Apoptotic cell death induced by local brain hyperthermia in a rat glioma model

• Published in: Acta neuropathologica 1998-10, Vol.96 (4), p.351-356
• Main Authors: UESUGI, S, YAMASHITA, K, NAKASHIMA, K, ITO, H
• Format: Article
• Language: English
• Subjects: Animals; Apoptosis; Apoptosis - physiology; Biological and medical sciences; Biotin; Brain - metabolism; Brain - pathology; Brain cancer; Brain Neoplasms - metabolism; Brain Neoplasms - pathology; Brain tumors; c-Jun protein; Cell death; Cell Death - physiology; Chromatin; DNA nucleotidylexotransferase; Fever; Fever - metabolism; Fever - pathology; Glioblastoma; Glioma; Glioma - metabolism; Glioma - pathology; Glioma cells; Hyperthermia; Immunoreactivity; In Situ Nick-End Labeling; Jun protein; Medical sciences; Necrosis; Neurology; Proto-Oncogene Proteins c-jun - metabolism; Rats; Staining and Labeling; Transcription factors; Tumor cells; Tumor Cells, Cultured; Tumors of the nervous system. Phacomatoses
• ISSN: 0001-6322; 1432-0533
• DOI: 10.1007/s004010050905

Hyperthermia has been shown to inhibit glioma growth both in vitro and in vivo, and has been reported to induce apoptosis of a variety of cells. We investigated the role of apoptosis in tumor cell death following hyperthermia in a rat glioma model representing human glioblastoma. Apoptotic cell death was evaluated by terminal deoxyribonucleotidyl transferase-mediated dUTP-biotin nick end-labeling (TUNEL) and hematoxylin and eosin (H & E) staining. We also examined c-Jun expression immunohistochemically. Apoptotic cell death in rat brain tumors that grew after implantation of C6 glioma cells showed regional differences. In all rats, apoptotic cells, characterized by extreme chromatin condensation and fragmented nuclei with apoptotic bodies in H & E-stained sections, were observed in the gliomas' necrotic cores. TUNEL-positive cells were observed in the border zones between necrotic and vital tumor cells. Before hyperthermia, TUNEL-positive cells were sporadically distributed in the vital tumor tissue. After hyperthermia, the number of TUNEL-positive cells in the peripheral region of the tumor mass increased significantly, reached a peak after 6 h and returned to the basal level within 24 h (P < 0.01). C-Jun protein immunoreactivity was not observed in the cells at the tumor periphery. These data indicate that significantly apoptotic cell death unrelated to c-Jun expression occurs after hyperthermia, and that this form of cell death may be the mechanism of tumor regression following hyperthermia treatment of intracranial gliomas.