Effect Of Low-intensity Ultrasound Stimulation Research Articles

Low-intensity ultrasound stimulation modulates cortical neurovascular coupling in an attention deficit hyperactivity disorder rat model.

Attention deficit hyperactivity disorder is accompanied by changes in cranial nerve function and cerebral blood flow (CBF). Low-intensity ultrasound stimulation can modulate brain neural activity in attention deficit hyperactivity disorder. However, to date, the modulatory effects of low-intensity ultrasound stimulation on CBF and neurovascular coupling in attention deficit hyperactivity disorder have not been reported. To address this question, Sprague-Dawley, Wistar-Kyoto, and spontaneously hypertensive (attention deficit hyperactivity disorder (ADHD) rat model) rats were divided into the control and low-intensity ultrasound stimulation (LIUS) groups. Cortical electrical stimulation was used to induce cortical excitability in different types of rats, and a penetrable laser speckle contrast imaging (LSCI) system and electrodes were used to evaluate the electrical stimulation-induced CBF, cortical excitability, and neurovascular coupling in free-moving rats. The CBF, cortical excitability, and neurovascular coupling (NVC) under cortical electrical stimulation in the attention deficit hyperactivity disorder rats were significantly different from those in the Sprague-Dawley and Wistar-Kyoto rats. We also found that low-intensity ultrasound stimulation significantly interfered with the cortical excitability and neurovascular coupling induced by cortical electrical stimulation in rats with attention deficit hyperactivity disorder. Our findings suggest that neurovascular coupling is a potential biomarker for attention deficit hyperactivity disorder. Furthermore, low-intensity ultrasound stimulation can improve abnormal brain function in attention deficit hyperactivity disorder and lay a research foundation for its application in the clinical treatment of attention deficit hyperactivity disorder.

Preventive and Therapeutic Effects of Low-Intensity Ultrasound Stimulation on Migraine in Rats.

This study sought to systematically evaluate the prophylactic and therapeutic effects of low-intensity transcranial ultrasound stimulation on migraine in rats. We used video recordings to assess the head scratching behavior and laser speckle contrast imaging to record the changes in cerebral blood flow velocity of freely moving rats in a healthy group, migraine group, migraine group with ultrasound prevention, and migraine group with ultrasound therapy. Results demonstrated that (1) head scratching during migraine attacks in rats was accompanied by an decrease in cerebral blood flow; (2) both ultrasound prevention and therapy significantly reduced the number of head scratches but did not reduce the cerebral blood flow velocity; and (3) the number of head scratches in the ultrasound stimulation groups was not affected by the auditory effect. These results reveal that low-intensity ultrasound has the potential to be used clinically in the prevention and therapeutic treatment of migraine.

Effect of Low-Intensity Ultrasound Stimulation on the Attenuation of Mechanical Properties of Fibrous Tissue

The effect of low intensity ultrasound on the mechanical properties of soft tissue such as tendon is not well understood. In this study, the rat tail tendons were used to determine the effect of ultrasound on the mechanical properties of tendon fiber. Twenty two collagen fibers were extracted from rat tail tendon fibers. The collagen fibers were separated into two groups, one with and one without ultrasound stimulations. Cyclic loading test within toe-region of collagen fibers were conducted in degassed water. The intensity and frequency of the ultrasound was 70 mW/cm2 and 1 MHz respectively. The results showed the tangent modulus of the collagen fiber in the ultrasound group was reduced from 300 MPa to 250 MPa in comparison to the control group. Further mechanical test and analysis of mathematical model should be done to understand the mechanism and reaction between ultrasound and the stiffness of the soft tissue.

The Evaluation of the Healing Rate of Subtalar Arthrodeses, Part 2: The Effect of Low-Intensity Ultrasound Stimulation

Arthrodeses of hindfoot joints is commonly used to treat a multitude of painful conditions and deformity. Use of adjuvant low-intensity ultrasound bone stimulation has demonstrated promising results in the treatment of acute fractures and fracture nonunions. The purpose of this 12-month prospective study was to evaluate the healing rate and clinical results of patients undergoing primary subtalar arthrodeses with adjuvant low-intensity ultrasound bone stimulation. Fifteen consecutive patients participated in the study. Routine radiographs and CT scans were obtained, and clinical outcomes gathered. The clinical and radiographic data were compared to a similar cohort of patients previously reported on that had not received ultrasound bone stimulation. The patients who received ultrasound bone stimulation showed a statistically significant faster healing rate on plain radiographs at 9 weeks (p = 0.034) and CT scan at 12 weeks (p = 0.017). A 100% fusion rate was noted. The American Orthopaedic Foot and Ankle Society (AOFAS) ankle and hindfoot score was also improved at 12 months postoperatively, a finding that was statistically significant (p = 0.026). This is the first paper, to our knowledge, to prospectively evaluate ultrasound bone stimulation in primary hindfoot arthrodesis patients. We were able to show significantly improved radiographic as well as clinical outcomes compared with a similar cohort of patients who did not receive adjuvant ultrasound stimulation. We believe that low-intensity ultrasound bone stimulation is indicated in primary hindfoot fusions, particularly in those patients at higher risk for nonunion.

