Therapeutic effects of low-intensity transcranial ultrasound on neurological recovery in rat models of MCAO with varying injury severities
Yuyao Lai, Peishan Wu, Xinhan Cao, Mingjun He, Hongmei Wen, Li Luo, Xiaojing Long, Lijie Ren, Yao Wang
Brain Research 2025 · 10.1016/j.brainres.2025.149871
Abstract
Background Low-intensity transcranial ultrasound (LITUS) is a safe, non-invasive neuromodulation method shown to improve neurological function after ischemic stroke in middle cerebral artery occlusion (MCAO) rats models. Given that the degree of severity of ischemic damage may influence treatment outcomes, it is important to investigate the therapeutic performance of LITUS in various injury models to provide a comprehensive understanding to support its clinical application. Methods Sixty adult male SD rats were randomly divided into four groups: Sham (S), MCAO only (M), MCAO + high-intensity transcranial ultrasound (HITUS) injury + LITUS treatment (MHL), and MCAO + LITUS treatment (ML), with 15 rats per group. MCAO models were verified by 9.4 T MRI. LITUS was administered to MHL and ML groups for 20 min daily over 14 days. Behavioral tests, blood biomarkers, and molecular analyses (Western blot, qPCR, immunofluorescence) were used to evaluate neurological function, inflammation, and neurovascular changes. Results LITUS significantly improved neurological, motor, and cognitive functions in MCAO rats with varying injury severities. Treated animals showed better body weight recovery, lower Longa scores, improved motor coordination, and enhanced exploratory and recognition behavior. Mechanistically, LITUS reduced peripheral inflammation, downregulated iNOS expression, and regulated glucose, lipid, and homocysteine levels, supporting systemic homeostasis. It also promoted hematopoiesis and upregulated angiogenic markers (VEGF-A, eNOS, CD31), enhancing vascular regeneration in the ischemic cortex. Furthermore, LITUS activated the BDNF/nNOS signaling pathway, facilitating neurogenesis and neuronal repair. These findings suggest that LITUS exerts multi-target protective effects through coordinated regulation of inflammation, metabolism, angiogenesis, and neuroregeneration, offering strong therapeutic potential for stroke recovery. Conclusion LITUS treatment can improve neurological and motor dysfunction in MCAO rats with varying degrees of injury. The potential underlying mechanism of LITUS is through the regulation of the level of inflammation and promoting angiogenesis and neurogenesis.
Abstract via europepmc.
Exposures
Exposure 1: LITUS after MCAO (ML) and after MCAO plus HITUS injury (MHL groups)
Target: brain — “ipsilateral hemisphere”
Device: other named manufacturer · Green Valley Brain Medical Technology Co., Ltd. · GVBT-1-A001 single-channel stimulator with 20 mm planar transducer ✓
| Waveform | pulsed | |
|---|---|---|
| Fundamental frequency (kHz) | 1,000 | ✓✓✓⚑ |
| Pulse duration (ms) | 0.2 | ✓✓✓ |
| Pulse repetition frequency (Hz) | not reported | |
| Duty cycle (%) | 20 | ✓✓✓⚑ |
| Sonication duration (s) | 1 | ✓✓✓⚑ |
| Free-field pressure (kPa) | not reported | |
|---|---|---|
| Free-field Isppa (W/cm²) | not reported | |
| Free-field Ispta (W/cm²) | not reported | |
| In-situ estimate | measurementsingle value | |
| In-situ pressure (kPa) | not reported | |
| In-situ Isppa (W/cm²) | not reported | |
| In-situ Ispta (W/cm²) | 0.462 | ✓✓✓⚑ |
| Pressure, domain unspecified (kPa) | 930 | ✓✓✓⚑ |
| Isppa, domain unspecified (W/cm²) | 7.7 | ✓✓✓ |
| Ispta, domain unspecified (W/cm²) | 0.77 | ✓✓✓ |
Pulses of 200 us with a duty cycle of 20 %, delivered in cycles repeated every 2 s, each stimulation period lasting 1 s; 20 min daily for 14 consecutive days starting 24 h (ML) or 48 h after HITUS (MHL) after MCAO. A separate high-intensity injury exposure (1 MHz, 20 min, Isppa 27.5 W/cm2, Ispta 3300 mW/cm2) was given to MHL rats 24 h after MCAO to aggravate damage.
Consistency checks: intensity pressure inconsistent unspecified domain.
Flags from extraction
exposures[0].timing.duty_cycle_pct— 20 % duty cycle with 200 us pulses implies a PRF the paper does not state; PRF left not_reported and nothing computed.exposures[0].unspecified_domain.pressure_kpa— 0.93 MPa is called the 'local peak-to-peak acoustic pressure' measured; domain (water or skull) not stated, so placed in unspecified_domain. Isppa 7.70 W/cm2 and Ispta 770 mW/cm2 likewise.exposures[0].in_situ.ispta_w_cm2— Effective Ispta 462 mW/cm2 at the target after a stated 40 % attenuation through rat skull by hydrophone measurement.n_subjects— Group sizes of the two LITUS-treated groups (MHL and ML, 15 each); 60 rats in total across four groups, two of them not sonicated with LITUS. Figures report n = 12 or fewer per group.exposures[0].target.terms— Target not named beyond the ipsilateral hemisphere and the infarcted cortex; planar 20 mm transducer with 8 mm focal depth.exposures[0].timing.sonication_duration_s— Each stimulation period lasts 1 s, repeated every 2 s.anaesthesia— Isoflurane is described for MCAO surgery; anaesthesia during LITUS is not stated.exposures[0].fundamental_frequency_khz— Second exposure (HITUS injury) at the same 1 MHz and target is described in protocol_description rather than as a separate exposure; its stated AMP of 31 Pa is not a pressure that can be used.