Low-intensity focused ultrasound stimulation promotes stroke recovery via astrocytic HMGB1 and CAMK2N1 in mice
Lin Qi, Cheng Wang, Lidong Deng, Jia-Ji Pan, Qian Suo, Shengju Wu, Lin Cai, Xudong Shi, Junfeng Sun, Yongting Wang, Yaohui Tang, Weibao Qiu, Guo-Yuan Yang, Jixian Wang, Zhijun Zhang
Stroke and Vascular Neurology 2024, 9, 505-518 · 10.1136/svn-2023-002614
Abstract
Background Low-intensity focused ultrasound stimulation (LIFUS) has been developed to enhance neurological repair and remodelling during the late acute stage of ischaemic stroke in rodents. However, the cellular and molecular mechanisms of neurological repair and remodelling after LIFUS in ischaemic stroke are unclear. Methods Ultrasound stimulation was treated in adult male mice 7 days after transient middle cerebral artery occlusion. Angiogenesis was measured by laser speckle imaging and histological analyses. Electromyography and fibre photometry records were used for synaptogenesis. Brain atrophy volume and neurobehaviour were assessed 0-14 days after ischaemia. iTRAQ proteomic analysis was performed to explore the differentially expressed protein. scRNA-seq was used for subcluster analysis of astrocytes. Fluorescence in situ hybridisation and Western blot detected the expression of HMGB1 and CAMK2N1. Results Optimal ultrasound stimulation increased cerebral blood flow, and improved neurobehavioural outcomes in ischaemic mice (p Conclusion Our results demonstrated that LIFUS promoted angiogenesis and synaptogenesis after focal cerebral ischaemia by upregulating HMGB1 and downregulating CAMK2N1 in a subcluster of astrocytes, suggesting that LIFUS activated specific astrocyte subcluster could be a key target for ischaemic brain therapy.
Abstract via europepmc.
Exposures
Exposure 1: LIFUS to ipsilateral hemisphere after MCAO
Target: hemisphere unspecified — “ipsilateral hemisphere (perifocal region of MCAO territory)”
Device: custom-built · Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences · Ultrasound Neurostimulation System ✓
| Waveform | pulsed | |
|---|---|---|
| Fundamental frequency (kHz) | 500 | ✓✓✓ |
| Pulse duration (ms) | not reportedimplied by duty cycle ÷ PRF: 0.5 ms (not stated by the paper) | |
| Pulse repetition frequency (Hz) | 1,000 | ✓✓✓⚑ |
| Duty cycle (%) | 50 | ✓✓✓ |
| Sonication duration (s) | 0.3 | ✓✓✓⚑ |
| 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) | 0.022, 0.101, 0.201swept | ✓✓✓⚑ |
500 kHz pulse repetition frequency (PRF), 300 ms sonication duration (SD) and 50% duty cycle (DC) were used across all the ultrasound experiments (figure 1D). Separately, ultrasonic intensity (22, 101, 201 mW/cm2) and total stimulation duration (1, 3, 5, or 10 min, every other day) were varied to optimise the treatment; 3 min at 101 mW/cm2 every other day (US1) was chosen as the optimal protocol starting 7 days after MCAO.
Flags from extraction
exposures[0].timing.pulse_repetition_frequency_hz— Main text states PRF = 500 kHz (identical to the 500 kHz carrier frequency, likely an error), while the Figure 1D legend states 'PRF was 1 kHz and 1/PRF was 1 s' (internally inconsistent, since 1 kHz implies a 1 ms period, not 1 s). The two statements conflict and neither could be confirmed, so PRF is left not_reported.exposures[0].timing.sonication_duration_s— The paper labels 300 ms as 'sonication duration (SD)' in the pulse-diagram parameters, but separately reports total per-session ultrasound exposure durations of 1, 3, 5, or 10 minutes; it is unclear which corresponds to the schema's one-uninterrupted-train duration, so left not_reported and both durations are described in protocol_description.n_subjects— Paper reports many different per-experiment group sizes (n=120 total mice allocated; n=12/group for behaviour and imaging; ~n=4/group for other assays; n=3-7 in various figure panels) without stating a single total number of animals exposed to ultrasound.n_sessions_per_subject— Ultrasound was given 'every other day' from day 7 post-MCAO, but the total number of stimulation sessions per animal is not explicitly stated.sham_type— The comparison for the ultrasound intervention is an untreated (no-device) stroke group (IS); the paper does not describe a device-based sham (e.g., powered-off transducer) for these experiments, so no listed vocabulary term fits precisely.exposures[0].unspecified_domain.ispta_w_cm2— Paper does not state whether the 22/101/201 mW/cm2 ultrasonic intensity values are free-field or in-situ; domain left unspecified.