a Key Laboratory of Medicinal Resources and Natural Pharmaceutical Chemistry, Ministry of Education, National Engineering Laboratory for Resource Developing of Endangered Chinese Crude Drugs in Northwest of China, College of Life Sciences, Shaanxi Normal University, Xi'an, Shaanxi, China
b Laboratory of Biophysics and Biomedicine, College of Physics and Information Technology, Shaanxi Normal University, Xi'an, Shaanxi, China
a b s t r a c t
Objectives: The aim of this study was to compare the cell membrane damage induced by ultrasound at different intensities between MCF-7/ADR cells and MCF-7 cells.
Methods: Tumor cells in the culture dishes (35 mm diameter) were exposed to planner ultrasound at intensities range from 0.25 W/cm2 to 0.75 W/cm2 for 60 s. The viability of cells was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay and Guava Viacount assay. The cell membrane integrity was estimated by flow cytometry using propidium iodide (PI) staining and cellular uptake of fluorescein isothiocyanate-dextran (FD500). The membrane lipid peroxidation and membrane fluidity were also specially compared between two cell lines in this paper using spectrophotometry. Ultrastructural alterations on membrane surface were observed by scanning electron microscopy.
Results: The ultrasound produced cytotoxicity in both cell lines increased with the irradiation intensity increased from 0.25 W/cm2 to 0.75 W/cm2. Cell membrane permeability and the level of lipid peroxidation were remarkably enhanced after ultrasound application. In addition, relatively severe cell damage was observed under scanning electron microscopy after 0.75 W/cm2 ultrasound treatment.
Conclusions: Ultrasound exposure decreased MCF-7 and MCF-7/ADR cell viability in an intensity-dependent manner and MCF-7/ADR cells were more sensitive to ultrasound exposure than MCF-7 cells at the same experimental conditions. The declined membrane fluidity in MCF-7/ADR cell may be one of the reasons for its increased membrane damage.