The expression of vascular endothelial growth factor (VEGF) and fibroblast growth factor (FGF)2 in the irradiated brain was examined to test how a single high dose radiation, similar to that used for intraoperative radiation therapy given to the normal cerebrum, can affect the vascular endothelium. After a burr hole trephination in the rat skull, the cerebral hemisphere was exposed to a single 10 Gy dose of gamma rays, and the radiation effect was assessed at 1, 2, 4, 6, and 8 weeks after irradiation. His-tological changes, such as reactive gliosis, inflammation, vascular proliferation and necrosis, were correlated with the duration after irradiation. Significant VEGF and FGF2 expression in the 2- and 8-week were detected by enzyme-linked immunosorbent assay quantification in the radiation group. Immunohistochemical study for VEGF was done and the number of positive cells gradually increased over time, compared with the sham operation group. In conclusion, the radiation injuries consisted of radiation necrosis associated with the expression of VEGF and FGF2. These findings indicate that VEGF and FGF2 may play a role in the radiation injuries after intraoperative single high-dose irradiation.
Animals ; Brain/metabolism/pathology/radiation effects ; Brain Injuries/etiology/*metabolism/*pathology ; Fibroblast Growth Factor 2/*metabolism ; Necrosis ; Radiation Injuries/*pathology ; Radiosurgery/*adverse effects ; Rats ; Rats, Sprague-Dawley ; Up-Regulation/radiation effects ; Vascular Endothelial Growth Factor A/*metabolism

The extracellular matrix metalloproteinase inducer (EMMPRIN) has been known to play a key regulatory role in pathological angiogenesis. A elevated activation of vascular endothelial growth factor (VEGF) following radiation injury has been shown to mediate blood-brain barrier (BBB) breakdown. However, the roles of EMMPRIN and VEGF in radiation-induced brain injury after gamma knife surgery (GKS) are not clearly understood. In this study, we investigated EMMPRIN changes in a rat model of radiation injury following GKS and examined potential associations between EMMPRIN and VEGF expression. Adult male rats were subjected to cerebral radiation injury by GKS under anesthesia. We found that EMMPRIN and VEGF expression were markedly upregulated in the target area at 8-12 weeks after GKS compared with the control group by western blot, immunohistochemistry, and RT-PCR analysis. Immunofluorescent double staining demonstrated that EMMPRIN signals colocalized with caspase-3 and VEGF-positive cells. Our data also demonstrated that increased EMMPRIN expression was correlated with increased VEGF levels in a temporal manner. This is the first study to show that EMMPRIN and VEGF may play a role in radiation injuries of the central nervous system after GKS.
Animals ; Antigens, CD147/*metabolism ; Brain/blood supply/metabolism/pathology/*radiation effects ; Brain Injuries/metabolism/pathology ; Caspase 3/metabolism ; Gamma Rays/*adverse effects ; Immunohistochemistry ; Male ; Microscopy, Electron, Transmission ; Parietal Lobe/metabolism/pathology/radiation effects ; Radiation Injuries, Experimental/metabolism ; Radiosurgery/adverse effects ; Rats ; Rats, Wistar ; Time Factors ; Vascular Endothelial Growth Factor A/*metabolism

Tumor cell proliferation, infiltration, migration, and neovascularization are known causes of treatment resistance in glioblastoma multiforme (GBM). The purpose of this study was to determine the effect of radiation on the growth characteristics of primary human GBM developed in a nude rat. Primary GBM cells grown from explanted GBM tissues were implanted orthotopically in nude rats. Tumor growth was confirmed by magnetic resonance imaging on day 77 (baseline) after implantation. The rats underwent irradiation to a dose of 50 Gy delivered subcuratively on day 84 postimplantation (n = 8), or underwent no radiation (n = 8). Brain tissues were obtained on day 112 (nonirradiated) or day 133 (irradiated). Immunohistochemistry was performed to determine tumor cell proliferation (Ki-67) and to assess the expression of infiltration marker (matrix metalloproteinase-2, MMP-2) and cell migration marker (CD44). Tumor neovascularization was assessed by microvessel density using von-Willebrand factor (vWF) staining. Magnetic resonance imaging showed well-developed, infiltrative tumors in 11 weeks postimplantation. The proportion of Ki-67-positive cells in tumors undergoing radiation was (71 +/- 15)% compared with (25 +/- 12)% in the nonirradiated group (P = 0.02). The number of MMP-2-positive areas and proportion of CD44-positive cells were also high in tumors receiving radiation, indicating great invasion and infiltration. Microvessel density analysis did not show a significant difference between nonirradiated and irradiated tumors. Taken together, we found that subcurative radiation significantly increased proliferation, invasion, and migration of primary GBM. Our study provides insights into possible mechanisms of treatment resistance following radiation therapy for GBM.
Animals ; Brain Neoplasms ; metabolism ; pathology ; radiotherapy ; Cell Line, Tumor ; Cell Movement ; radiation effects ; Cell Proliferation ; radiation effects ; Female ; Glioblastoma ; metabolism ; pathology ; radiotherapy ; Humans ; Hyaluronan Receptors ; metabolism ; Immunohistochemistry ; Ki-67 Antigen ; metabolism ; Magnetic Resonance Imaging ; Matrix Metalloproteinase 2 ; metabolism ; Microvessels ; pathology ; Neoplasm Transplantation ; Neovascularization, Pathologic ; pathology ; Radiation Tolerance ; Radiotherapy, High-Energy ; Rats ; Rats, Nude

