Limits...
Mechanobiological modulation of cytoskeleton and calcium influx in osteoblastic cells by short-term focused acoustic radiation force.

Zhang S, Cheng J, Qin YX - PLoS ONE (2012)

Bottom Line: Cell viability was not affected.Application of pulsed ultrasound radiation generated only a minimal temperature rise of 0.1°C, and induced a streaming resulting fluid shear stress of 0.186 dyne/cm(2), suggesting that hyperthermia and acoustic streaming might not be the main causes of the observed cell responses.In conclusion, these data provide more insight in the interactions between acoustic mechanical stress and osteoblastic cells.

View Article: PubMed Central - PubMed

Affiliation: Department of Biomedical Engineering, Stony Brook University, Stony Brook, New York, United States of America.

ABSTRACT
Mechanotransduction has demonstrated potential for regulating tissue adaptation in vivo and cellular activities in vitro. It is well documented that ultrasound can produce a wide variety of biological effects in biological systems. For example, pulsed ultrasound can be used to noninvasively accelerate the rate of bone fracture healing. Although a wide range of studies has been performed, mechanism for this therapeutic effect on bone healing is currently unknown. To elucidate the mechanism of cellular response to mechanical stimuli induced by pulsed ultrasound radiation, we developed a method to apply focused acoustic radiation force (ARF) (duration, one minute) on osteoblastic MC3T3-E1 cells and observed cellular responses to ARF using a spinning disk confocal microscope. This study demonstrates that the focused ARF induced F-actin cytoskeletal rearrangement in MC3T3-E1 cells. In addition, these cells showed an increase in intracellular calcium concentration following the application of focused ARF. Furthermore, passive bending movement was noted in primary cilium that were treated with focused ARF. Cell viability was not affected. Application of pulsed ultrasound radiation generated only a minimal temperature rise of 0.1°C, and induced a streaming resulting fluid shear stress of 0.186 dyne/cm(2), suggesting that hyperthermia and acoustic streaming might not be the main causes of the observed cell responses. In conclusion, these data provide more insight in the interactions between acoustic mechanical stress and osteoblastic cells. This experimental system could serve as basis for further exploration of the mechanosensing mechanism of osteoblasts triggered by ultrasound.

Show MeSH

Related in: MedlinePlus

Measured average ultrasound-induced temperature rise vs. duration of different acoustical power and stimulation modes.Error bars (30-s intervals) show the standard deviation between the different measurements. Temperature was measured with a thermocouple probe immersed in the culture medium.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC3368843&req=5

pone-0038343-g003: Measured average ultrasound-induced temperature rise vs. duration of different acoustical power and stimulation modes.Error bars (30-s intervals) show the standard deviation between the different measurements. Temperature was measured with a thermocouple probe immersed in the culture medium.

Mentions: Ultrasound pressure distribution showed a clear peak at the center of the focal region (Figure 2B). Therefore, the temperature changes were specifically measured in this area of the culture dish. In the continuous radiation mode for 3 min, the results showed that the temperature of the central region of the culture dish initially rose quickly at the start of ultrasound radiation and then the increase slowed down after two minutes of radiation (Figure 3). The maximum rise of temperature during the radiation was approximately 1.3°C. The temperature rise was much less during pulsed radiation compared to that of continuous radiation mode, with an increase of less than 0.3°C at ultrasound power of 6 W at the end of three-minute-radiation. In addition, lower ultrasound power of 3 W caused lower temperature rise of 0.1°C. The temperature rise during ultrasound radiation may affect general metabolism and morphological structure of MC3T3-E1 osteoblasts. Hence, the pulsed ultrasound radiation mode and power to 6 W were selected for the following biological study in which the temperature rise was no more than 0.1°C over one minute radiation.


Mechanobiological modulation of cytoskeleton and calcium influx in osteoblastic cells by short-term focused acoustic radiation force.

Zhang S, Cheng J, Qin YX - PLoS ONE (2012)

Measured average ultrasound-induced temperature rise vs. duration of different acoustical power and stimulation modes.Error bars (30-s intervals) show the standard deviation between the different measurements. Temperature was measured with a thermocouple probe immersed in the culture medium.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3368843&req=5

pone-0038343-g003: Measured average ultrasound-induced temperature rise vs. duration of different acoustical power and stimulation modes.Error bars (30-s intervals) show the standard deviation between the different measurements. Temperature was measured with a thermocouple probe immersed in the culture medium.
Mentions: Ultrasound pressure distribution showed a clear peak at the center of the focal region (Figure 2B). Therefore, the temperature changes were specifically measured in this area of the culture dish. In the continuous radiation mode for 3 min, the results showed that the temperature of the central region of the culture dish initially rose quickly at the start of ultrasound radiation and then the increase slowed down after two minutes of radiation (Figure 3). The maximum rise of temperature during the radiation was approximately 1.3°C. The temperature rise was much less during pulsed radiation compared to that of continuous radiation mode, with an increase of less than 0.3°C at ultrasound power of 6 W at the end of three-minute-radiation. In addition, lower ultrasound power of 3 W caused lower temperature rise of 0.1°C. The temperature rise during ultrasound radiation may affect general metabolism and morphological structure of MC3T3-E1 osteoblasts. Hence, the pulsed ultrasound radiation mode and power to 6 W were selected for the following biological study in which the temperature rise was no more than 0.1°C over one minute radiation.

Bottom Line: Cell viability was not affected.Application of pulsed ultrasound radiation generated only a minimal temperature rise of 0.1°C, and induced a streaming resulting fluid shear stress of 0.186 dyne/cm(2), suggesting that hyperthermia and acoustic streaming might not be the main causes of the observed cell responses.In conclusion, these data provide more insight in the interactions between acoustic mechanical stress and osteoblastic cells.

View Article: PubMed Central - PubMed

Affiliation: Department of Biomedical Engineering, Stony Brook University, Stony Brook, New York, United States of America.

ABSTRACT
Mechanotransduction has demonstrated potential for regulating tissue adaptation in vivo and cellular activities in vitro. It is well documented that ultrasound can produce a wide variety of biological effects in biological systems. For example, pulsed ultrasound can be used to noninvasively accelerate the rate of bone fracture healing. Although a wide range of studies has been performed, mechanism for this therapeutic effect on bone healing is currently unknown. To elucidate the mechanism of cellular response to mechanical stimuli induced by pulsed ultrasound radiation, we developed a method to apply focused acoustic radiation force (ARF) (duration, one minute) on osteoblastic MC3T3-E1 cells and observed cellular responses to ARF using a spinning disk confocal microscope. This study demonstrates that the focused ARF induced F-actin cytoskeletal rearrangement in MC3T3-E1 cells. In addition, these cells showed an increase in intracellular calcium concentration following the application of focused ARF. Furthermore, passive bending movement was noted in primary cilium that were treated with focused ARF. Cell viability was not affected. Application of pulsed ultrasound radiation generated only a minimal temperature rise of 0.1°C, and induced a streaming resulting fluid shear stress of 0.186 dyne/cm(2), suggesting that hyperthermia and acoustic streaming might not be the main causes of the observed cell responses. In conclusion, these data provide more insight in the interactions between acoustic mechanical stress and osteoblastic cells. This experimental system could serve as basis for further exploration of the mechanosensing mechanism of osteoblasts triggered by ultrasound.

Show MeSH
Related in: MedlinePlus