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Conference Paper: Real-time imaging of cellular dynamics during low-intensity pulsed ultrasound exposure

TitleReal-time imaging of cellular dynamics during low-intensity pulsed ultrasound exposure
Authors
Issue Date2013
PublisherISTU2013.
Citation
The 13th International Symposium on Therapeutic Ultrasound (ISTU 2013), Shanghai, China, 12-16 May 2013. In 13th ISTU Final Programme, 2013, p. 89 How to Cite?
AbstractOBJECTIVE: Although the therapeutic potential of low-intensity pulsed ultrasound is unquestionable, the wave-matter interactions involved in the process remain to be vaguely characterized. Here we seek to undertake a series of in-situ cellular imaging studies that aim to analyze the mechanical impact of low-intensity pulsed ultrasound on attached fibroblasts from three different aspects: membrane, cytoskeleton, and nucleus. METHODS: Our experimental platform comprised an in-house ultrasound exposure hardware that was coupled to a confocal microscopy system. The waveguided ultrasound beam was geometrically aligned to the microscope’s fieldof-view that corresponds to the center of a polystyrene dish containing fibroblasts. Short ultrasound pulses (5 cycles; 2 kHz PRF) with 0.8 MPa peak acoustic pressure (0.21 W/cm2 SPTA intensity) were delivered over a 10 min period. Live imaging was performed on both membrane (CellMask) and cytoskeleton (actin-GFP, tubulin-RFP) over the entire observation period (up to 30 min after end of exposure). Also, pre- and post-exposure fixed-cell imaging was conducted on the nucleus (Hoechst 33342) and two cytoskeleton components related to stress fibers: F-actin (phalloidin-FITC) and vincullin (Alexa Fluor 647 conjugated). To study whether mechanotransduction was responsible in mediating ultrasound-cell interactions, some experiments were conducted with the addition of gadolinium that blocks stretch-sensitive ion channels. RESULTS: Cell shrinkage was evident over the course of low-intensity pulsed ultrasound exposure. This was accompanied with contraction of actin and tubulin. Also, an increase in central stress fibers was observed at the end of exposure, while the nucleus was found to have decreased in size. Interestingly, after the exposure, a significant rebound in cell volume was observed over a 30 min. period. These effects were not observed in cases with gadolinium blockage of mechanosensitive ion channels. CONCLUSIONS: Our results suggest that low-intensity pulsed ultrasound would transiently induce remodeling of a cell’s membrane and cytoskeleton, and it will lead to repression of nucleus. This indicates that ultrasound after all represents a mechanical stress on cellular membrane. The post-exposure outgrowth phenomenon is also of practical relevance as it may be linked to the stimulatory effects that have been already observed in low-intensity pulsed ultrasound treatments.
DescriptionOral Session 5 - Bioeffects of therapeutic ultrasound
Control ID: 1671584
Persistent Identifierhttp://hdl.handle.net/10722/189835

 

DC FieldValueLanguage
dc.contributor.authorHu, Yen_US
dc.contributor.authorYu, ACHen_US
dc.contributor.authorWan, JMFen_US
dc.date.accessioned2013-09-17T15:00:47Z-
dc.date.available2013-09-17T15:00:47Z-
dc.date.issued2013en_US
dc.identifier.citationThe 13th International Symposium on Therapeutic Ultrasound (ISTU 2013), Shanghai, China, 12-16 May 2013. In 13th ISTU Final Programme, 2013, p. 89en_US
dc.identifier.urihttp://hdl.handle.net/10722/189835-
dc.descriptionOral Session 5 - Bioeffects of therapeutic ultrasound-
dc.descriptionControl ID: 1671584-
dc.description.abstractOBJECTIVE: Although the therapeutic potential of low-intensity pulsed ultrasound is unquestionable, the wave-matter interactions involved in the process remain to be vaguely characterized. Here we seek to undertake a series of in-situ cellular imaging studies that aim to analyze the mechanical impact of low-intensity pulsed ultrasound on attached fibroblasts from three different aspects: membrane, cytoskeleton, and nucleus. METHODS: Our experimental platform comprised an in-house ultrasound exposure hardware that was coupled to a confocal microscopy system. The waveguided ultrasound beam was geometrically aligned to the microscope’s fieldof-view that corresponds to the center of a polystyrene dish containing fibroblasts. Short ultrasound pulses (5 cycles; 2 kHz PRF) with 0.8 MPa peak acoustic pressure (0.21 W/cm2 SPTA intensity) were delivered over a 10 min period. Live imaging was performed on both membrane (CellMask) and cytoskeleton (actin-GFP, tubulin-RFP) over the entire observation period (up to 30 min after end of exposure). Also, pre- and post-exposure fixed-cell imaging was conducted on the nucleus (Hoechst 33342) and two cytoskeleton components related to stress fibers: F-actin (phalloidin-FITC) and vincullin (Alexa Fluor 647 conjugated). To study whether mechanotransduction was responsible in mediating ultrasound-cell interactions, some experiments were conducted with the addition of gadolinium that blocks stretch-sensitive ion channels. RESULTS: Cell shrinkage was evident over the course of low-intensity pulsed ultrasound exposure. This was accompanied with contraction of actin and tubulin. Also, an increase in central stress fibers was observed at the end of exposure, while the nucleus was found to have decreased in size. Interestingly, after the exposure, a significant rebound in cell volume was observed over a 30 min. period. These effects were not observed in cases with gadolinium blockage of mechanosensitive ion channels. CONCLUSIONS: Our results suggest that low-intensity pulsed ultrasound would transiently induce remodeling of a cell’s membrane and cytoskeleton, and it will lead to repression of nucleus. This indicates that ultrasound after all represents a mechanical stress on cellular membrane. The post-exposure outgrowth phenomenon is also of practical relevance as it may be linked to the stimulatory effects that have been already observed in low-intensity pulsed ultrasound treatments.-
dc.languageengen_US
dc.publisherISTU2013.-
dc.relation.ispartof13th International Symposium on Therapeutic Ultrasound Final Programmeen_US
dc.rightsCreative Commons: Attribution 3.0 Hong Kong License-
dc.titleReal-time imaging of cellular dynamics during low-intensity pulsed ultrasound exposureen_US
dc.typeConference_Paperen_US
dc.identifier.emailYu, ACH: alfred.yu@hku.hken_US
dc.identifier.emailWan, JMF: jmfwan@hku.hken_US
dc.identifier.authorityYu, ACH=rp00657en_US
dc.identifier.authorityWan, JMF=rp00798en_US
dc.description.naturepostprint-
dc.identifier.hkuros222140en_US
dc.identifier.spage89-
dc.identifier.epage89-
dc.publisher.placeChina-

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