Preventive Effect of Low Intensity Pulsed Ultrasound against Experimental Cerebral Ischemia/Reperfusion Injury via Apoptosis Reduction and Brain-derived Neurotrophic Factor Induction
Chang-Mu Chen, Cheng-Tien Wu, Ting-Hua Yang, Shing-Hwa Liu, Feng-Yi Yang
Scientific Reports 2018 · 10.1038/s41598-018-23929-8
Abstract
Stroke is known as the top 10 causes of death worldwide. Development of effectively neuroprotective or preventive strategies for ischemia stroke is imperative. For the purpose of stroke prevention, we tested the neuroprotective effects of low-intensity pulsed ultrasound (LIPUS) on ischemic stroke. Adult C57BL/6 mice were used to daily treatment with LIPUS for 5 days on left hemisphere before middle cerebral artery occlusion (MCAO)-induced cerebral ischemia/reperfusion injury. Western blotting and immunohistochemistry were performed to assess the protein expressions of signaling molecules. Pretreatment with LIPUS significantly ameliorated the brain ischemic damage, including the reduction of neurological deficit score, infarct area, histopathological score, and showed a better performance in neurological and behavior functions. LIPUS pretreatment could also significantly decrease the neuronal cell apoptosis and upregulation of apoptosis-related signaling molecules and downregulation of brain-derived neurotrophic factor (BDNF) in brain tissues of MCAO-treated mice. Furthermore, LIPUS significantly prevented the decreased cell viability, the increased caspase-3 cleavage, and the decreased BDNF expression in ischemia/reperfusion-treated microglial cells. These results demonstrate that LIPUS effectively prevented the cerebral ischemia/reperfusion injury through apoptosis reduction and BDNF induction in a MCAO mouse model. The neuroprotective potential of LIPUS may provide a novel preventive strategy for ischemic stroke in high-risk patients.
Abstract via europepmc.
Exposures
Exposure 1: LIPUS pretreatment, mouse left hemisphere
Target: cerebral cortex — “the target region in the injured cortical areas”
Device: Olympus / Panametrics · Panametrics · A392S ✓
| Waveform | pulsed | |
|---|---|---|
| Fundamental frequency (kHz) | 1,000 | ✓✓✓ |
| Pulse duration (ms) | not reportedimplied by duty cycle ÷ PRF: 50 ms (not stated by the paper) | ⚑ |
| Pulse repetition frequency (Hz) | 1 | ✓✓✓ |
| Duty cycle (%) | 5 | ✓✓✓ |
| Sonication duration (s) | not reported | ⚑ |
| 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) | 0.528 | ✓✓✓⚑ |
1.0 MHz focused transducer, 5% duty cycle, repetition frequency 1 Hz; acoustic power 0.51 W; 15 min daily (a 5-minute interval between each sonication) for 5 days before MCAO.
Exposure 2: LIPUS pretreatment of BV-2 microglial cells before hypoxia/reperfusion
Target: cultured glia — “BV2 cells”
Device: not reported
| Waveform | not reported | |
|---|---|---|
| Fundamental frequency (kHz) | not reported | ⚑ |
| Pulse duration (ms) | not reported | |
| Pulse repetition frequency (Hz) | not reported | |
| Duty cycle (%) | not reported | |
| Sonication duration (s) | 900 | ✓✓✓ |
| Free-field pressure (kPa) | not reported | |
|---|---|---|
| Free-field Isppa (W/cm²) | not reported | |
| Free-field Ispta (W/cm²) | not reported | |
| In-situ estimate | not applicable | |
| In-situ pressure (kPa) | not applicable | |
| In-situ Isppa (W/cm²) | not applicable | |
| In-situ Ispta (W/cm²) | not applicable | |
| Ispta, domain unspecified (W/cm²) | 0.11 | ✓✓✓ |
BV2 cells were pre-treated with LIPUS for 15 min (intensity 110 mW/cm2) before hypoxia (6 h) and reperfusion (12 h).
Flags from extraction
n_subjects— Only n = 6 per group is given (Western blot n = 3-5); recorded the LIPUS group size. No total stated.exposures[0].timing.sonication_duration_s— 15 min daily with a 5-minute interval between each sonication; the length of one uninterrupted sonication is unclear, 900 s is the daily total.exposures[0].unspecified_domain.ispta_w_cm2— 528 mW/cm2 converted to 0.528 W/cm2; domain not stated.exposures[1].fundamental_frequency_khz— Frequency for the cell exposure is not stated; paper says only LIPUS 110 mW/cm2 for 15 min.exposures[0].timing.pulse_duration_ms— Pulse duration not stated; paper gives duty cycle 5% and 1 Hz only.exposures[0].device.family— Panametrics A392S transducer mapped to olympus_panametrics.