Transcranial focused ultrasound pulsation suppresses pentylenetetrazol induced epilepsy in vivo

Abstract

Background: Epilepsy is a neurological disorder characterized by abnormal neuron discharge, and onethird of epilepsy patients suffer from drug-resistant epilepsy (DRE). The current management for DRE includes epileptogenic lesion resection, disconnection, and neuromodulation. Neuromodulation is achieved through invasive electrical stimulus including deep brain stimulation, vagus nerve stimulation, or responsive neurostimulation (RNS). As an alternative therapy, transcranial focused ultrasound (FUS) can transcranially and non-invasively modulate neuron activity. Objective: This study seeks to verify the use of FUS pulsations to suppress spikes in an acute epileptic small-animal model, and to investigate possible biological mechanisms by which FUS pulsations interfere with epileptic neuronal activity. Methods: The study used a total of 76 Sprague-Dawley rats. For the epilepsy model, rats were administered pentylenetetrazol (PTZ) to induce acute epileptic-like abnormal neuron discharges, followed by FUS exposure. Various ultrasound parameters were set to test the epilepsy-suppressing effect, while concurrently monitoring and analyzing electroencephalogram (EEG) signals. Animal behavior was monitored and histological examinations were conducted to evaluate the hazard posed by ultrasound exposure and the expression of neuronal activity markers. Western blotting was used to evaluate the correlation between FUS-induced epileptic suppression and the PI3K-mTOR signaling pathway. Results: We observed that FUS pulsations effectively suppressed epileptic activity and observed EEG spectrum oscillations; the spike-suppressing effect depended on the selection of ultrasound parameters and highly correlated with FUS exposure level. Expression level changes of c-Fos and GAD65 were confirmed in the cortex and hippocampus, indicating that FUS pulsations deactivated excitatory cells and activated GABAergic terminals. No tissue damage, inflammatory response, or behavioral abnormalities were observed in rats treated with FUS under these exposure parameters. We also found that the FUS pulsations down-regulated the S6 phosphorylation and decreased pAKT expression. Conclusion: Our results suggest that pulsed FUS exposure effectively suppresses epileptic spikes in an acute epilepsy animal model, and finds that ultrasound pulsation interferes with neuronal activity and affects the PTZ-induced PI3K-Akt-mTOR pathway, which might help explain the mechanism underlying ultrasound-related epileptic spike control.

Modulation of EEG Frequency Characteristics by Low-Intensity Focused Ultrasound Stimulation in a Pentylenetetrazol-Induced Epilepsy Model

“…C-Fos is a factor related to neuronal excitation in contrast to GAD65, which indicates inhibition of neuronal activity. The decreased c-Fos factor and increased GAD65 factor during LIFUS found in our study indicated that LIFUS effectively inhibited seizure activity by affecting GABAergic synapses [9].…”

“…Hakimova et al showed that the recurrence time of seizure increased by pulsed ultrasound stimulation in mouse model of mesial temporal lobe epilepsy induced by kainic acid, and social interaction scores were higher for mice with stimulation than for mice without stimulation in the behavioral test. Chen et al investigated effective LIFUS parameters in rats with epilepsy induced by PTZ and demonstrated that LIFUS inhibited epileptic seizure by regulating pAKT, S6, and pI3K-Akt-mTOR pathways [9][10][11][12]. In previous studies, only the number of epileptic spikes and epileptiform activity in the electroencephalogram (EEG) were analyzed [10,12].…”

Safety of focused ultrasound neuromodulation in humans with temporal lobe epilepsy

“…Stimulating through cortex, hippocampus, and thalamus, Chen and colleagues were again able to suppress acute EEG spikes in rats with acute epilepsy using tFUS [22]. The safety of tFUS in human epilepsy, however, has yet to be demonstrated.…”

MicroRNA 223 Targeting ATG16L1 Affects Microglial Autophagy in the Kainic Acid Model of Temporal Lobe Epilepsy

“…Epileptic spikes were counted by optimizing the automated seizure detection algorithm in AcqKnowledge 4.2 (Biopac System, Goleta, CA, USA) during 2 h in mice after KA or saline injection and treated with antagomir 223 or antagomir-NC. Spikes were defined as a sharp deflection with an amplitude more than 2–5 times the background activity and lasting 40–60 ms ( 20 ).…”