Can ultrasound counteract bone loss? Effect of low-intensity ultrasound stimulation on a model of osteoclastic precursor

The aim of the present work is to determine whether mechanical stress caused by ultrasound (US) exposure affects osteoclastic precursor cells, thus addressing the hypothesis that mechanical strain-induced perturbation of preosteoclastic cell machinery can contribute to the occurrence of bone turnover alterations. Moreover, cell cytoskeleton was studied because of its supposed involvement in cell mechanotransduction. Our experimental model was the FLG 29.1 human cell line, previously characterized as an osteoclastic precursor model. Cell proliferation was quantified by trypan blue exclusion assay. Cell morpho-functional state was monitored by multispectral imaging autofluorescence microscopy. The expression of cytoskeletal components and markers of proliferation (Ki67) and osteoclastic differentiation (RANK) was analysed by immunocytochemistry. The findings demonstrated that US stimulation affects FLG 29.1 cell growth, depresses the expression of cytoskeletal components and markers of proliferation and differentiation, induces cell damage, thus supporting the hypothesis that US exposure inhibits osteoclastogenesis. These results have been compared with those obtained previously by exposure of FLG 29.1 cells to modelled hypogravity conditions. Finally, the possibility to utilize US stimulation for counteracting osteoporosis has been discussed.

Effect of Low-Intensity Ultrasound Stimulation on Consolidation of the Regenerate Zone in a Rat Model of Distraction Osteogenesis

This study was performed to explore the tissue-level changes in mineralization caused by low-intensity ultrasound stimulation after distraction osteogenesis. Unilateral femoral lengthenings (7 mm) were performed on 34 male Sprague-Dawley rats. Half of the animals received daily ultrasound stimulation for 5 weeks; the remaining animals received sham treatments. Healing was assessed with serial radiographs, quantitative micro-computed tomography, and biomechanical testing. Twenty-one animals were evaluated at the conclusion of the study (9 experimental, 12 control). Radiographically, healing of the ultrasound-treated bones preceded that of the sham-treated bones by approximately 1 week. Bone volume fraction and trabecular bone pattern factor were significantly higher in the ultrasound-treated animals, but there were no significant differences in bone mineral content or bone mineral density. The ultrasound-treated femurs were 20% stiffer and 33% stronger than the control femurs, but the differences were not statistically significant. These findings suggest that pulsed, low-intensity ultrasound matures the regenerate by altering the microarchitecture of the newly formed bone.

In vitro effects of low-intensity ultrasound stimulation on the bone cells.

Mechanical perturbations serve as extracellular signals to a variety of cells, including bone cells. Low-intensity pulsed ultrasound produces significant multifunctional effects that are directly relevant to bone formation and resorption. Ultrasound stimulation has been shown to accelerate bone-defect healing and trabecular bone regeneration. In this study, we use an in vitro bone cell culture model to investigate the effect of low-intensity pulsed ultrasound. The rat alveolar mononuclear cell-calvaria osteoblast coculture system was used in this study. Before treatment, the bone cells were cultured for 3 days to facilitate their attachment and differentiation. Then, ultrasound exposure (frequency = 1 MHz, intensity = 0.068 W/cm(2)) or sham exposure for 20 min per day was applied until the end of the experiment. Half of the culture media were obtained on the 4th, 5th, 6th, 7th, 8th, 9th, and 10th days for the analysis of cytokines and biochemical parameters. At the end of the experiment, cells were fixed and stained for identification and quantification of the osteoblast and osteoclast cells. After low-intensity pulse ultrasound stimulation, the osteoblast cell counts were significantly increased, whereas the osteoclast cell counts were significantly decreased. The total alkaline phosphatase amount in the culture medium was increased after 7 days of ultrasound stimulation, and tumor necrosis factor-alpha in ultrasound-stimulated bone cells was significantly increased after the 7th day of culture and reached 474.77% of the control medium on the 10th day of culture. The results of this study suggest that low-intensity ultrasound treatment may have a stimulatory effect on bone-healing processes.