Abstract
Purpose: Though the usefulness of carbon ion beam therapy has been reported recently, little has been known about effects of carbon ion beam on the normal brain tissue, especially at the developing stage. Hence, in this study, we investigated the effects of carbon ion beam on the early postnatal cerebellum using a modified organotypic slice culture system.
Methods: A cerebellum was dissected from 10-day-old Wistar rats. A vermis of the cerebellum was cut parasagittally into ∼600 μm-thick slices. The slices were treated with 12C ions (18.3 MeV/amu, 108 keV/µm, 0∼20 Gy) at JAEA, Takasaki. After irradiation, the slices were transferred into the incubation chamber and fixed at different times. Then, hematoxylin-eosin (HE) staining, in situ end labeling (TUNEL) methods, and immunostaining were performed.
Results: In the irradiated slices, the HE staining showed that the granule cells (GC) of the external granule layer (EGL) spread over the molecular layer and the zone of the EGL was extended. The GC in the irradiated slices at 5 days after irradiation still existed in the EGL, whereas almost all of the GC in the non-irradiated slices migrated toward internal granule layer. TUNEL methods showed that most of the GC in the EGL were densely stained at 24 h after irradiation. In addition, the processes of Bergmann glia retracted in the irradiated slices. These changes were similar to that occurred by x-irradiation.
Conclusions: The abnormality of EGL caused by carbon ion beam was as a result of the loss of migration ability of the GC.
