Cortical fiber distribution in the somatosensory cortex of rats following prenatal exposure to X-irradiation.
Exposure of fetal rats to X-irradiation at a dose of 1.5 Gy on gestational day 15 results in severe microcephaly. In these X-irradiated rats with microcephaly, a possible alteration of local circuits in the somatosensory cortex was examined using a fluorescent dye, DiI. The dye was placed at the superficial part of the transversely sectioned somatosensory cortex just beneath the pial surface of both the control and X-irradiated rats on postnatal day 11. In the controls, DiI-labeled fibers showed a layer-dependent distribution in the somatosensory cortex, whereas in the X-irradiated rats, this layer-dependent distribution of DiI-labeled fibers was distorted. Furthermore, the fasciculus observed beneath cortical layer VI (white matter), which was made of DiI-labeled axons originating from the cortical neurons, was well developed in the controls. On the other hand, in the X-irradiated rats, the fasciculus made of DiI-labeled fibers was split, reduced in number, and irregularly distributed. These observation suggest that prenatal exposure of fetal rats to X-irradiation may affect the development of local circuits in the cerebral cortex, and may also damage the axonal projection of cortical neurons to the thalamus.
Funahashi
A
A
Behavior and Information Processing, Department of Social and Human Science Informatics, Nagoya University, Nagoya, Japan.
Darmanto
W
W
Inouye
M
M
D000016:Abnormalities, Radiation-Induced / Q000209:etiology / Q000473:pathology; D000818:Animals; D002540:Cerebral Cortex / Q000473:pathology / Q000528:radiation effects; D005260:Female; D008297:Male; D018811:Maternal Exposure; D008744:Methylamines; D008746:Methylazoxymethanol Acetate / Q000009:adverse effects / Q000031:analogs & derivatives* / Q000494:pharmacology; D008831:Microcephaly / Q000209:etiology* / Q000473:pathology; D009412:Nerve Fibers / Q000473:pathology / Q000528:radiation effects*; D009474:Neurons / Q000473:pathology / Q000528:radiation effects*; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D051381:Rats; D017208:Rats, Wistar; D013003:Somatosensory Cortex / Q000473:pathology / Q000528:radiation effects*; D013723:Teratogens / Q000494:pharmacology
C422026:1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarboxyamine perchlorate; D008744:Methylamines; D013723:Teratogens; D008746:Methylazoxymethanol Acetate; C030667:methylazoxymethanol