Low-Intensity Focused Ultrasound Alleviates Spasticity and Increases Expression of the Neuronal K-Cl Cotransporter in the L4–L5 Sections of Rats Following Spinal Cord Injury
Ye-Hui Liao, Mo-Xian Chen, Shao-Chun Chen, Kai-Xuan Luo, Bing Wang, Li-Juan Ao, Yao Liu
Frontiers in Cellular Neuroscience 2022 · 10.3389/fncel.2022.882127
Abstract
Low-intensity focused ultrasound (LIFU) has been shown to provide effective activation of the spinal cord neurocircuits. The aim of this study was to investigate the effects of LIFU in order to alleviate spasticity following spinal cord injury (SCI) by activating the spinal neurocircuits and increasing the expression of the neuronal K-Cl cotransporter KCC 2 . Adult male Sprague Dawley (SD) rats (220-300 g) were randomly divided into a sham control group, a LIFU - group, and a LIFU + group. The mechanical threshold hold (g) was used to evaluate the behavioral characteristics of spasm. Electromyography (EMG) was used to assess activation of the spinal cord neurocircuits and muscle spontaneous contraction. Spasticity was assessed by frequency-dependent depression (FDD). The expression of KCC 2 of the lumbar spinal cord was determined via western blot (WB) and immunofluorescence (IF) staining. The spinal cord neurocircuits were activated by LIFU simulation, which significantly reduced the mechanical threshold (g), FDD, and EMG recordings (s) after 4 weeks of treatment. WB and IF staining both demonstrated that the expression of KCC 2 was reduced in the LIFU - group ( P 2 had significantly increased ( P + group compared with the LIFU - group. Thus, we hypothesized that LIFU treatment can alleviate spasticity effectively and upregulate the expression of KCC 2 in the L4-L5 section of SCI rats.
Abstract via europepmc.
Exposures
Exposure 1: LIFU+ lumbar spinal cord stimulation after SCI
Target: lumbar spinal cord — “lumbar spinal cords”
Device: other named manufacturer · DOBO, China ✓
| Waveform | pulsed | |
|---|---|---|
| Fundamental frequency (kHz) | 4,000 | ✓✓✓ |
| Pulse duration (ms) | not reportedimplied by duty cycle ÷ PRF: 0.625 ms (not stated by the paper) | ⚑ |
| Pulse repetition frequency (Hz) | 800 | ✓✓✓ |
| Duty cycle (%) | 50 | ✓✓✓ |
| Sonication duration (s) | 1,200 | ✓✓✓⚑ |
| 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 | |
| Pressure, domain unspecified (kPa) | 650 | ✓✓✓⚑ |
Sine pulse LIFU to the spinal cord once a day, 20 min each time, starting 1 week after SCI for a total of 4 weeks.
Flags from extraction
n_subjects— 30 rats enrolled in three groups of 10; only the LIFU+ group (n = 10) received ultrasound output (LIFU- had the amplifier off); n_subjects gives the exposed group.exposures[0].unspecified_domain.pressure_kpa— Reported as 'radiation intensity (RI) = 0.65 MPa', a pressure value labelled as intensity; domain not stated.exposures[0].timing.sonication_duration_s— 20 min per session converted to 1200 s; sessions daily for 4 weeks.exposures[0].timing.pulse_duration_ms— Pulse duration not stated; left not_reported.