Protective Effect of Low-Intensity Pulsed Ultrasound on Memory Impairment and Brain Damage in a Rat Model of Vascular Dementia
Sin-Luo Huang, Chi-Wei Chang, Yi-Hsuan Lee, Feng-Yi Yang
Radiology 2017, 282, 113-122 · 10.1148/radiol.2016160095
Abstract
Purpose To investigate the neuroprotective effects of low-intensity pulsed (LIP) ultrasound on memory impairment and central nervous system injury in a rat model of vascular dementia. Materials and Methods All animal experiments were approved by the animal care and use committee and adhered to experimental animal care guidelines. A 1.0-MHz focused ultrasound transducer was used to stimulate the brain noninvasively with 50-msec bursts at a 5% duty cycle, repetition frequency of 1 Hz, and spatial peak temporal average intensity of 528 mW/cm 2 . LIP ultrasound treatment was performed daily with triple sonications in each hemisphere. The duration of each sonicaton was 5 minutes, with a 5-minute interval between each sonication. Permanent bilateral common carotid artery occlusion (BCCAO) was used as a model of vascular dementia. After 2 weeks of LIP ultrasound, neuroprotective effects of LIP ultrasound were evaluated with behavioral analysis, including the passive avoidance task and elevated plus maze. Myelin content was detected with carbon 11 ( 11 C) Pittsburgh compound B (PIB). Brain sections were stained with hematoxylin-eosin and Luxol fast blue. Two-way analysis of variance and Student t test were used for statistical analyses, with a significance level of .05. Results Protein expressions of brain-derived neurotrophic factor (BDNF) in the BCCAO rats treated with LIP ultrasound were significantly higher than those in BCCAO rats (1.1 ± 0.0 vs 0.8 ± 0.1, P 11 C PIB accumulation in the BCCAO rats treated with LIP ultrasound was significantly (P © RSNA, 2016.
Abstract via europepmc.
Exposures
Exposure 1: LIP ultrasound treatment of the brain (sham/healthy and BCCAO rats)
Target: brain — “the desired region (3.0 mm posterior and 2.5 mm lateral to the bregma) of the brain”
Device: Olympus / Panametrics · Panametrics · A392S ✓
| Waveform | pulsed | |
|---|---|---|
| Fundamental frequency (kHz) | 1,000 | ✓✓✓ |
| Pulse duration (ms) | 50 | ✓✓✓ |
| Pulse repetition frequency (Hz) | 1 | ✓✓✓ |
| Duty cycle (%) | 5pulse duration × PRF gives 5% | ✓✓✓ |
| Sonication duration (s) | 300 | ✓✓✓ |
| Free-field pressure (kPa) | not reported | |
|---|---|---|
| Free-field Isppa (W/cm²) | not reported | |
| Free-field Ispta (W/cm²) | 0.528 | ✓✓✓ |
| 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 |
Each rat hemisphere was treated with LIP ultrasound daily with triple sonications. The duration of each sonication was 5 minutes, with a 5-minute interval between each sonication. Animals in the LIP ultrasound group were treated with LIP ultrasound daily for 14 days (in the BCCAO+LIP ultrasound group, starting 2 weeks after BCCAO surgery).
Flags from extraction
n_subjects— Sample sizes vary by experiment/readout (n=3 for histology, n=4 for biochemical/PET biodistribution, n=8 for behavioural tests); no single total of ultrasound-exposed animals is stated.blinding— Paper states quantification of BDNF/myelin staining was performed 'in a blinded manner' (outcome assessment blinding); no statement about blinding of treatment allocation or behavioural testing.anaesthesia— Isoflurane anaesthesia is described for BCCAO surgery and PET imaging, but the paper does not state whether animals were anaesthetised during the daily LIP ultrasound stimulation sessions themselves.