Form Of Mechanical Stimulation Research Articles

Low-intensity pulsed ultrasound promotes skeletal muscle regeneration via modulating the inflammatory immune microenvironment.

Background: Low-intensity pulsed ultrasound (LIPUS, a form of mechanical stimulation) can promote skeletal muscle functional repair, but a lack of mechanistic understanding of its relationship and tissue regeneration limits progress in this field. We investigated the hypothesis that specific energy levels of LIPUS mediates skeletal muscle regeneration by modulating the inflammatory microenvironment. Methods: To address these gaps, LIPUS irritation was applied in vivo for 5 min at two different intensities (30mW/cm2 and 60mW/cm2) in next 7 consecutive days, and the treatment begun at 24h after air drop-induced contusion injury. In vitro experiments, LIPUS irritation was applied at three different intensities (30mW/cm2, 45mW/cm2, and 60mW/cm2) for 2 times 24h after introduction of LPS in RAW264.7. Then, we comprehensively assessed the functional and histological parameters of skeletal muscle injury in mice and the phenotype shifting in macrophages through molecular biological methods and immunofluorescence analysis both in vivo and in vitro. Results: We reported that LIPUS therapy at intensity of 60mW/cm2 exhibited the most significant differences in functional recovery of contusion-injured muscle in mice. The comprehensive functional tests and histological analysis in vivo indirectly and directly proved the effectiveness of LIPUS for muscle recovery. Through biological methods and immunofluorescence analysis both in vivo and in vitro, we found that this improvement was attributable in part to the clearance of M1 macrophages populations and the increase in M2 subtypes with the change of macrophage-mediated factors. Depletion of macrophages in vivo eliminated the therapeutic effects of LIPUS, indicating that improvement in muscle function was the result of M2-shifted macrophage polarization. Moreover, the M2-inducing effects of LIPUS were proved partially through the WNT pathway by upregulating FZD5 expression and enhancing β-catenin nuclear translocation in macrophages both in vitro and in vivo. The inhibition and augment of WNT pathway in vitro further verified our results. Conclusion: LIPUS at intensity of 60mW/cm2 could significantly promoted skeletal muscle regeneration through shifting macrophage phenotype from M1 to M2. The ability of LIPUS to direct macrophage polarization may be a beneficial target in the clinical treatment of many injuries and inflammatory diseases.

Effect of Instrument-Assisted Soft Tissue Mobilization on Exercise-Induced Muscle Damage and Fibrotic Factor: A Randomized Controlled Trial

Background and ObjectiveThe instrument-assisted soft tissue mobilization (IASTM) is a form of mechanical stimulation. This treatment is known to provide an effective way to improve muscle function and attenuate muscle pain. However, limited study showed the effect of the IASTM on acute condition such as exercise-induced muscle damage. This study aimed to examine the effects of IASTM on exercise-induced muscle dam-age and fibrotic factor. Material and MethodsSixteen healthy male college students were randomly assigned to IASTM (n=8) and control (n=8). After performing two sets of 25 eccentric contractions of elbow flexors, IASTM was applied for 8 min immediately and 48 h after exercise. Maximal isometric strength (MIS), muscle soreness, and creatine kinase (CK) activity were measured as indicators of muscle damage. Transforming growth factor-β1 (TGF-β1) levels were assessed as a fibrotic factor. ResultsThe recovery of MIS was faster (control vs. IASTM: 96 h: 60.7% ± 7.9% vs. 89.1% ± 10.4%, P 0.05). ConclusionIASTM may be an effective method for reducing scar tissue and restoring muscle function quickly after exercise-induced muscle damage.

Thigmomorphogenesis and biomechanical responses of shade-grown Serianthes nelsonii plants to stem flexure

ABSTRACTThe influences of stem flexure on shade-grown Serianthes nelsonii Merr. stem growth and strength were determined in a container nursery setting. Treated stems were bent 90° two times daily for a 14 wk nursery production period. Plant height, internode length, and slenderness were decreased by stem flexure when compared with control plants that received no flexure. Two force-displacement tests revealed stem strength was increased by the flexure treatment. Control plants exhibited undesirable lean of the main stem, and 1 hr of wind stress further increased the angle of lean. Treated plants were close to orthotropic and the wind stress did not change the stem lean. Results indicate stem flexure is a reliable method for increasing the quality of shade-grown S. nelsonii plants and some form of mechanical stimulation should be added to nursery production protocols for the species.

