Dielectric Changes in Membrane Properties and Cell Interiors of Human Mesothelial Cells in Vitro after Crocidolite Asbestos Exposure

Abstract

Asbestos induces cytogenetic and genotoxic effects in cultured cell lines in vitro. For fiuther investigations of the fiber-induced cellular changes, electrorotation (ROT) measurements can be used to determine early changes of surface properties and dielectric cellular changes. In the present study, human mesothelial cells (HMC) were exosed to nontoxic concentrations of crocidolite asbestos (1 pg/cm2) for 12, 24, 30, 50, and 72 hr, and were investigated for changes in dielectric properties, morphologic and biochemical changs using ROT measurements, electron microscopy, and flow cytometry, respectively. The results of ROT measurements raled slighdy increased internal conductivity and decreased membrane conductance ofHMC during the first 12 hr of exposure to crocidolite. This may be due to functional changes of ion channels of the cellular membrane. However, after exposures of. 30 hr, reduced internal conductivity and increasd membrane conductance of HMC occurred. These effects may be caused by permeabilization ofthe cell membrane and the leakage of ions into the surrounding medium. The membrane capacitance of HMC is always decreased during exposure of cells to crocidolite fibers. This decreased membrane capacitance may result from the observed reduction in the number of microvilli and from the shrnkage of cells as observed by electron microscopy and flow cytometry. Changes in composition of the plasma membrane were also observed after the labeling of phosphatidylserines (PS) on the cell surface. These observed changes can be related to apoptotic events. Whereas during the first 50 hr of exposure only a small number of HMC with increased exposure of PS on the cell surface was detected by flow cytometry, the dielectric properties of HMC showed marked changes during this time. Our results show that surface property changes of the cellular membrane of HMC as well as interior dielectric change occur after the exposure ofcells to crocidolite fibers. The observed changes are discussed in terms of complex combined cellular effects after amphibole asbestos exposure. Key words apoptosis, crocidolite, electron microscopy, electrorotation, flow cytometry, phosphatidylserine, plasma membrane.

Synchrotron X-ray microscopy reveals early calcium and iron interaction with crocidolite fibers in the lung of exposed mice

“…It is believed that membrane damage allow the influx of extracellular Ca ions into the cell, where it complexes with phosphate groups, ultimately forming crystalline apatite (Trump et al, 1980). In the case of asbestos-induced calcification, it is not entirely clear how the fibers initially interact with cell membranes (Harington et al, 1975;Hill, 1982, 1983;Hesterberg et al, 1986;Malorni et al, 1990;Elferink and Kelters, 1991;Dopp et al, 2000;Nagai and Toyokuni, 2012;Bernareggi et al, 2015), nor is it known why the precipitates form intracellular deposits around asbestos fibers as earlier described by Brody and Hill (Brody and Hill, 1982).…”

Multifrequency permittivity measurements enable on‐line monitoring of changes in intracellular conductivity due to nutrient limitations during batch cultivations of CHO cells

“…7,50,51 r i is nevertheless known to increase during early apoptosis, possibly due to cell shrinkage, and decreases after induced morphological changes or in late-apoptotic and necrotic cells. [52][53][54] Ion efflux leads to a decrease of r i , which can also be observed after an increase in membrane conductance, for example, because of antibiotic treatment. 55,56 Differences in r i are most likely attributable to different ion concentrations in the cell's interior.…”

Dielectrophoretic analysis of the impact of isopropyl alcohol on the electric polarisability of Escherichia coli whole-cells

“…the dielectric permittivity and conductivity [36]. Therefore, dielectrophoresis is a sensitive method that is capable to study changes in the cell membrane and detects differences in the cell's electrophysiology [15,[17][18][19][20][21][22].…”

“…They monitored the changes during the cell cycle and could distinguish the different cell status [9]. Several groups exploited the dielectrophoretic response of various cells for characterisation and separation purposes [17][18][19][20][21][22][23]. Jones et al reported that E. coli of different serotypes could be discriminated by their dielectric response [19].…”