physics; Pregnancy; Pregnant women; Prenatal experience; Prenatal exposure; Prenatal Exposure Delayed Effects - pathology; Pyramidal cells; Pyramidal Cells - pathology; Pyramidal Cells - radiation effects; Radiation; Radiation Dosage; Rats; Reduction; Rodents; Staining; Ventricle; Ventricles (cerebral); X radiation; X-rays; X-Rays - adverse effects; Japan
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0107368

We assessed brain abnormalities in rats exposed prenatally to radiation (X-rays) using magnetic resonance imaging (MRI) and histological experiments. Pregnant rats were divided into 4 groups: the control group (n = 3) and 3 groups that were exposed to different radiation doses (0.5, 1.0, or 1.5 Gy; n = 3 each). Brain abnormalities were assessed in 32 neonatal male rats (8 per group). Ex vivo T2-weighted imaging and diffusion tensor imaging (DTI) were performed using 11.7-T MRI. The expression of markers of myelin production (Kluver-Barrera staining, KB), nonpyramidal cells (calbindin-D28k staining, CaBP), and pyramidal cells (staining of the nonphosphorylated heavy-chain neurofilament SMI-32) were histologically evaluated. Decreased brain volume, increased ventricle volume, and thinner cortices were observed by MRI in irradiated rats. However, no abnormalities in the cortical 6-layered structure were observed via KB staining in radiation-exposed rats. The DTI color-coded map revealed a dose-dependent reduction in the anisotropic signal (vertical direction), which did not represent reduced numbers of pyramidal cells; rather, it indicated a signal reduction relative to the vertical direction because of low nerve cell density in the entire cortex. We conclude that DTI and histological experiments are useful tools for assessing cortical and hippocampal abnormalities after prenatal exposure to radiation in rats.