Transcranial ultrasound stimulation relieves depression in mice with chronic restraint stress
Yiyue Zhu, Jiaru He, Canwen Wu, Junwei Wu, Zhongwen Cheng, Yan Chen, Maodan Yuan, Lvming Zeng, Xuanrong Ji
Journal of Neural Engineering 2023, 20, 036011 · 10.1088/1741-2552/ac8bfd
Abstract
Objective. Exhaustion of Serotonin (5-hydroxytryptamine, 5-HT) is a typical cause of the depression disorder's development and progression, including depression-like behaviors. Transcranial ultrasound stimulation (TUS) is an emerging non-invasive neuromodulation technique treating various neurodegenerative diseases. This study aims to investigate whether TUS ameliorates depression-like behaviors by restoring 5-HT levels. Methods. The depression model mice are established by chronic restraint stress (CRS). Ultrasound waves (FF = 1.1 MHz, PRF = 1000 Hz, TBD = 0.5 ms, SD = 1 s, ISI = 1 s, and DC = 50%) were delivered into the dorsal raphe nucleus (DRN) for 30 min per day for 2 weeks. Depression-like behavior changes are evaluated with the sucrose preference and tail suspension tests. Liquid chromatography-mass spectrometry is performed to quantitatively detect the concentration of 5-HT in the DRN to explore its potential mechanism. The effectiveness and safety of TUS were assessed by c-Fos immunofluorescence and hematoxylin and eosin (HE) staining, respectively. Results. Three weeks after CRS, 22 depressive mice models were screened by sucrose preference index (SPI). After 2 weeks of ultrasound stimulation of the DRN (DRN-TUS) in depressive mice, the SPI was increased ( p = 0.1527) and the tail suspension immobility duration was significantly decreased ( p = 0.0038) compared with the non-stimulated group. In addition, TUS significantly enhances the c-Fos ( p = 0.05) positive cells' expression and the 5-HT level ( p = 0.0079) in the DRN. Importantly, HE staining shows no brain tissue damage. Conclusion. These results indicate that DRN-TUS has safely and effectively improved depression-like behaviors including anhedonia and hopelessness, potentially by reversing the depletion of 5-TH. Significance TUS may provide a new perspective on depression therapy, possibly through restoring monoamine levels.
Abstract via europepmc.
Exposures
Exposure 1: Dorsal raphe nucleus (DRN-TUS) in chronic-restraint-stress depression model
Target: raphe nuclei — “dorsal raphe nucleus (DRN)”
Device: custom-built · head-mounted miniature power ultrasonic transducer (custom-built, PZT-4/epoxy 1-3 composite) ✓
| Waveform | pulsed | |
|---|---|---|
| Fundamental frequency (kHz) | 1,100 | ✓✓✓ |
| Pulse duration (ms) | 0.5 | ✓✓✓ |
| Pulse repetition frequency (Hz) | 1,000 | ✓✓✓ |
| Duty cycle (%) | 50pulse duration × PRF gives 50% | ✓✓✓ |
| Sonication duration (s) | 1 | ✓✓✓ |
| Free-field pressure (kPa) | 484 | ✓✓✓ |
|---|---|---|
| Free-field Isppa (W/cm²) | not reported | |
| Free-field Ispta (W/cm²) | not reported | |
| In-situ estimate | measurementsingle value | |
| In-situ pressure (kPa) | 440 | ✓✓✓ |
| In-situ Isppa (W/cm²) | 5.68 | ✓✓✓ |
| In-situ Ispta (W/cm²) | not reported |
1-s sonication trains with a 1-s inter-stimulus interval, delivered for 30 min per day for 2 weeks to the DRN of freely behaving mice; the CRS+Sham group had the transducer output switched off.
Flags from extraction
n_subjects— Seventy mice were used overall, but ultrasound was actually delivered to several different, only partly overlapping cohorts (11 CRS+TUS for behaviour, 3 DRN+TUS for c-Fos immunofluorescence, 5 CRS+TUS for LC-MS, 3 for HE staining); no single total exposed to ultrasound is stated.n_sessions_per_subject— Text states TUS was delivered '30 min per day for 2 weeks', implying about 14 daily sessions, but an explicit session count is never given.randomised— Depressive mice were 'redivided into CRS + Sham and CRS + TUS groups according to the SPI' (matched on sucrose preference index), not by simple randomisation.blinding— Only c-Fos cell counting is described as done by 'double-blind observers'; blinding of TUS/Sham delivery itself is not described.