Neuroprotective Effect of Ultrasound Neuromodulation on Kainic Acid- Induced Epilepsy in Mice

Junjie Zou, Shasha Yi, Lili Niu, Hui Zhou, Zhengrong Lin, Yibo Wang, Xiaowei Huang, Wen Meng, Yanwu Guo, Lin Qi, Long Meng

IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control 2021 · 10.1109/tuffc.2021.3079628

rodentepilepsybehaviourhistology molecular

Abstract

Preliminary evidence suggests that low-intensity pulsed ultrasound (LIPUS) has neuroprotective effects on ischemic stroke, depression, and other conditions leading to neuronal cell death (e.g., Parkinson's disease). The purpose of this study was to investigate the neuroprotective effects of LIPUS in epileptic mice. Mice were made epileptic through kainic acid (KA) administration and then stimulated with LIPUS. The neuroprotective effect of ultrasound was evaluated by observing the latency, anxiety-like behavior, and levels of proteins related to inflammation, apoptosis, or signaling pathways. The safety of LIPUS was assessed by hematoxylin and eosin (H&E) and Nissl stainings. LIPUS prolonged the latency (Sham: 6.00 ± 0.26 days; 1-kHz pulse repetition frequency (PRF): 7.00 ± 0.31 days), improved the anxiety-like behavior, and inhibited the expression of inflammatory factors and apoptosis-related proteins. In addition, H&E and Nissl staining results confirmed that LIPUS did not damage the brain. These findings suggest that LIPUS has neuroprotective effects in mice with KA-induced epilepsy. LIPUS may offer a new therapeutic approach to epilepsy.

Abstract via europepmc.

Speciesmouse (C57BL/6J)

Subjects5, 7, 10, 5, 5, 3swept animals

Sessions per subject7

Randomisednot reported

Blindingnot reported

Sham / controlinactive transducer

Auditory controlnot reported

Readout timingoffline

Anaesthesiaawake

Readoutsbehaviour, histology molecular — seizure latency (video); elevated plus maze; Western blotting (Bcl-2, Bax, TNF-a, IL-1b, JNK pathway); c-Fos immunohistochemistry; H&E and Nissl staining

Direction of effectmixed or unclearLIPUS prolonged seizure latency (6 vs 7 days), improved EPM anxiety-like behaviour and reduced apoptosis and inflammation markers in kainic acid epileptic mice, while c-Fos expression increased in cortex, CA1 and CA3.

Adverse eventsnone observedH&E and Nissl staining showed no bleeding or tissue damage seven days after stimulation.

Exposures

Exposure 1: LIPUS of left cortex and hippocampus, PRF 1 kHz and 10 Hz

Target: cerebral cortex, hippocampus, CA1, CA3 — “left cortex and hippocampus (including CA1 and CA3)”
Device: custom-built · in-house (Shenzhen Institutes of Advanced Technology) ✓

Pulse timing
Waveform	pulsed
Fundamental frequency (kHz)	3,600	✓✓✓⚑
Pulse duration (ms)	not reported	⚑
Pulse repetition frequency (Hz)	10, 1,000swept	✓✓✓
Duty cycle (%)	50	✓✓✓
Sonication duration (s)	1	✓✓✓

Pressure and intensity, by domain
Free-field pressure (kPa)	not reported
Free-field Isppa (W/cm²)	not reported
Free-field Ispta (W/cm²)	not reported
In-situ estimate	not reported
In-situ pressure (kPa)	not reported
In-situ Isppa (W/cm²)	not reported
In-situ Ispta (W/cm²)	not reported
Pressure, domain unspecified (kPa)	612	✓✓✓⚑
Ispta, domain unspecified (W/cm²)	0.379	✓✓✓⚑

Protocol, in the paper’s words

PRF 1 kHz (or 10 Hz), duty cycle 50%, burst duration (BD) 1 s, interstimulus interval 4 s (text) for 30 min/day for seven consecutive days; the Fig. 1 legend gives ISI = 3 s. Behavioural tests and c-Fos used the 1-kHz PRF only.

Flags from extraction

exposures[0].timing.pulse_duration_ms — 'Burst duration' of 1 s is the train; pulse duration not stated (DC 50% at 1 kHz would imply 0.5 ms but not computed)
exposures[0].timing.protocol_description — Text gives ISI 4 s; Fig. 1 legend states ISI = 3 s
exposures[0].unspecified_domain.pressure_kpa — 0.612 MPa described as negative peak acoustic pressure in the safety discussion; domain not stated (Fig. 1d shows about 65% skull attenuation)
exposures[0].unspecified_domain.ispta_w_cm2 — 378.70 mW/cm2 converted to W/cm2; domain not stated
n_subjects — 76 mice total, split across several assays with different group sizes and a no-KA control group
exposures[0].fundamental_frequency_khz — Fig. 1 legend also lists 3.6 MHz fundamental frequency