Monitoring the long-term radiotherapy-associated molecular changes in low-grade gliomas (LGGs) facilitates the understanding of LGG response to radiotherapy. In this study, we used immunohistochemistry to analyze the expression of Ki-67, tumor protein P53 (TP53), P21, and P27 in 8 paired WHO grade II astrocytoma samples. The interval between radiotherapy (RT) and the second surgery was more than 3 months in all cases. The average Ki-67 labeling index (LI) was 5.3% in pre-RT samples and 11.54% in post-RT samples. Ki-67 LI was higher in the primary tumors that underwent malignant transformation observed at the second surgery after radiation. Post-RT Ki-67 LI decreased in 2 cases with an interval of less than 12 months between RT and the second surgery. TP53 expression was found in 3 out of 4 pre-RT samples with malignant transformation and in 1 out of 4 pre-RT samples without malignant transformation. Post-RT TP53 increased in 2 cases in which increased expression of P21 or P27 was also observed. Our study suggests that radiotherapy can inhibit WHO grade II astrocytoma proliferation as reflected by Ki-67 LI, but the effect attenuates with time. In addition, there is a tendency of malignant transformation for WHO grade II astrocytomas with a high Ki-67 level or TP53 expression in initial samples.
Adult ; Astrocytoma ; metabolism ; pathology ; radiotherapy ; surgery ; Brain Neoplasms ; metabolism ; pathology ; radiotherapy ; surgery ; Cell Proliferation ; radiation effects ; Cell Transformation, Neoplastic ; radiation effects ; Cyclin-Dependent Kinase Inhibitor p21 ; metabolism ; Cyclin-Dependent Kinase Inhibitor p27 ; metabolism ; Female ; Humans ; Immunohistochemistry ; Ki-67 Antigen ; metabolism ; Male ; Middle Aged ; Neoplasm Grading ; Tumor Suppressor Protein p53 ; metabolism

OBJECTIVETo study the clinicopathologic features of delayed radiation-induced brain injury after radiotherapy for brain tumor.

METHODSThe clinical, histopathologic and immunohistochemical features of 9 cases with delayed radiation-induced injury were evaluated.

RESULTSThe disease occurred from 6 months to 12 years after radiotherapy and often presented with headache and muscle weakness. Magnetic resonance imaging showed peripheral enhancing lesions with slight mass effect and surrounding edema. Microscopically, the major changes included coagulative necrosis, fibrinoid necrosis of vessels, vascular hyalinization with luminal stenosis and peripheral reactive gliosis. Immunostaining for hypoxia-inducible factors 1α was positive in reactive astrocytes.

CONCLUSIONSDelayed radiation-induced brain injury is a relatively common complication of radiation therapy. The lesion was frequently misdiagnosed as brain tumor. Correct diagnosis relies on clinical, radiologic and pathologic correlation.

Aged ; Brain Neoplasms ; radiotherapy ; Female ; Glioma ; radiotherapy ; Humans ; Hypoxia-Inducible Factor 1, alpha Subunit ; metabolism ; Magnetic Resonance Imaging ; Male ; Middle Aged ; Radiation Injuries ; diagnosis ; diagnostic imaging ; metabolism ; pathology ; surgery ; Radiotherapy ; adverse effects ; Tomography, X-Ray Computed

Apoptosis is a programmed, physiologic mode of cell death that plays an important role in tissue homeostasis. As for the central nervous system, ischemic insults can induce pathophysiologic cascade of apoptosis in neurophils. Impairment of astroctye functions during brain ischemia can critically influence neuron survival by neuronglia interactions. We aimed to elucidate the protective effect of ketamine on apoptosis by energy deprivation in astrocytes. Ischemic insults was induced with iodoacetate/ carbonylcyanide mchlorophenylhydrazone (IAA/CCCP) 1.5 mM/ 20 micrometer or 150 micrometer/2 micrometer for 1 hr in the HTB-15 and CRL-1690 astrocytoma cells. Then these cells were reperfused with normal media or ketamine (0.1 mM) containing media for 1 hr or 24 hr. FITC-annexin-V staining and propidium iodide binding were determined by using flow cytometry. Cell size and granularity were measured by forward and side light scattering properties of flow cytometry system, respectively. An addition of keta-mine during reperfusion increased the proportion of viable cells. Ketamine alleviated cell shrinkage and increased granularity during the early period, and ameliorated cell swelling during the late reperfusion period. Ketamine may have a valuable effect on amelioration of early and late apoptosis in the astrocytoma cells, even though the exact mechanism remains to be verified.
Anesthetics, Dissociative/*pharmacology ; Annexin A5/pharmacology ; Apoptosis ; Astrocytes/metabolism ; Astrocytoma/*drug therapy/pathology ; Brain/pathology ; Carbonyl Cyanide m-Chlorophenyl Hydrazone/pharmacology ; Cell Line, Tumor ; Cell Size ; Cell Survival ; Central Nervous System/drug effects/pathology ; Enzyme Inhibitors/pharmacology ; Flow Cytometry/*methods ; Humans ; Indicators and Reagents/pharmacology ; Iodoacetates/pharmacology ; Ischemia/pathology ; Ketamine/metabolism/*pharmacology ; Light ; Neurons/metabolism/pathology ; Neutrophils/metabolism ; Perfusion ; Propidium/pharmacology ; Scattering, Radiation ; Time Factors ; Uncoupling Agents/pharmacology