In vitro effects of therapeutic ultrasound on the nucleus of human fibroblasts

Department of Physical Therapy, University of Maryland at Baltimore 21201, USA.

BACKGROUND AND PURPOSE. The purpose of this investigation was to examine the cytological effects of therapeutic ultrasound on human fibroblasts. MATERIAL AND METHODS. Using an in vitro approach, the number of cells recovered, the morphology of chromosomes, and the presence of mitotic spindles were studied after sonication of human fibroblasts in culture. The ultrasound output had a frequency of 1 MHz and was delivered in a pulse mode of 2 milliseconds "on" and 8 milliseconds "off." Sonication was given for 0, 30, 60, and 90 seconds. RESULTS. There was a time-dependent decrease in number of cells recovered, a fourfold increase in mitotic index in the cells that survived the treatment, and a nearly eightfold increase of chromosomal aberrations with loss of mitotic spindles. CONCLUSION AND DISCUSSION. The dose-dependent lytic effect of nonthermal ultrasound could result in fractionation of cells, which might facilitate phagocytosis during chronic inflammation. In addition, we observed an increase in chromosomal aberrations and a loss of mitotic spindles as a result of an extremely short ultrasound treatment (30 seconds). Whether these alterations are mutagenic or not warrants further study. It is possible that in our in vitro experiments, the ultrasound received was greater than would occur in a clinical situation.

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				K. G Baker, V. J Robertson, and F. A Duck A Review of Therapeutic Ultrasound: Biophysical Effects Physical Therapy, July 1, 2001; 81(7): 1351 - 1358. [Abstract] [Full Text] [PDF]