The effects of low-intensity pulsed ultrasound on fresh fracture: A meta-analysis.

Low-intensity pulsed ultrasonography (LIPUS) is a form of mechanical stimulation that is delivered via a special device to the fracture site for the acceleration of fracture healing. We conducted a meta-analysis to assess the effect of LIPUS for fresh fractures in adults. MEDLINE, EMBASE and the Cochrane Library searched between Jan 1980 and Nov 2016. Studies should be quasi-randomized and randomized controlled trials (RCTs) comparing treatment with LIPUS to placebo or no treatment in adults with fresh fractures, reporting outcomes such as function; time to union; delayed union or non-union. Summary standard mean difference (SMD) and the risk ratio (RR) with their 95% confidence interval (CI) calculated with a random effects model. I statistic was used to assess the heterogeneity. Risk of bias was assessed by the Cochrane risk-of-bias tool. The GRADE system was used to evaluate the evidence quality. A total of 12 trials with 1099 patients were included. The pooled results showed that LIPUS significantly reduced the time to fracture union (SMD: 0.65, 95% CI: 1.13 to 0.17), improved the quality of life (SMD: 0.20, 95% CI: 0.03-0.37) without affecting the time to full weight bearing (SMD: 0.76, 95% CI: 1.92 to 0.4), the time to return to work (SMD: 0.06, 95% CI: 0.14 to 0.27), or the incidence rate of delayed union and nonunion (RR: 1.02, 95% CI: 0.60-1.74). Moderate-to-high quality evidence shows that LIPUS treatment reduces the time to fracture union and improves the quality of life without affecting functional recovery and incident rate of delayed union and nonunion, suggesting that LIPUS treatment may be a good treatment modality for adults with fresh fractures. However, there are some methodological limitations in the eligible trials, further studies are needed to determine the clinical circumstances under which LIPUS is truly valid and to examine the optimal approach for the use of this adjunctive therapy.

Algal Cell Response to Pulsed Waved Stimulation and Its Application to Increase Algal Lipid Production

Generating renewable energy while sequestering CO2 using algae has recently attracted significant research attention, mostly directing towards biological methods such as systems biology, genetic engineering and bio-refining for optimizing algae strains. Other approaches focus on chemical screening to adjust culture conditions or culture media. We report for the first time the physiological changes of algal cells in response to a novel form of mechanical stimulation, or a pulsed wave at the frequency of 1.5 MHz and the duty cycle of 20%. We studied how the pulsed wave can further increase algal lipid production on top of existing biological and chemical methods. Two commonly used algal strains, fresh-water Chlorella vulgaris and seawater Tetraselmis chuii, were selected. We have performed the tests in shake flasks and 1 L spinner-flask bioreactors. Conventional Gravimetric measurements show that up to 20% increase for algal lipid could be achieved after 8 days of stimulation. The total electricity cost needed for the stimulations in a one-liter bioreactor is only one-tenth of a US penny. Gas liquid chromatography shows that the fatty acid composition remains unchanged after pulsed-wave stimulation. Scanning electron microscope results also suggest that pulsed wave stimulation induces shear stress and thus increases algal lipid production.

Efficacy of low-intensity pulsed ultrasound in the prevention of osteoporosis following spinal cord injury

