Abstract
<Purpose> It has not been elucidated whether heavy-ion beam irradiation modulates the biology of glioblastoma at the cellular level. Our project is designed to investigate whether heavy-ion beam exposure is effective on glioblastoma cells. We examined a human glioblastoma cell line (CGNH89) by morphological and immunohistochemical techniques after X-ray or heavy-ion beam exposure.
<Method> For X-ray and heavy-ion beam, CGNH89 cells were divided into 3 groups; control, 5Gy and 10Gy exposure. For each group, cells were fixed at the same time-points. Hematoxylin-Eosin (HE) and immunohistochemical staining were done in formalin-fixed cells. For electron microscopy, cells were fixed in fixative (1% glutaraldehyde, 10% formaldehyde). These samples were postfixed with osmium and embedded in Quetol 812. Ultrathin sections were examined under a tansmission electron microscope.
<Results and Discussion> After the exposure, both living cells and mitotic cells decreased in cell number. In the HE staining, nuclear condensation and apoptotic bodies increased after exposure. MIB-1 labeling index decreased in the early stage after exposure, but increased in later stages. It is suggested that cell cycle arrest and induction of apoptosis was induced by X-ray and heavy-ion beam exposure in CGNH89 cells.
Ultrastructurally, the nuclei and cytoplasm after exposure showed a tendency to increase in size. Cellular swelling seemes to depend on the swelling of mitochondria, increase of cellular organelles, cytoskeleton, and secondary lysosome. However we did not find out either apoptotic body or necrotic change. We conclude that X-ray and heavy-ion beam exposure might trigger the same morphological changes in the surviving CGNH-89 cells.
