Assessment of fibroblast cells submitted to ultrasonic irradiation

Abstract

Physiotherapists consider ultrasound an indispensable tool, which is commonly employed in clinical practice as a treatment aid for musculoskeletal dysfunctions. The aim of our study has been to analyze fibroblast cell structures following low-intensity pulsed ultrasonic irradiation. Fibroblast cell cultures irradiated with ultrasound were analyzed through electron microscopy to determine an ideal irradiation beam that preserved cell morphology and integrity. Analysis by fluorescence microscopy and transmission electron microscopy was used to follow morphological changes of the nucleus and cytoskeleton following different ultrasound irradiation intensities. According to the parameters used in the pulsed irradiation of fibroblast cultures, control over the intensity employed is fundamental to the optimal use of therapeutic ultrasound. Cell cultures submitted to low-intensity pulsed ultrasonic irradiation (0.2-0.6 W/cm2) at 10% (1:9 duty cycle) and 20% (2:8 duty cycle) maintained shape and cellular integrity, with little damage. In the group irradiated with an intensity of 0.8 W/cm2, a loss of adhesion was observed along with an alteration in the morphology of some cells at an intensity of 1.0 W/cm2, which resulted in the presence of cellular fragments and a decrease of adhering cells. In cells irradiated at 2.0 W/cm2, there was a complete loss of adhesion and aggregation of cellular fragments. The present study confirms that biophysical properties of pulsed ultrasound may accelerate proliferation processes in different biological tissues.

Pulsed-low intensity ultrasound enhances extracellular matrix production by fibroblasts encapsulated in alginate

“…6 considered this increase in cell number to be a deleterious effect because the cells are involved in cellular division instead of collagen production. Their belief is supported by a previous study showing that fibroblasts submitted to PLIUS (intensity = 0.2–0.6 W/cm 2 ) at a 10% and 20% duty cycle can maintain their shape and integrity and also increase in number 34 ; the intensity and duty cycle for PLIUS used in the present study are within this range. However, it is not clear why the cell number increased after 10 days of PLIUS treatment.…”

Short-Term Effect of Low-Intensity Pulsed Ultrasound on an Ex-Vivo 3-D Tooth Culture

“…Secondly, the characteristics and technique of ultrasound application are different. Furthermore, studies that documented adverse effects histologically used higher intensities (0.2-1 W/cm 2 ), but in our study, the LIPUS power emitted from the transducer did not exceed 33 mW/cm 2 (de Oliveira et al 2008).…”

Effect of therapeutic ultrasound of low intensity pulsed and continuous in fibroblastic cells in vitro

“…Likewise, according to Oliveira et al, (9) irradiation at doses of 0,2 and 0,6 W/cm 2 in both the 10% and 20% pulse rates over the 72 hour period increased the viability of L929 fibroblast cells, being significantly higher than in the non-irradiated group.…”

“…(4,5) On the other hand, the second, athermic, obtained in the output with pulses, is usually directed to the treatment of more severe or acute injuries, to improve the quality and speed of the recovery without increasing the local temperature. (6) In this sense, several authors report the efficiency of low intensity ultrasound in the percentage increase of viable cells cultured in vitro, with acceleration of proliferation and, (7)(8)(9) with the continuous, relevant therapeutic effects both in vivo and in vitro. (1,10) Furthermore, in the continuous mode, effects on the expression of cartilage specific mRNA in chondrocyte culture, (11) hypertrophy of muscle fibers, (1) or with pulsed modulation in biosynthetic activity and expression of integrins (12) and stimulation of anti-inflammatory systems in synovial membrane cells.…”

“…(13) It is worth mentioning that although the effects of ultrasound have already been well described, the ideal dose-effect relationship still needs to be better elucidated and delimited. (7)(8)(9)14) MTP&RehabJournal 2017, 15: 459 In this way, this study aimed to evaluate the influence of pulsed and continuous ultrasound irradiation on the viability of L929 fibroblast cells in vitro.…”