Data_Sheet_1_Transcranial burst electrical stimulation contributes to neuromodulatory effects in the rat motor cortex.docx

Background and objectiveTranscranial Burst Electrical Stimulation (tBES) is an innovative non-invasive brain stimulation technique that combines direct current (DC) and theta burst stimulation (TBS) for brain neuromodulation. It has been suggested that the tBES protocol may efficiently induce neuroplasticity. However, few studies have systematically tested neuromodulatory effects and underlying neurophysiological mechanisms by manipulating the polarity of DC and TBS patterns. This study aimed to develop the platform and assess neuromodulatory effects and neuronal activity changes following tBES.MethodsFive groups of rats were exposed to anodal DC combined with intermittent TBS (tBES+), cathodal DC combined with continuous TBS (tBES−), anodal and cathodal transcranial direct current stimulation (tDCS+ and tDCS−), and sham groups. The neuromodulatory effects of each stimulation on motor cortical excitability were analyzed by motor-evoked potentials (MEPs) changes. We also investigated the effects of tBES on both excitatory and inhibitory neural biomarkers. We specifically examined c-Fos and glutamic acid decarboxylase (GAD-65) using immunohistochemistry staining techniques. Additionally, we evaluated the safety of tBES by analyzing glial fibrillary acidic protein (GFAP) expression.ResultsOur findings demonstrated significant impacts of tBES on motor cortical excitability up to 30 min post-stimulation. Specifically, MEPs significantly increased after tBES (+) compared to pre-stimulation (p = 0.026) and sham condition (p = 0.025). Conversely, tBES (−) led to a notable decrease in MEPs relative to baseline (p = 0.04) and sham condition (p = 0.048). Although tBES showed a more favorable neuromodulatory effect than tDCS, statistical analysis revealed no significant differences between these two groups (p > 0.05). Additionally, tBES (+) exhibited a significant activation of excitatory neurons, indicated by increased c-Fos expression (p  0.05), indicating that tBES did not induce neural injury in the stimulated regions.ConclusionOur study indicates that tBES effectively modulates motor cortical excitability. This research significantly contributes to a better understanding of the neuromodulatory effects of tBES, and could provide valuable evidence for its potential clinical applications in treating neurological disorders.</p

Pharmacodynamic and Therapeutic Investigation of Focused Ultrasound-Induced Blood-Brain Barrier Opening for Enhanced Temozolomide Delivery in Glioma Treatment

<div><p>Focused ultrasound (FUS) exposure with the presence of microbubbles has been shown to transiently open the blood-brain barrier (BBB), and thus has potential to enhance the delivery of various kinds of therapeutic agents into brain tumors. The purpose of this study was to assess the preclinical therapeutic efficacy of FUS-BBB opening for enhanced temozolomide (TMZ) delivery in glioma treatment. FUS exposure with microbubbles was delivered to open the BBB of nude mice that were either normal or implanted with U87 human glioma cells. Different TMZ dose regimens were tested, ranging from 2.5 to 25 mg/kg. Plasma and brain samples were obtained at different time-points ranging from 0.5 to 4 hours, and the TMZ concentration within samples was quantitated via a developed LC-MS/MS procedure. Tumor progression was followed with T2-MRI, and animal survival and brain tissue histology were conducted. Results demonstrated that FUS-BBB opening caused the local TMZ accumulation in the brain to increase from 6.98 to 19 ng/mg. TMZ degradation time in the tumor core was found to increase from 1.02 to 1.56 hours. Improved tumor progression and animal survival were found at different TMZ doses (up to 15% and 30%, respectively). In conclusion, this study provides preclinical evidence that FUS-BBB opening increases the local concentration of TMZ to improve the control of tumor progression and animal survival, suggesting the potential for clinical application to improve current brain tumor treatment.</p></div

Efficacy of various treatment protocols for induced brain tumors in mice.

<p>Increase in median survival time (IST_median; in %), increase in mean survival time (IST_mean; in %), <i>p</i>-values are all relative to the control group.</p><p>Efficacy of various treatment protocols for induced brain tumors in mice.</p

Conceptual diagrams and time course for experimental approach using focused ultrasound (FUS)-induced blood-brain barrier opening to enhance temozolomide (TMZ) delivery in a glioma animal model.

<p>Conceptual diagrams and time course for experimental approach using focused ultrasound (FUS)-induced blood-brain barrier opening to enhance temozolomide (TMZ) delivery in a glioma animal model.</p

Kaplan–Meier plot demonstrating animal survival in experimental group 3.

<p>Kaplan–Meier plot demonstrating animal survival in experimental group 3.</p

LC-MS/MS measurement of TMZ concentration (µg/mg) in FUS-BBB opened and contralateral brains (n = 6).

<p>LC-MS/MS measurement of TMZ concentration (µg/mg) in FUS-BBB opened and contralateral brains (n = 6).</p

Representative T2-weighted MR images to monitor brain tumor progression weekly from days 10 to 38 in each of the subgroups of experimental group 3 (groups: sham control, FUS-BBB only, TMZ of 2.5 mg/kg (per day for 3 days) without and with FUS-BBB opening, TMZ of 25 mg/kg (per day for 3 days). Bar = 0.5 mm.

<p>Representative T2-weighted MR images to monitor brain tumor progression weekly from days 10 to 38 in each of the subgroups of experimental group 3 (groups: sham control, FUS-BBB only, TMZ of 2.5 mg/kg (per day for 3 days) without and with FUS-BBB opening, TMZ of 25 mg/kg (per day for 3 days). Bar  = 0.5 mm.</p

Concentration-time profile of TMZ measurements in brain tumor and contralateral brain tissue.

<p>(a, b) TMZ alone, tumor and contralateral tissue; (c, d) TMZ combined with FUS-BBB opening, tumor and contralateral tissue. A TMZ dose of 50 mg/kg was administered, and a FUS exposure power of 2 W was delivered in the TMZ + FUS animal groups. Data are presented for individual measurements with the mean values from each group, and dashed line represents the corresponding progression curve estimation.</p

Concentration-time profile of TMZ measurements in plasma.

<p>(a) TMZ alone; (b) TMZ combined with FUS-BBB opening. A TMZ dose of 50 mg/kg was administered, and a FUS exposure power of 2 W was delivered in the TMZ + FUS animal group. Data are presented for individual measurements with the mean values for each group, and dashed line represents the corresponding progression curve estimation.</p

Representative Evans Blue (EB) dye staining in animal brains after FUS-BBB opening.

<p>(a) Top view; (b) cross-sectional view; (c, d) HE stains of FUS exposure and contralateral brains. White dashed contour  =  FUS-BBB-opened regions; Red dashed contour  =  tumor region. Bar  = 50 µm.</p