Ultrasound (US), a high-frequency acoustic energy traveling in the form of a mechanical wave, represents a potential site-specific intervention for osteoporosis. Bone is a dynamic tissue that remodels in response to applied mechanical stimuli. As a form of mechanical stimulation, US is anticipated to produce a similar remodeling response. This theory is supported by growing in vitro and in vivo evidence demonstrating an osteogenic effect of pulsed-wave US at low spatial-averaged temporal-averaged intensities. The aim of this study was to investigate whether low-intensity pulsed US could prevent calcaneal osteoporosis in individuals following spinal cord injury (SCI). Fifteen patients with a 1–6 month history of SCI were recruited. Active US was introduced to one heel for 20 min/day, 5 days/week, over 6 weeks. The contralateral heel was simultaneously treated with inactive US. Patients were blind to which heel was being actively treated. Active US pulsed with a 10 μsec burst of 1.0 MHz sine waves repeating at 3.3 kHz. The spatial-averaged temporal-averaged intensity was set at 30 mW/cm 2. Bone status was assessed at baseline and following the intervention period by dual-energy X-ray absorptiometry and quantitative US. SCI resulted in significant bone loss. Bone mineral content decreased by 7.5 ± 3.0% in inactive US-treated calcanei ( p < 0.001). Broadband US attenuation and speed of sound decreased by 8.5 ± 6.9% ( p < 0.001) and 1.5 ± 1.3% ( p < 0.001), respectively. There were no differences between active and inactive US-treated calcanei for any skeletal measure ( p > 0.05). These findings confirm the negative skeletal impact of SCI, and demonstrate that US at the dose and mode administered was not a beneficial intervention for SCI-induced osteoporosis. This latter finding may primarily relate to the inability of US to effectively penetrate the outer cortex of bone due to its acoustic properties.

Development of tissue culture techniques and hardware to study mineralization under microgravity conditions

To study the effects of weightlessness on mouse fetal long bone rudiment growth and mineralization we have developed a tissue culture system for the Biorack facility of Spacelab. The technique uses standard liquid tissue culture medium, supplemented with Na-β-glycerophosphate, confined in gas permeable polyethylene bags mounted inside ESA Biorack Type I experiment containers. The containers can be flushed with an air/5% CO 2 gas mixture necessary for the physiological bicarbonate buffer used. Small amounts of fluid can be introduced at the beginning (e.g. radioactive labels for incorporation studies) or at the end of the experiment (fixatives). A certain form of mechanical stimulation (continuous compression) can be used to counteract the, possibly, adverse effect of μ-gravity. Using 16 day old metatarsals the in vitro calcification process under μ-gravity conditions can be studied for a 4 day period.

Effects of Mechanical Stimulation on Avena Coleoptile Segment Elongation in a High Resolution, Continuous Growth-recording System

The effects of an abrasive mechanical stimulation of the inner epidermal surfaces of excised Avena coleoptile segments were examined in relation to growth in the presence and absence of exogenously supplied indole-3-acetic acid. Mechanical stimulation of this nature, provided immediately following excision, was found to elicit a small, transient increase in endogenous growth rate which contributed to a larger initial rapid growth response (previously referred to as a tactile response). These results, contrary to the earlier reports, suggest that the inner epidermal mechanical or tactile stimulation does not account for the entire initial rapid growth response. Preliminary experiments indicate that an alternative form of mechanical stimulation (segment excision) may contribute to that portion of initial rapid growth which is not attributable to inner epidermal abrasion.Following its initial growth-enhancing effect, inner epidermal stimulation had either no effect or in some cases appeared inhibitory to endogenous growth. Growth in response to exogenous auxin was appreciably inhibited by this form of mechanical stimulation.

Sensory hind-limb representation in Sml cortex of the cat. A unit analysis

A unit analysis was made of mechanoreception in the hind limb area of the cat primary somatosensory cortex, SmI. A sample of 588 units was studied in this area. Eighty per cent of the units were influenced by light mechanical peripheral stimulation of the contralateral hind limb; the remainder were not influenced by any form of mechanical stimulation. No ipsilateral representation was found. Most excitable units were situated in the middle cortical layers. All were characterized by static lemniscal properties, i.e., short latency, and also place as well as modality specificity. These units were distributed with a somatotopic organization. Excitable units which could be defined in terms of adaptive property and adequate stimulus were classified as hair, touch, tap, pressure or joint. The representation of slowly-adapting joint receptors was slight, and there was no evidence for the representation of muscle stretch receptors or Golgi tendon organs. The submodalities which were represented were topographically distributed in caudomedial to rostrolateral gradients of epidermal and subepidermal receptors. This distribution appears to be correlated with the cortical architecture.