Low-Intensity Focused Ultrasound Stimulation Ameliorates Working Memory Dysfunctions in Vascular Dementia Rats via Improving Neuronal Environment
Faqi Wang, Qian Wang, Ling Wang, Jing Ren, Xizi Song, Yutao Tian, Chenguang Zheng, Jiajia Yang, Dong Ming
Frontiers in Aging Neuroscience 2022 · 10.3389/fnagi.2022.814560
Abstract
Working memory impairment is one of the remarkable cognitive dysfunctions induced by vascular dementia (VD), and it is necessary to explore an effective treatment. Recently, low-intensity focused ultrasound stimulation (LIFUS) has been found notable neuroprotective effects on some neurological diseases, including VD. However, whether it could ameliorate VD-induced working memory impairment was still not been clarified. The purpose of this study was to address this issue and the underlying mechanism. We established VD rat model using the bilateral common carotid artery occlusion (BCCAO) and applied the LIFUS (center frequency = 0.5 MHz; I spta = 500 mW/cm 2 , 10 mins/day) to bilateral medial prefrontal cortex (mPFC) for 2 weeks since 2 weeks after the surgery. The main results showed that the LIFUS could significantly improve the performance of VD rats in the specific working memory tasks (delayed nonmatch-to-sample task and step-down task), which might be associated with the improved synaptic function. We also found the improvement in the cerebral blood flow (CBF) and reduced neuroinflammation in mPFC after LIFUS treatment indicated by the inhibition of Toll-like receptor (TLR4)/nuclear factor kappa B (NF-κB) pathway and the decrease of proinflammatory cytokines. The amelioration of CBF and neuroinflammation may promote the living environment of the neurons in VD which then contribute to the survival of neurons and the improvement in synaptic function. Taken together, our findings indicate that LIFUS targeted mPFC can effectively ameliorate reward-based spatial working memory and fear working memory dysfunctions induced by VD via restoring the living environment, survivability, and synaptic functions of the neurons in mPFC of VD rats. This study adds to the evidence that LIFUS could become a promising and non-invasive treatment strategy for the clinical treatment of central nervous system diseases related to cognitive impairments in the future.
Abstract via europepmc.
Exposures
Exposure 1: LIFUS to bilateral mPFC in VD rats
Target: ventromedial prefrontal cortex — “bilateral mPFC”
Device: Olympus / Panametrics · Olympus, Tokyo, Japan · V318 ✓
| Waveform | pulsed | |
|---|---|---|
| Fundamental frequency (kHz) | 500 | ✓✓✓ |
| Pulse duration (ms) | 0.3 | ✓✓✓ |
| Pulse repetition frequency (Hz) | 2,000 | ✓✓✓ |
| Duty cycle (%) | not reportedpulse duration × PRF gives 60% | ⚑ |
| Sonication duration (s) | 0.5 | ✓✓✓ |
| 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 | |
| Ispta, domain unspecified (W/cm²) | 0.5 | ✓✓✓⚑ |
0.5 MHz, PRF 2.0 kHz, 150 cycles (0.3 ms tone burst), 0.5 s sonication duration, 2 s interstimulus interval, Ispta 500 mW/cm2; 10 min per side per day to bilateral mPFC under 1% isoflurane, daily for 14 days starting 2 weeks after BCCAO.
Flags from extraction
n_subjects— Group sizes: CON 8, VD 6, VD+LIFUS 6; n = 6 is the LIFUS group. Some figure legends give VD n = 5 for behaviour.exposures[0].timing.duty_cycle_pct— Duty cycle is not stated.exposures[0].unspecified_domain.ispta_w_cm2— 500 mW/cm2 converted to W/cm2; domain not stated.sham_type— CON and VD groups 'underwent the same procedures including anesthesia but without LIFUS'; how sham was produced is not described.exposures[0].device.manufacturer— Transducer is an Olympus V318 0.5 MHz immersion transducer; location given as Tokyo, Japan.