Mild repetitive head injury is a serious health problem with long-term negative consequences. Changes in brain neurobiology were assessed with MRI in a model of head injury designed to reflect the human experience. Rats were maintained on a reverse light-dark cycle and head impacted daily at 24 h intervals over three days while fully awake under red light illumination. There was no neuroradiological evidence of brain damage. Rats were imaged for changes in blood brain barrier permeability, edema and gray matter microarchitecture, and resting state functional connectivity. Data were registered to a 3D MRI rat atlas with 173 segmented brain areas providing site-specific information on each imaging modality. Changes in BBB permeability were minimal and localized to the hippocampus and cerebellum. There was evidence of cytotoxic edema in the basal ganglia, thalamus, and cerebellum. There was a global decrease in connectivity and an increase in gliosis in the thalamus, cerebellum, and hippocampus. This study shows a sequelae of neuropathology caused by mild repetitive head injury that is commonly observed in clinical practice using MRI in patients. As such, it may serve as a model for testing the efficacy of new therapeutics using any or all of the measures as biomarkers to assess drug efficacy.
Animals ; Magnetic Resonance Imaging/methods* ; Disease Models, Animal ; Brain/physiopathology* ; Male ; Rats ; Rats, Sprague-Dawley ; Blood-Brain Barrier/diagnostic imaging* ; Multimodal Imaging ; Wakefulness/physiology* ; Craniocerebral Trauma/physiopathology*

OBJECTIVETo study the pattern of blood-brain barrier (BBB) permeability changes during whole brain radiotherapy (WBRT) for metastatic brain tumor.

METHODSTwenty patients with metastatic brain tumors receiving WBRT by 6 MV X-ray underwent (99)mTc-DTPA brain SPECT before and during WBRT (20, 40 Gy) and at 2 weeks after the end of irradiation. A frame of transverse (99)mTc-DTPA brain SPECT image that best displayed the brain metastasis was chosen, and the regions of interest (ROI) were defined in the tumor foci (T), the contralateral normal brain tissue (N) and the background outside the soft tissues around the cranium (B). The radioactive counts of every ROI were measured and the ratios of the total counts (T/B and N/B) before and during WBRT (20 Gy, 40 Gy) and at 2 weeks after the irradiation were calculated.

RESULTSThe average T/B and N/B in the 20 patients with 30 brain metastases was 142.2-/+51.1 and 82.6-/+42.3 before WBRT, 260.3-/+121.5 and 150.7-/+72.5 during 20 Gy WBRT, 251.6-/+118.3 and 161.8-/+68.4 during 40 Gy WBRT, and 250.3-/+117.2 and 158.6-/+73.5 at 2 weeks after the irradiation, respectively. The measurements during WBRT (20 and 40 Gy) and at 2 weeks after the irradiation group underwent no significant variations (P>0.05), but showed significant differences from those before WBRT (P<0.05).

CONCLUSIONSIrradiation causes direct damage of the BBB function, and the permeability of the BBB increases significantly during and within 2 weeks following 20 and 40 Gy WBRT, which provides the optimal time window for interventions with chemotherapy.

Adult ; Aged ; Blood-Brain Barrier ; diagnostic imaging ; physiopathology ; Brain Neoplasms ; diagnostic imaging ; radiotherapy ; secondary ; Capillary Permeability ; physiology ; Cranial Irradiation ; Female ; Humans ; Male ; Middle Aged ; Sodium Pertechnetate Tc 99m ; Tomography, Emission-Computed, Single-Photon

OBJECTIVETo explore the influence of Acorus tatarinowii schott on ultrastructure and permeability of BBB.

METHODThe ultrastructure and permeability of BBB on rats with A. tatarinowii by electron microscope were observed. The even's blue (EB) and sodium phenytoin in brain was determined by UV and HPLC-MS.

RESULTAfter give A. tatarinowii, tight junctions of the endothelial cell opened in cotex, and the concentration of EB and sodium phenytoin in brain are significant increased.

CONCLUSIONA. tatarinowii can increase the permeability of BBB, and show its 'Kaiqiao' effect.

Acorus ; chemistry ; Animals ; Blood-Brain Barrier ; drug effects ; Brain ; cytology ; Cells, Cultured ; Cerebrovascular Circulation ; Drugs, Chinese Herbal ; pharmacology ; Endothelial Cells ; Male ; Microscopy, Electron, Transmission ; Neurons ; diagnostic imaging ; drug effects ; Permeability ; drug effects ; Rats ; Rats, Sprague-Dawley ; Tight Junctions ; drug effects ; ultrastructure ; Ultrasonography